Create WD candidate for NSD API (proposed publication: 2014-02-20)
authorRich Tibbett <richt@opera.com>
Tue, 18 Feb 2014 14:39:27 +0100
changeset 494 8a46b5017a1a
parent 493 680c8211ecc1
child 495 d5fcbdf39f63
Create WD candidate for NSD API (proposed publication: 2014-02-20)
discovery-api/WD_20140220.html
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/discovery-api/WD_20140220.html	Tue Feb 18 14:39:27 2014 +0100
@@ -0,0 +1,3421 @@
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+    </title>
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+      <p>
+        <a href="http://www.w3.org/"><img width="72"
+             height="48"
+             src="https://www.w3.org/Icons/w3c_home"
+             alt="W3C"></a>
+      </p>
+      <h1 class="title p-name"
+          id="title"
+          property="dcterms:title">
+        Network Service Discovery
+      </h1>
+      <h2 property="dcterms:issued"
+          datatype="xsd:dateTime"
+          content="2014-02-19T23:00:00.000Z"
+          id="w3c-working-draft-20-february-2014">
+        <abbr title="World Wide Web Consortium">W3C</abbr> Working Draft <time class="dt-published"
+            datetime="2014-02-20">20 February 2014</time>
+      </h2>
+      <dl>
+        <dt>
+          This version:
+        </dt>
+        <dd>
+          <a class="u-url"
+              href=
+              "http://www.w3.org/TR/2014/WD-discovery-api-20140220/">http://www.w3.org/TR/2014/WD-discovery-api-20140220/</a>
+        </dd>
+        <dt>
+          Latest published version:
+        </dt>
+        <dd>
+          <a href="http://www.w3.org/TR/discovery-api/">http://www.w3.org/TR/discovery-api/</a>
+        </dd>
+        <dt>
+          Latest editor's draft:
+        </dt>
+        <dd>
+          <a href=
+          "http://dvcs.w3.org/hg/dap/raw-file/tip/discovery-api/Overview.html">http://dvcs.w3.org/hg/dap/raw-file/tip/discovery-api/Overview.html</a>
+        </dd>
+        <dt>
+          Previous version:
+        </dt>
+        <dd>
+          <a rel="dcterms:replaces"
+              href=
+              "http://www.w3.org/TR/2013/WD-discovery-api-20130924/">http://www.w3.org/TR/2013/WD-discovery-api-20130924/</a>
+        </dd>
+        <dt>
+          Editor:
+        </dt>
+        <dd class="p-author h-card vcard"
+            rel="bibo:editor"
+            inlist="">
+          <span typeof="foaf:Person"><span property="foaf:name"
+                class="p-name fn">Rich Tibbett</span>, <a rel="foaf:workplaceHomepage"
+             class="p-org org h-org h-card"
+             href="http://opera.com/">Opera Software ASA</a></span>
+        </dd>
+      </dl>
+      <p class="copyright">
+        <a href="http://www.w3.org/Consortium/Legal/ipr-notice#Copyright">Copyright</a> © 2014 <a href=
+        "http://www.w3.org/"><abbr title="World Wide Web Consortium">W3C</abbr></a><sup>®</sup> (<a href=
+        "http://www.csail.mit.edu/"><abbr title="Massachusetts Institute of Technology">MIT</abbr></a>, <a href=
+        "http://www.ercim.eu/"><abbr title=
+        "European Research Consortium for Informatics and Mathematics">ERCIM</abbr></a>, <a href=
+        "http://www.keio.ac.jp/">Keio</a>, <a href="http://ev.buaa.edu.cn/">Beihang</a>), All Rights Reserved.
+        <abbr title="World Wide Web Consortium">W3C</abbr> <a href=
+        "http://www.w3.org/Consortium/Legal/ipr-notice#Legal_Disclaimer">liability</a>, <a href=
+        "http://www.w3.org/Consortium/Legal/ipr-notice#W3C_Trademarks">trademark</a> and <a href=
+        "http://www.w3.org/Consortium/Legal/copyright-documents">document use</a> rules apply.
+      </p>
+      <hr>
+    </div>
+    <section id="abstract"
+             class="introductory"
+             property="dcterms:abstract"
+             datatype=""
+             typeof="bibo:Chapter"
+             resource="#ref"
+             rel="bibo:Chapter">
+      <h2 aria-level="1"
+          role="heading"
+          id="h2_abstract">
+        Abstract
+      </h2>
+      <p>
+        This specification defines a mechanism for an HTML document to discover and subsequently communicate with
+        <abbr title="Hypertext Transfer Protocol">HTTP</abbr>-based services advertised via common discovery protocols
+        within the current network.
+      </p>
+    </section>
+    <section id="sotd"
+             class="introductory"
+             typeof="bibo:Chapter"
+             resource="#ref"
+             rel="bibo:Chapter">
+      <h2 aria-level="1"
+          role="heading"
+          id="h2_sotd">
+        Status of This Document
+      </h2>
+      <p>
+        <em>This section describes the status of this document at the time of its publication. Other documents may
+        supersede this document. A list of current <abbr title="World Wide Web Consortium">W3C</abbr> publications and
+        the latest revision of this technical report can be found in the <a href="http://www.w3.org/TR/"><abbr title=
+        "World Wide Web Consortium">W3C</abbr> technical reports index</a> at http://www.w3.org/TR/.</em>
+      </p>
+      <p>
+        This version of the specification is an update to the previously published <a href="http://www.w3.org/TR/2013/WD-discovery-api-20130924/">24 September 2013 Working Draft</a> version of the same document.
+      </p>
+
+      <p>
+        A full <a href="#change-log">change log</a> is available for this specification and a
+        <a href="http://services.w3.org/htmldiff?doc1=http%3A%2F%2Fwww.w3.org%2FTR%2F2013%2FWD-discovery-api-20130924%2F&amp;doc2=https%3A%2F%2Fdvcs.w3.org%2Fhg%2Fdap%2Fraw-file%2Ftip%2Fdiscovery-api%2FWD-20140220.html">
+          full HTML diff</a> is also available. Significant changes from the previously published working draft include updates
+          to the privacy and security considerations of this API, adding CORS support and the preliminary CORS check procedure,
+          improvements to garbage collection and other minor technical clarifications.
+      </p>
+      <p>
+        This document was published by the <a href="http://www.w3.org/2009/dap/">Device APIs Working Group</a> as a
+        Working Draft. This document is intended to become a <abbr title="World Wide Web Consortium">W3C</abbr>
+        Recommendation. If you wish to make comments regarding this document, please send them to <a href=
+        "mailto:[email protected]">[email protected]</a> (<a href=
+        "mailto:[email protected]?subject=subscribe">subscribe</a>, <a href=
+        "http://lists.w3.org/Archives/Public/public-device-apis/">archives</a>). All comments are welcome.
+      </p>
+      <p>
+        Publication as a Working Draft does not imply endorsement by the <abbr title=
+        "World Wide Web Consortium">W3C</abbr> Membership. This is a draft document and may be updated, replaced or
+        obsoleted by other documents at any time. It is inappropriate to cite this document as other than work in
+        progress.
+      </p>
+      <p>
+        This document was produced by a group operating under the <a id="sotd_patent"
+           about=""
+           rel="w3p:patentRules"
+           href="http://www.w3.org/Consortium/Patent-Policy-20040205/">5 February 2004 <abbr title=
+           "World Wide Web Consortium">W3C</abbr> Patent Policy</a>. <abbr title="World Wide Web Consortium">W3C</abbr>
+           maintains a <a href="http://www.w3.org/2004/01/pp-impl/43696/status"
+           rel="disclosure">public list of any patent disclosures</a> made in connection with the deliverables of the
+           group; that page also includes instructions for disclosing a patent. An individual who has actual knowledge
+           of a patent which the individual believes contains <a href=
+           "http://www.w3.org/Consortium/Patent-Policy-20040205/#def-essential">Essential Claim(s)</a> must disclose
+           the information in accordance with <a href=
+           "http://www.w3.org/Consortium/Patent-Policy-20040205/#sec-Disclosure">section 6 of the <abbr title=
+           "World Wide Web Consortium">W3C</abbr> Patent Policy</a>.
+      </p>
+    </section>
+    <section id="toc">
+      <h2 class="introductory"
+          aria-level="1"
+          role="heading"
+          id="h2_toc">
+        Table of Contents
+      </h2>
+      <ul class="toc"
+          role="directory"
+          id="respecContents">
+        <li class="tocline">
+          <a href="#introduction"
+              class="tocxref"><span class="secno">1.</span> Introduction</a>
+        </li>
+        <li class="tocline">
+          <a href="#conformance"
+              class="tocxref"><span class="secno">2.</span> Conformance</a>
+          <ul class="toc">
+            <li class="tocline">
+              <a href="#dependencies"
+                  class="tocxref"><span class="secno">2.1</span> Dependencies</a>
+            </li>
+          </ul>
+        </li>
+        <li class="tocline">
+          <a href="#terminology"
+              class="tocxref"><span class="secno">3.</span> Terminology</a>
+        </li>
+        <li class="tocline">
+          <a href="#security-and-privacy-considerations"
+              class="tocxref"><span class="secno">4.</span> Security and privacy considerations</a>
+          <ul class="toc">
+            <li class="tocline">
+              <a href="#security-considerations-for-api-implementations"
+                  class="tocxref"><span class="secno">4.1</span> Security considerations for <abbr title=
+                  "Application Programming Interface">API</abbr> implementations</a>
+            </li>
+            <li class="tocline">
+              <a href="#privacy-considerations-for-api-implementations"
+                  class="tocxref"><span class="secno">4.2</span> Privacy considerations for <abbr title=
+                  "Application Programming Interface">API</abbr> implementations</a>
+            </li>
+            <li class="tocline">
+              <a href="#additional-api-implementation-considerations"
+                  class="tocxref"><span class="secno">4.3</span> Additional <abbr title=
+                  "Application Programming Interface">API</abbr> implementation considerations</a>
+            </li>
+          </ul>
+        </li>
+        <li class="tocline">
+          <a href="#requesting-networked-services"
+              class="tocxref"><span class="secno">5.</span> Requesting networked services</a>
+          <ul class="toc">
+            <li class="tocline">
+              <a href="#methods"
+                  class="tocxref"><span class="secno">5.1</span> Methods</a>
+            </li>
+            <li class="tocline">
+              <a href="#error-handling"
+                  class="tocxref"><span class="secno">5.2</span> Error Handling</a>
+            </li>
+          </ul>
+        </li>
+        <li class="tocline">
+          <a href="#obtaining-networked-services"
+              class="tocxref"><span class="secno">6.</span> Obtaining networked services</a>
+          <ul class="toc">
+            <li class="tocline">
+              <a href="#attributes"
+                  class="tocxref"><span class="secno">6.1</span> Attributes</a>
+            </li>
+            <li class="tocline">
+              <a href="#methods-1"
+                  class="tocxref"><span class="secno">6.2</span> Methods</a>
+            </li>
+            <li class="tocline">
+              <a href="#events"
+                  class="tocxref"><span class="secno">6.3</span> Events</a>
+            </li>
+          </ul>
+        </li>
+        <li class="tocline">
+          <a href="#communicating-with-a-networked-service"
+              class="tocxref"><span class="secno">7.</span> Communicating with a networked service</a>
+          <ul class="toc">
+            <li class="tocline">
+              <a href="#attributes-1"
+                  class="tocxref"><span class="secno">7.1</span> Attributes</a>
+            </li>
+            <li class="tocline">
+              <a href="#states"
+                  class="tocxref"><span class="secno">7.2</span> States</a>
+            </li>
+            <li class="tocline">
+              <a href="#events-1"
+                  class="tocxref"><span class="secno">7.3</span> Events</a>
+            </li>
+          </ul>
+        </li>
+        <li class="tocline">
+          <a href="#service-discovery"
+              class="tocxref"><span class="secno">8.</span> Service Discovery</a>
+          <ul class="toc">
+            <li class="tocline">
+              <a href="#zeroconf-mdns-dns-sd"
+                  class="tocxref"><span class="secno">8.1</span> Zeroconf (<abbr title="Multicast DNS">mDNS</abbr> +
+                  <abbr title="Domain Name System">DNS</abbr>-<abbr title="Service Discovery">SD</abbr>)</a>
+            </li>
+            <li class="tocline">
+              <a href="#simple-service-discovery-protocol-ssdp"
+                  class="tocxref"><span class="secno">8.2</span> Simple Service Discovery Protocol (<abbr title=
+                  "Simple Service Discovery Protocol">SSDP</abbr>)</a>
+            </li>
+            <li class="tocline">
+              <a href="#discovery-and-launch-protocol-dial"
+                  class="tocxref"><span class="secno">8.3</span> Discovery and Launch Protocol (<abbr title=
+                  "Discovery and Launch Protocol">DIAL</abbr>)</a>
+            </li>
+            <li class="tocline">
+              <a href="#network-topology-monitoring"
+                  class="tocxref"><span class="secno">8.4</span> Network Topology Monitoring</a>
+            </li>
+          </ul>
+        </li>
+        <li class="tocline">
+          <a href="#events-summary"
+              class="tocxref"><span class="secno">9.</span> Events Summary</a>
+        </li>
+        <li class="tocline">
+          <a href="#garbage-collection"
+              class="tocxref"><span class="secno">10.</span> Garbage collection</a>
+        </li>
+        <li class="tocline">
+          <a href="#use-cases-and-requirements"
+              class="tocxref"><span class="secno">11.</span> Use Cases and Requirements</a>
+        </li>
+        <li class="tocline">
+          <a href="#examples"
+              class="tocxref"><span class="secno">A.</span> Examples</a>
+        </li>
+        <li class="tocline">
+          <a href="#acknowledgements"
+              class="tocxref"><span class="secno">B.</span> Acknowledgements</a>
+        </li>
+        <li class="tocline">
+          <a href="#references"
+              class="tocxref"><span class="secno">C.</span> References</a>
+          <ul class="toc">
+            <li class="tocline">
+              <a href="#normative-references"
+                  class="tocxref"><span class="secno">C.1</span> Normative references</a>
+            </li>
+            <li class="tocline">
+              <a href="#informative-references"
+                  class="tocxref"><span class="secno">C.2</span> Informative references</a>
+            </li>
+          </ul>
+        </li>
+      </ul>
+    </section>
+    <section class="informative"
+             id="introduction">
+      <h2 aria-level="1"
+          role="heading"
+          id="h2_introduction">
+        <span class="secno">1.</span> Introduction
+      </h2>
+      <p>
+        <em>This section is non-normative.</em>
+      </p>
+      <p>
+        This specification defines the <a href="#navigatornetworkservice"><code>NavigatorNetworkService</code></a>
+        interface to enable Web pages to connect and communicate with Local-networked Services provided over
+        <abbr title="Hypertext Transfer Protocol">HTTP</abbr>. This enables access to services and content provided by
+        home network devices, including the discovery and playback of content available to those devices, both from
+        services such as traditional broadcast media and internet based services as well as local services. Initial
+        design goals and requirements provided by the <a href="http://www.w3.org/2011/webtv/"><abbr title=
+        "World Wide Web Consortium">W3C</abbr> Web &amp; TV interest group</a> are documented in [<cite><a class=
+        "bibref"
+           href="#bib-hnreq">hnreq</a></cite>].
+      </p>
+      <p>
+        Using this <abbr title="Application Programming Interface">API</abbr> consists of requesting a well-known
+        service type, known by developers and advertised by Local-networked Devices. User authorization, where the user
+        connects the web page to discovered services, is expected before the web page is able to interact with any
+        Local-networked Services.
+      </p>
+      <p>
+        A web page creates a request to obtain connectivity to services running in the network by specifying a
+        well-known discovery service type that it wishes to interact with.
+      </p>
+      <p>
+        The user agent, having captured all advertised services on the network from the <a href=
+        "#dfn-service-discovery-mechanisms"
+           class="internalDFN">service discovery mechanisms</a> included in this recommendation, attempts to match the
+           requested service type to a discovered service according to the processing described herein. Only
+           Local-networked Services that pass a <a href="#dfn-preliminary-cors-check"
+           class="internalDFN">preliminary CORS check</a> should be made available to web pages by a user agent. A user
+           agent may provide a way for users to white-list non-CORS enabled Local-networked Services but implementation
+           of such a feature is left to the discretion of the implementer.
+      </p>
+      <p>
+        If a service connectivity request is successful then the Web page is provided with a promise-based success
+        callback with the all necessary information to communicate with the authorized Local-networked Service. If the
+        request fails then the Web page will receive a promise-based error callback containing an error string
+        describing the cause of Local-networked Service connectivity failure.
+      </p>
+      <p>
+        Once connected to a Local-networked Service the Web page can send requests and receive responses to the
+        Local-networked Service via the messaging format and appropriate channel inferred from the service type
+        authorized via the provided <abbr title="Application Programming Interface">API</abbr>. The Web page, once
+        connected, can also receive service-pushed events, in the messaging format supported by the Local-networked
+        Device, if such event subscription functionality is provided by the connected Local-networked Service.
+      </p>
+      <p>
+        Services available within the local network can connect and disconnect at different times during the execution
+        of a web page. The user agent can inform a web page when the state of networked services matching any of the
+        requested valid service types change. Web pages can use this information to enable in-page experiences for
+        communicating the state of networked services with the ability to change the particular service or set of
+        services the page is connected to (by re-invoking the <a href=
+        "#dom-navigator-getnetworkservices"><code>getNetworkServices()</code></a> method defined herein).
+      </p>
+      <div class="example">
+        <p>
+          Example of requesting a <abbr title="Domain Name System">DNS</abbr>-<abbr title="Service Discovery">SD</abbr>
+          advertised service:
+        </p>
+        <hr>
+        <pre class="highlight prettyprint prettyprinted"
+             style="">
+<span class="kwd">function</span><span class="pln"> showServices</span><span class="pun">(</span><span class=
+"pln"> services </span><span class="pun">)</span><span class="pln"> </span><span class="pun">{</span><span class="pln">
+  </span><span class="com">// Show a list of all the services provided to the web page</span><span class="pln">
+  </span><span class="kwd">for</span><span class="pun">(</span><span class="kwd">var</span><span class=
+"pln"> i </span><span class="pun">=</span><span class="pln"> </span><span class="lit">0</span><span class=
+"pun">,</span><span class="pln"> l </span><span class="pun">=</span><span class="pln"> services</span><span class=
+"pun">.</span><span class="pln">length</span><span class="pun">;</span><span class="pln"> i </span><span class=
+"pun">&lt;</span><span class="pln"> l</span><span class="pun">;</span><span class="pln"> i</span><span class=
+"pun">++)</span><span class="pln"> console</span><span class="pun">.</span><span class="pln">log</span><span class=
+"pun">(</span><span class="pln"> services</span><span class="pun">[</span><span class="pln">i</span><span class=
+"pun">].</span><span class="pln">name </span><span class="pun">);</span><span class="pln">
+</span><span class="pun">}</span><span class="pln">
+
+navigator</span><span class="pun">.</span><span class="pln">getNetworkServices</span><span class=
+"pun">(</span><span class="str">'zeroconf:_boxee-jsonrpc._tcp'</span><span class="pun">).</span><span class=
+"kwd">then</span><span class="pun">(</span><span class="pln">showServices</span><span class="pun">);</span>
+</pre>
+      </div>
+      <div class="example">
+        <p>
+          Example of requesting a UPnP advertised service, also handling error conditions:
+        </p>
+        <hr>
+        <pre class="highlight prettyprint prettyprinted"
+             style="">
+<span class="kwd">function</span><span class="pln"> showServices</span><span class="pun">(</span><span class=
+"pln"> services </span><span class="pun">)</span><span class="pln"> </span><span class="pun">{</span><span class="pln">
+  </span><span class="com">// Show a list of all the services provided to the web page</span><span class="pln">
+  </span><span class="kwd">for</span><span class="pun">(</span><span class="kwd">var</span><span class=
+"pln"> i </span><span class="pun">=</span><span class="pln"> </span><span class="lit">0</span><span class=
+"pun">,</span><span class="pln"> l </span><span class="pun">=</span><span class="pln"> services</span><span class=
+"pun">.</span><span class="pln">length</span><span class="pun">;</span><span class="pln"> i </span><span class=
+"pun">&lt;</span><span class="pln"> l</span><span class="pun">;</span><span class="pln"> i</span><span class=
+"pun">++)</span><span class="pln"> console</span><span class="pun">.</span><span class="pln">log</span><span class=
+"pun">(</span><span class="pln"> services</span><span class="pun">[</span><span class="pln">i</span><span class=
+"pun">].</span><span class="pln">name </span><span class="pun">);</span><span class="pln">
+</span><span class="pun">}</span><span class="pln">
+
+</span><span class="kwd">function</span><span class="pln"> error</span><span class="pun">(</span><span class=
+"pln"> e </span><span class="pun">)</span><span class="pln"> </span><span class="pun">{</span><span class="pln">
+  console</span><span class="pun">.</span><span class="pln">log</span><span class="pun">(</span><span class=
+"pln"> </span><span class="str">"Error occurred: "</span><span class="pln"> </span><span class=
+"pun">+</span><span class="pln"> e</span><span class="pun">.</span><span class="pln">name </span><span class=
+"pun">);</span><span class="pln">
+</span><span class="pun">}</span><span class="pln">
+
+navigator</span><span class="pun">.</span><span class="pln">getNetworkServices</span><span class=
+"pun">(</span><span class="str">'upnp:urn:schemas-upnp-org:service:ContentDirectory:1'</span><span class=
+"pun">).</span><span class="kwd">then</span><span class="pun">(</span><span class="pln">showServices</span><span class=
+"pun">,</span><span class="pln"> error</span><span class="pun">);</span>
+</pre>
+      </div>
+      <div class="example">
+        <p>
+          Example of requesting either a <abbr title="Domain Name System">DNS</abbr>-<abbr title=
+          "Service Discovery">SD</abbr> or UPnP advertised service:
+        </p>
+        <hr>
+        <pre class="highlight prettyprint prettyprinted"
+             style="">
+<span class="kwd">function</span><span class="pln"> showServices</span><span class="pun">(</span><span class=
+"pln"> services </span><span class="pun">)</span><span class="pln"> </span><span class="pun">{</span><span class="pln">
+  </span><span class=
+"com">// Show a list of all the services provided to the web page (+ service type)</span><span class="pln">
+  </span><span class="kwd">for</span><span class="pun">(</span><span class="kwd">var</span><span class=
+"pln"> i </span><span class="pun">=</span><span class="pln"> </span><span class="lit">0</span><span class=
+"pun">,</span><span class="pln"> l </span><span class="pun">=</span><span class="pln"> services</span><span class=
+"pun">.</span><span class="pln">length</span><span class="pun">;</span><span class="pln"> i </span><span class=
+"pun">&lt;</span><span class="pln"> l</span><span class="pun">;</span><span class="pln"> i</span><span class=
+"pun">++)</span><span class="pln">
+     console</span><span class="pun">.</span><span class="pln">log</span><span class="pun">(</span><span class=
+"pln"> services</span><span class="pun">[</span><span class="pln">i</span><span class="pun">].</span><span class=
+"pln">name </span><span class="pun">+</span><span class="pln"> </span><span class="str">'('</span><span class=
+"pln"> </span><span class="pun">+</span><span class="pln"> services</span><span class="pun">[</span><span class=
+"pln">i</span><span class="pun">].</span><span class="pln">type </span><span class="pun">+</span><span class=
+"pln"> </span><span class="str">')'</span><span class="pln"> </span><span class="pun">);</span><span class="pln">
+</span><span class="pun">}</span><span class="pln">
+
+navigator</span><span class="pun">.</span><span class="pln">getNetworkServices</span><span class=
+"pun">([</span><span class="pln">
+  </span><span class="str">'zeroconf:_boxee-jsonrpc._tcp'</span><span class="pun">,</span><span class="pln">
+  </span><span class="str">'upnp:urn:schemas-upnp-org:service:ContentDirectory:1'</span><span class="pln">
+</span><span class="pun">]).</span><span class="kwd">then</span><span class="pun">(</span><span class=
+"pln">showServices</span><span class="pun">);</span>
+</pre>
+      </div>
+      <p>
+        For more detailed examples, including examples of communicating with obtained networked services, see the
+        <a href="#examples">Examples</a> section.
+      </p>
+    </section>
+    <section id="conformance"
+             typeof="bibo:Chapter"
+             resource="#ref"
+             rel="bibo:Chapter">
+      <h2 aria-level="1"
+          role="heading"
+          id="h2_conformance">
+        <span class="secno">2.</span> Conformance
+      </h2>
+      <p>
+        As well as sections marked as non-normative, all authoring guidelines, diagrams, examples, and notes in this
+        specification are non-normative. Everything else in this specification is normative.
+      </p>
+      <p>
+        The key words <em class="rfc2119"
+           title="MUST">MUST</em>, <em class="rfc2119"
+           title="MUST NOT">MUST NOT</em>, <em class="rfc2119"
+           title="REQUIRED">REQUIRED</em>, <em class="rfc2119"
+           title="SHOULD">SHOULD</em>, <em class="rfc2119"
+           title="SHOULD NOT">SHOULD NOT</em>, <em class="rfc2119"
+           title="RECOMMENDED">RECOMMENDED</em>, <em class="rfc2119"
+           title="MAY">MAY</em>, and <em class="rfc2119"
+           title="OPTIONAL">OPTIONAL</em> in this specification are to be interpreted as described in [<cite><a class=
+           "bibref"
+           href="#bib-RFC2119">RFC2119</a></cite>].
+      </p>
+      <p>
+        Requirements phrased in the imperative as part of algorithms (such as "strip any leading space characters" or
+        "return false and abort these steps") are to be interpreted with the meaning of the key word ("must", "should",
+        "may", etc) used in introducing the algorithm.
+      </p>
+      <p>
+        Some conformance requirements are phrased as requirements on attributes, methods or objects. Such requirements
+        are to be interpreted as requirements on user agents.
+      </p>
+      <p>
+        Conformance requirements phrased as algorithms or specific steps <em class="rfc2119"
+           title="MAY">MAY</em> be implemented in any manner, so long as the end result is equivalent. (In particular,
+           the algorithms defined in this specification are intended to be easy to follow, and not intended to be
+           performant.)
+      </p>
+      <p>
+        The only conformance class defined by this specification is a <dfn id="dfn-user-agent">user agent</dfn>.
+      </p>
+      <p>
+        User agents <em class="rfc2119"
+           title="MAY">MAY</em> impose implementation-specific limits on otherwise unconstrained inputs, e.g. to
+           prevent denial of service attacks, to guard against running out of memory, or to work around
+           platform-specific limitations.
+      </p>
+      <p>
+        When support for a feature is disabled (e.g. as an emergency measure to mitigate a security problem, or to aid
+        in development, or for performance reasons), user agents <em class="rfc2119"
+           title="MUST">MUST</em> act as if they had no support for the feature whatsoever, and as if the feature was
+           not mentioned in this specification. For example, if a particular feature is accessed via an attribute in a
+           Web IDL interface, the attribute itself would be omitted from the objects that implement that interface -
+           leaving the attribute on the object but making it return null or throw an exception is insufficient.
+      </p>
+      <section id="dependencies">
+        <h3 aria-level="2"
+            role="heading"
+            id="h3_dependencies">
+          <span class="secno">2.1</span> Dependencies
+        </h3>This specification relies on several other underlying specifications.
+        <dl>
+          <dt>
+            HTML
+          </dt>
+          <dd>
+            Many fundamental concepts from HTML are used by this specification. [<cite><a class="bibref"
+               href="#bib-HTML5">HTML5</a></cite>]
+          </dd>
+          <dt>
+            WebIDL
+          </dt>
+          <dd>
+            The IDL blocks in this specification use the semantics of the WebIDL specification. [<cite><a class=
+            "bibref"
+               href="#bib-WEBIDL">WEBIDL</a></cite>]
+          </dd>
+        </dl>
+      </section>
+    </section>
+    <section id="terminology">
+      <h2 aria-level="1"
+          role="heading"
+          id="h2_terminology">
+        <span class="secno">3.</span> Terminology
+      </h2>
+      <p>
+        The construction "a <code>Foo</code> object", where <code>Foo</code> is actually an interface, is sometimes
+        used instead of the more accurate "an object implementing the interface <code>Foo</code>".
+      </p>
+      <p>
+        The term DOM is used to refer to the <abbr title="Application Programming Interface">API</abbr> set made
+        available to scripts in Web applications, and does not necessarily imply the existence of an actual
+        <code>Document</code> object or of any other <code>Node</code> objects as defined in the DOM Core
+        specifications. [<cite><a class="bibref"
+           href="#bib-DOM4">DOM4</a></cite>]
+      </p>
+      <p>
+        An IDL attribute is said to be <em>getting</em> when its value is being retrieved (e.g. by author script), and
+        is said to be <em>setting</em> when a new value is assigned to it.
+      </p>
+      <p>
+        A <dfn id="dfn-valid-service-type">valid service type</dfn> is any of the following:
+      </p>
+      <ul>
+        <li>a string that begins with <code>upnp:</code> or <code>zeroconf:</code> followed by one or more characters
+        in the ranges U+0021, U+0023 to U+0027, U+002A to U+002B, U+002D to U+002E, U+0030 to U+0039, U+0041 to U+005A,
+        U+005E to U+007E.
+        </li>
+        <li>a string that begins with <code>dial:</code> followed by an integer version.
+        </li>
+      </ul>
+      <p>
+        A <a href="#dfn-valid-service-type"
+           class="internalDFN">valid service type</a> provided in the <code>type</code> attribute of the <a href=
+           "#dom-navigator-getnetworkservices"><code>getNetworkServices()</code></a> method will be matched against the
+           services currently contained in the <a href="#dfn-list-of-available-service-records"
+           class="internalDFN">list of available service records</a> according to the algorithms defined in this
+           specification.
+      </p>
+      <p>
+        A <dfn id="dfn-user-agent-generated-callback-url">user-agent generated callback url</dfn> is a Local-network
+        accessible URL endpoint that a <a href="#dfn-user-agent"
+           class="internalDFN">user agent</a> generates and maintains for receiving <abbr title=
+           "Hypertext Transfer Protocol">HTTP</abbr> NOTIFY requests from UPnP Event sources. It is only required when
+           the user agent implements UPnP Service Discovery as defined in this specification.
+      </p>
+      <p>
+        In this specification we use the following terms to describe the processes required for Local-networked
+        Services management:
+      </p>
+      <ul>
+        <li>A <dfn id="dfn-new-service">new service</dfn> is a Local-networked Service that has not previously been
+        discovered or registered in the <a href="#dfn-list-of-available-service-records"
+              class="internalDFN">list of available service records</a>.
+        </li>
+        <li>An <dfn id="dfn-existing-service">existing service</dfn> is a Local-networked Service that has previously
+        been discovered and is registered in the <a href="#dfn-list-of-available-service-records"
+              class="internalDFN">list of available service records</a>.
+        </li>
+        <li>A <dfn id="dfn-current-service">current service</dfn> is a Local-networked Service, represented by a
+        <a href="#networkservice"><code>NetworkService</code></a> object, that is currently being shared with a web
+        page via a <a href="#networkservices"><code>NetworkServices</code></a> object registered in the <a href=
+        "#dfn-list-of-active-service-managers"
+              class="internalDFN">list of active service managers</a>.
+        </li>
+      </ul>
+      <p>
+        A <dfn id="dfn-network-services-whitelist">network services whitelist</dfn> is a list of zero or more <a href=
+        "#dfn-valid-service-type"
+           class="internalDFN">valid service type</a> tokens that, when matched to a service type discovered in the
+           local network, enables that service to be shared with a web page even if that Local-networked Service does
+           not itself allow Cross-Origin Resource Sharing [<cite><a class="bibref"
+           href="#bib-CORS">CORS</a></cite>]. A <a href="#dfn-user-agent"
+           class="internalDFN">user agent</a> <em class="rfc2119"
+           title="MUST">MUST</em> simulate CORS support for all service interaction in this case. Implementation of
+           this feature is at implementer's discretion. When a <a href="#dfn-user-agent"
+           class="internalDFN">user agent</a> does not implement a <a href="#dfn-network-services-whitelist"
+           class="internalDFN">network services whitelist</a> then it is to treat this as always being an empty list.
+      </p>
+    </section>
+    <section id="security-and-privacy-considerations">
+      <h2 aria-level="1"
+          role="heading"
+          id="h2_security-and-privacy-considerations">
+        <span class="secno">4.</span> Security and privacy considerations
+      </h2>
+      <p>
+        The <abbr title="Application Programming Interface">API</abbr> defined in this specification can be used to
+        find and connect to devices and services within a user's current network. This discloses information related to
+        a user's network: devices available on their network and the publicly-accessible services ("networked
+        services") currently running and available on those devices. The distribution of this information could
+        potentially compromise the user's privacy. A conforming implementation of this specification <em class=
+        "rfc2119"
+           title="MUST">MUST</em> provide a mechanism that protects the user's privacy. This mechanism <em class=
+           "rfc2119"
+           title="MUST">MUST</em> ensure that no networked service information is retrievable without the user's
+           express permission.
+      </p>
+      <section id="security-considerations-for-api-implementations">
+        <h3 aria-level="2"
+            role="heading"
+            id="h3_security-considerations-for-api-implementations">
+          <span class="secno">4.1</span> Security considerations for <abbr title=
+          "Application Programming Interface">API</abbr> implementations
+        </h3>
+        <p>
+          A <a href="#dfn-user-agent"
+             class="internalDFN">user agent</a> <em class="rfc2119"
+             title="SHOULD">SHOULD</em> only allow web pages to connect with Local-networked Services that have passed
+             a <a href="#dfn-preliminary-cors-check"
+             class="internalDFN">preliminary CORS check</a> indicating they support Cross-Origin Resource Sharing
+             [<cite><a class="bibref"
+             href="#bib-CORS">CORS</a></cite>]. In this way, a <a href="#dfn-user-agent"
+             class="internalDFN">user agent</a> <em class="rfc2119"
+             title="SHOULD NOT">SHOULD NOT</em> allow web pages to access other arbitrary networked services on the
+             current local network.
+        </p>
+        <p>
+          A <a href="#dfn-user-agent"
+             class="internalDFN">user agent</a> <em class="rfc2119"
+             title="MAY">MAY</em> provide a way for users to enable access to non-CORS enabled Local-networked Services
+             from web pages (i.e. operate a <a href="#dfn-network-services-whitelist"
+             class="internalDFN">network services whitelist</a>). Implementation of such a <a href=
+             "#dfn-network-services-whitelist"
+             class="internalDFN">network services whitelist</a>, if any, is left to an implementer's discretion. Such a
+             whitelist may be configurable by each user at runtime or may be managed by the implementation itself on
+             behalf of its users. In the case that a <a href="#dfn-user-agent"
+             class="internalDFN">user agent</a> provides a <a href="#dfn-network-services-whitelist"
+             class="internalDFN">network services whitelist</a>, it <em class="rfc2119"
+             title="MUST">MUST</em> act as if all URLs for the Local-networked Service corresponding to any previously
+             whitelisted service type had Cross-Origin Resource Sharing [<cite><a class="bibref"
+             href="#bib-CORS">CORS</a></cite>] enabled indefinitely.
+        </p>
+      </section>
+      <section id="privacy-considerations-for-api-implementations">
+        <h3 aria-level="2"
+            role="heading"
+            id="h3_privacy-considerations-for-api-implementations">
+          <span class="secno">4.2</span> Privacy considerations for <abbr title=
+          "Application Programming Interface">API</abbr> implementations
+        </h3>
+        <p>
+          A <a href="#dfn-user-agent"
+             class="internalDFN">user agent</a> <em class="rfc2119"
+             title="MUST NOT">MUST NOT</em> provide networked service information to web sites without the express
+             permission of the user. A user agent <em class="rfc2119"
+             title="MUST">MUST</em> acquire permission through a user interface, unless they have prearranged trust
+             relationships with users, as described below. The user interface <em class="rfc2119"
+             title="MUST">MUST</em> include the document base URL. Those permissions that are acquired through the user
+             interface and that are preserved beyond the current browsing session (i.e. beyond the time when the
+             browsing context is navigated to another URL) <em class="rfc2119"
+             title="MUST">MUST</em> be revocable and a user agent <em class="rfc2119"
+             title="MUST">MUST</em> respect revoked permissions.
+        </p>
+        <p>
+          Obtaining the user's express permission to access one <abbr title=
+          "Application Programming Interface">API</abbr> method does not imply the user has granted permission for the
+          same web site to access any other methods that may be provided by this <abbr title=
+          "Application Programming Interface">API</abbr>, or to access the same method with a different set of
+          arguments, as part of the same permission context. If a user has expressed permission for an implementation
+          to, e.g. find a set of existing networked services, the implementation <em class="rfc2119"
+             title="MUST">MUST</em> seek the user's express permission if and when any subsequent functions are called
+             on this <abbr title="Application Programming Interface">API</abbr>.
+        </p>
+        <p>
+          A user agent <em class="rfc2119"
+             title="MAY">MAY</em> have prearranged trust relationships that do not require such user interfaces. For
+             example, while a web browser will present a user interface when a web site performs a networked service
+             lookup, a different runtime may have a prearranged, delegated security relationship with the user and, as
+             such, a suitable alternative security and privacy mechanism with which to authorise the retrieval of
+             networked service information.
+        </p>
+      </section>
+      <section class="informative"
+               id="additional-api-implementation-considerations">
+        <h3 aria-level="2"
+            role="heading"
+            id="h3_additional-api-implementation-considerations">
+          <span class="secno">4.3</span> Additional <abbr title="Application Programming Interface">API</abbr>
+          implementation considerations
+        </h3>
+        <p>
+          <em>This section is non-normative.</em>
+        </p>
+        <p>
+          Further to the requirements listed in the previous section, implementers of the Network Service Discovery
+          <abbr title="Application Programming Interface">API</abbr> are also advised to consider the following aspects
+          that can negatively affect the privacy of their users: in certain cases, users can inadvertently grant
+          permission to the user agent to disclose networked services to Web sites. In other cases, the content hosted
+          at a certain URL changes in such a way that previously granted networked service permissions no longer apply
+          as far as the user is concerned. Or the users might simply change their minds.
+        </p>
+        <p>
+          Predicting or preventing these situations is inherently difficult. Mitigation and in-depth defensive measures
+          are an implementation responsibility and not prescribed by this specification. However, in designing these
+          measures, implementers are advised to enable user awareness of networked service sharing, and to provide easy
+          access to interfaces that enable revocation of permissions that web applications have for accessing networked
+          services via this <abbr title="Application Programming Interface">API</abbr>.
+        </p>
+      </section>
+    </section>
+    <section id="requesting-networked-services">
+      <h2 aria-level="1"
+          role="heading"
+          id="h2_requesting-networked-services">
+        <span class="secno">5.</span> Requesting networked services
+      </h2>
+      <pre class="widl">
+[Supplemental, NoInterfaceObject]
+interface <dfn id="navigatornetworkservice">NavigatorNetworkService</dfn> {
+  <a class="externalDFN"
+     href="http://dom.spec.whatwg.org/#promise">Promise</a> <a href=
+     "#dom-navigator-getnetworkservices">getNetworkServices</a>( in any type );
+};
+
+<a class="externalDFN"
+     href=
+     "http://www.whatwg.org/specs/web-apps/current-work/complete/timers.html#navigator">Navigator</a> implements <a href=
+     "#navigatornetworkservice">NavigatorNetworkService</a>;
+</pre>
+      <section id="methods">
+        <h3 aria-level="2"
+            role="heading"
+            id="h3_methods">
+          <span class="secno">5.1</span> Methods
+        </h3>
+        <dl class="domintro">
+          <dt>
+            <var title="">promise</var> = <var title="">window</var> . <code title="dom-navigator"><a href=
+            "http://www.whatwg.org/specs/web-apps/current-work/complete/timers.html#navigator">navigator</a></code> .
+            <code title="dom-navigator-getNetworkServices"><a href=
+            "#dom-navigator-getnetworkservices">getNetworkServices</a></code> ( <var title="">type</var> )
+          </dt>
+          <dd>
+            <p>
+              Immediately returns a new <a href="http://dom.spec.whatwg.org/#promise"
+                 class="externalDFN">Promise</a> object and then the user is prompted to select discovered network
+                 services that have advertised support for the requested service type(s).
+            </p>
+            <p>
+              The <var title="">type</var> argument contains one or more <a href="#dfn-valid-service-type"
+                 class="internalDFN">valid service type</a> tokens that the web page would like to interact with.
+            </p>
+            <p>
+              If the user accepts, the <var title="">promise</var> object is <a class="externalDFN"
+                 href="http://dom.spec.whatwg.org/#concept-resolver-resolve">resolved</a>, with a <a href=
+                 "#networkservices"><code>NetworkServices</code></a> object as its argument.
+            </p>
+            <p>
+              If the user declines, or an error occurs, the <var title="">promise</var> object is <a class=
+              "externalDFN"
+                 href="http://dom.spec.whatwg.org/#concept-resolver-reject">rejected</a>.
+            </p>
+          </dd>
+        </dl>
+        <div>
+          <p>
+            When the <dfn id="dom-navigator-getnetworkservices"
+               title="dom-navigator-getnetworkservices"><code>getNetworkServices(type)</code></dfn> method is called,
+               the <a href="#dfn-user-agent"
+               class="internalDFN">user agent</a> <em class="rfc2119"
+               title="MUST">MUST</em> run the following steps:
+          </p>
+          <ol class="rule">
+            <li>Let <var>Network Service Promise</var> be a new <a href="http://dom.spec.whatwg.org/#promise"
+                  class="externalDFN"><code>Promise</code></a> object.
+            </li>
+            <li>Let <var>Network Service Promise's Resolver</var> be the default <a href=
+            "http://dom.spec.whatwg.org/#concept-resolver"
+                  class="externalDFN">resolver</a> of <var>Network Service Promise</var>.
+            </li>
+            <li>Return <var>Network Service Promise</var>, and run the remaining steps asynchronously.
+            </li>
+            <li>Let <var>requested control types</var> be initially set to an empty array.
+            </li>
+            <li>If <var>type</var> is an array consisting of one or more <a href="#dfn-valid-service-type"
+                  class="internalDFN">valid service type</a> tokens, then let <var>requested control types</var> be the
+                  value of <var>type</var>, removing any non-<a href="#dfn-valid-service-type"
+                  class="internalDFN">valid service type</a> tokens from the resulting array.
+            </li>
+            <li>If <var>type</var> is a string consisting of one <a href="#dfn-valid-service-type"
+                  class="internalDFN">valid service type</a> token, then let <var>requested control types</var> be an
+                  array containing one item with a value of <var>type</var>.
+            </li>
+            <li>If <var>requested control types</var> is an array that contains at least one or more <a title=
+            "valid service type"
+                  href="#dfn-valid-service-type"
+                  class="internalDFN">valid service type</a> tokens then continue to the step labeled <em>process</em>
+                  below. Otherwise, reject <var>Network Service Promise</var> by running the <a href=
+                  "http://dom.spec.whatwg.org/#concept-resolver-reject"
+                  class="externalDFN">resolver reject algorithm</a> against the <var>Network Service Promise's
+                  Resolver</var>, passing in a newly constructed <a href="http://dom.spec.whatwg.org/#domerror"
+                  class="externalDFN"><code>DOMError</code></a> object whose <code>name</code> attribute has the string
+                  value "UnknownTypePrefixError" (<a href=
+                  "#dom-domerror-extensions-unknown_type_prefix"><code>UNKNOWN_TYPE_PREFIX_ERR</code></a>) and whose
+                  <code>message</code> attribute has a helpful implementation-dependent message that explains this
+                  error, abort any remaining steps and return.
+            </li>
+            <li>
+              <em>Process</em>: Let <var>services found</var> be an empty array.
+            </li>
+            <li>For each <var>available service</var> in the <a href="#dfn-list-of-available-service-records"
+                  class="internalDFN">list of available service records</a> run the following steps:
+              <ol class="rule">
+                <li>For each <var>requested control type</var> in <var>requested control types</var>: If <var>available
+                service</var>'s <code>type</code> attribute equals the <var>requested control type</var> then let <var>
+                  matched service</var> equal the value of <var>available service</var>. Otherwise, abort the remaining
+                  sub-steps and continue above at the next <var>available service</var>.
+                </li>
+                <li>If <var>matched service</var> is not empty then run the following steps:
+                  <ol class="rule">
+                    <li>Let <var>CORS check result</var> be the result of running the <a href=
+                    "#dfn-preliminary-cors-check"
+                          class="internalDFN">preliminary CORS check</a> algorithm, passing in <var>matched
+                          services</var>'s <code>url</code> attribute as the <var>control endpoint URL</var> argument
+                          and the <a href=
+                          "http://www.whatwg.org/specs/web-apps/current-work/complete/browsers.html#entry-script"
+                          class="externalDFN">entry script</a>'s <a href=
+                          "http://www.whatwg.org/specs/web-apps/current-work/complete/origin-0.html#origin"
+                          class="externalDFN">origin</a> as the <var>request origin</var> argument.
+                    </li>
+                    <li>If <var>CORS check result</var> is not <code>pass</code> and <var>matched service</var>'s
+                    <code>type</code> attribute is also not present in the <a href="#dfn-network-services-whitelist"
+                          class="internalDFN">network services whitelist</a> then abort the remaining sub-steps and
+                          continue above at the next <var>available service</var>.
+                    </li>
+                    <li>Let <var>new service object</var> be a new <a href=
+                    "#networkservice"><code>NetworkService</code></a> object, mapping the parameters of <var>matched
+                    service</var> to this new object where possible.
+                    </li>
+                    <li>Append <var>new service object</var> to the <var>services found</var> array.
+                    </li>
+                  </ol>
+                </li>
+              </ol>
+            </li>
+            <li>Optionally, e.g. based on a previously-established user preference, for security reasons, or due to
+            platform limitations, the <a href="#dfn-user-agent"
+                  class="internalDFN">user agent</a> <em class="rfc2119"
+                  title="MAY">MAY</em> reject <var>Network Service Promise</var> by running the <a href=
+                  "http://dom.spec.whatwg.org/#concept-resolver-reject"
+                  class="externalDFN">resolver reject algorithm</a> against the <var>Network Service Promise's
+                  Resolver</var>, passing in a newly constructed <a href="http://dom.spec.whatwg.org/#domerror"
+                  class="externalDFN"><code>DOMError</code></a> object whose <code>name</code> attribute has the string
+                  value "PermissionDeniedError" (<a href=
+                  "#dom-domerror-extensions-permission_denied"><code>PERMISSION_DENIED_ERR</code></a>) and whose
+                  <code>message</code> attribute has a helpful implementation-dependent message that explains this
+                  error, abort any remaining steps and return.
+            </li>
+            <li>The user agent <em class="rfc2119"
+                  title="MUST NOT">MUST NOT</em> provide the entry script's origin with a <a href=
+                  "#networkservices"><code>NetworkServices</code></a> object without prior permission given by the
+                  user.
+              <p>
+                If <var>services found</var> is not an empty array then the <a href="#dfn-user-agent"
+                   class="internalDFN">user agent</a> <em class="rfc2119"
+                   title="MAY">MAY</em> choose to prompt the user in a user-agent-specific manner for permission to
+                   provide the <a href=
+                   "http://www.whatwg.org/specs/web-apps/current-work/complete/browsers.html#entry-script"
+                   class="externalDFN">entry script</a>'s <a href=
+                   "http://www.whatwg.org/specs/web-apps/current-work/complete/origin-0.html#origin"
+                   class="externalDFN">origin</a> with a <a href="#networkservices"><code>NetworkServices</code></a>
+                   object representing the <a href="#dfn-user-authorized"
+                   class="internalDFN">user-authorized</a> subset of <var>services found</var>.
+              </p>
+              <p>
+                Alternatively, the user agent <em class="rfc2119"
+                   title="MAY">MAY</em> wish to skip this user opt-in step and choose to fulfill <var>Network Service
+                   Promise</var> immediately based on a previously-established user preference, for security reasons,
+                   or due to platform limitations. In such an implementation, if <var>Network Service Promise</var> is
+                   to be fulfilled as a result of a previously-established user preference then the <a href=
+                   "#dfn-user-agent"
+                   class="internalDFN">user agent</a> <em class="rfc2119"
+                   title="MUST">MUST</em> continue at the next step of this algorithm.
+              </p>
+              <p>
+                If permission has been granted by the user to access one or more networked services then the <a href=
+                "#dfn-user-agent"
+                   class="internalDFN">user agent</a> <em class="rfc2119"
+                   title="SHOULD">SHOULD</em> include an "ongoing local-network communication" indicator.
+              </p>
+              <p>
+                If permission has been denied by the user, <a href="#dfn-user-agent"
+                   class="internalDFN">user agent</a> or platform, then the <a href="#dfn-user-agent"
+                   class="internalDFN">user agent</a> <em class="rfc2119"
+                   title="MUST">MUST</em> reject <var>Network Service Promise</var> by running the <a href=
+                   "http://dom.spec.whatwg.org/#concept-resolver-reject"
+                   class="externalDFN">resolver reject algorithm</a> against the <var>Network Service Promise's
+                   Resolver</var>, passing in a newly constructed <a href="http://dom.spec.whatwg.org/#domerror"
+                   class="externalDFN"><code>DOMError</code></a> object whose <code>name</code> attribute has the
+                   string value "PermissionDeniedError" (<a href=
+                   "#dom-domerror-extensions-permission_denied"><code>PERMISSION_DENIED_ERR</code></a>) and whose
+                   <code>message</code> attribute has a helpful implementation-dependent message that explains this
+                   error, abort any remaining steps and return.
+              </p>
+              <p>
+                If the user never responds or no previously-established user preference has been met, this algorithm
+                stalls on this step.
+              </p>
+            </li>
+            <li>Let <var>services</var> be an empty array.
+            </li>
+            <li>If <var>services found</var> is not an empty array then set <var>services</var> to be an array of one
+            or more <a href="#networkservice"><code>NetworkService</code></a> objects for which the user granted
+            permission above - known as the current objects <dfn id="dfn-user-authorized">user-authorized</dfn>
+            services.
+            </li>
+            <li>For each Object <var>service</var> in <var>services</var>, if any, run the following sub-steps:
+              <ol class="rule">
+                <li>If <var>service</var>'s <code>type</code> parameter begins with the DOMString "<code>upnp:</code>"
+                and the <var>service</var>'s <code>eventsUrl</code> parameter is not empty then <a href=
+                "#dfn-setup-a-upnp-events-subscription"
+                      class="internalDFN">setup a UPnP Events Subscription</a> for <var>service</var>.
+                </li>
+              </ol>
+            </li>
+            <li>Let <var>services manager</var> be a new <a href="#networkservices"><code>NetworkServices</code></a>
+            object.
+            </li>
+            <li>Store <var>requested control types</var> against <var>services manager</var> as an internal variable.
+            </li>
+            <li>Set <var>services manager</var>'s <a href=
+            "#dom-networkservices-servicesavailable"><code>servicesAvailable</code></a> attribute to the number of
+            items currently found in the <a href="#dfn-list-of-available-service-records"
+                  class="internalDFN">list of available service records</a> whose <code>type</code> property matches
+                  any of the tokens requested in <var>requested control types</var>.
+            </li>
+            <li>Add <var>services</var>, if any, to the <var>services manager</var> object as its collection of
+              <a href="#dfn-indexed-properties"
+                  class="internalDFN">indexed properties</a>. If <var>services</var> is an empty array then the
+                  <var>services manager</var> does not have any <var>indexed properties</var>.
+            </li>
+            <li>Set <var>services manager</var>'s <a href="#dom-networkservices-length"><code>length</code></a>
+            attribute to the number of items in <var>services</var>.
+            </li>
+            <li>Add <var>services manager</var> to the <a href="#dfn-list-of-active-service-managers"
+                  class="internalDFN">list of active service managers</a>.
+            </li>
+            <li>The <a href="#dfn-user-agent"
+                  class="internalDFN">user agent</a> <em class="rfc2119"
+                  title="MUST">MUST</em> fulfill <var>Network Service Promise</var> by running the <a href=
+                  "http://dom.spec.whatwg.org/#concept-resolver-fulfill"
+                  class="externalDFN">resolver fulfill algorithm</a> against the <var>Network Service Promise's
+                  Resolver</var>, passing in <var>services manager</var> as its argument.
+            </li>
+          </ol>
+          <p>
+            The <a href="http://www.whatwg.org/specs/web-apps/current-work/complete/webappapis.html#task-source"
+               class="externalDFN">task source</a> for these <a href=
+               "http://www.whatwg.org/specs/web-apps/current-work/complete/webappapis.html#concept-task"
+               class="externalDFN">tasks</a> is the <a href=
+               "http://www.whatwg.org/specs/web-apps/current-work/complete/webappapis.html#user-interaction-task-source"
+               class="externalDFN">user interaction task source</a>.
+          </p>
+          <p>
+            The <dfn id="dfn-preliminary-cors-check">preliminary CORS check</dfn> algorithm determines whether a
+            Local-networked Service supports Cross-Origin Resource Sharing [<cite><a class="bibref"
+               href="#bib-CORS">CORS</a></cite>] as part of a call to the <a href=
+               "#dom-navigator-getnetworkservices"><code>getNetworkServices()</code></a> method, prior to that service
+               being proposed for sharing to users and prior to active sharing with web pages. This algorithm takes two
+               arguments, <var>control endpoint URL</var> and <var>request origin</var>, and consists of running the
+               following steps:
+          </p>
+          <ol class="rule">
+            <li>Let <var>CORS available check</var> be the result of applying the <a href=
+            "http://www.w3.org/TR/cors/#make-a-request-steps"
+                  class="externalDFN">make a request steps</a> [<cite><a class="bibref"
+                 href="#bib-CORS">CORS</a></cite>], setting the <a href="http://www.w3.org/TR/cors/#request-method"
+                  class="externalDFN">request method</a> to <code>OPTIONS</code>, the <a href=
+                  "http://www.w3.org/TR/cors/#request-url"
+                  class="externalDFN">request URL</a> to <var>control endpoint URL</var>, the <a href=
+                  "http://www.w3.org/TR/cors/#source-origin"
+                  class="externalDFN">source origin</a> to <var>request origin</var>, setting the <a href=
+                  "http://www.w3.org/TR/cors/#omit-credentials-flag"
+                  class="externalDFN">omit credentials flag</a> to <code>true</code> and including an <a href=
+                  "http://www.w3.org/TR/cors/#http-access-control-request-method"
+                  class="externalDFN"><code>Access-Control-Request-Method</code></a> header with a value of
+                  <code>GET</code>.
+            </li>
+            <li>If <var>CORS available check</var> is cancelled by the user, or it results in a network error, or its
+            response does not have an <abbr title="Hypertext Transfer Protocol">HTTP</abbr> status code of
+            <code>200</code> then abort any remaining steps and return <code>fail</code>.
+            </li>
+            <li>Return the result of running the <a href="http://www.w3.org/TR/cors/#resource-sharing-check"
+                  class="externalDFN">resource sharing check</a> [<cite><a class="bibref"
+                 href="#bib-CORS">CORS</a></cite>] against the successful <abbr title=
+                 "Hypertext Transfer Protocol">HTTP</abbr> response of the <var>CORS available check</var>.
+              <div class="note">
+                <div class="note-title"
+                     aria-level="3"
+                     role="heading"
+                     id="h_note_1">
+                  <span>Note</span>
+                </div>
+                <p class="">
+                  This returned result will always be either <code>pass</code> or <code>fail</code>.
+                </p>
+              </div>
+            </li>
+          </ol>
+          <p>
+            There is no implied persistence to networked service sharing provided to a web page. It <em class="rfc2119"
+               title="MUST NOT">MUST NOT</em> be possible to access a networked service previously granted to a web
+               page without user authorization in all of the following cases:
+          </p>
+          <ul>
+            <li>If the current script is reloaded at any point in the same or different window.
+            </li>
+            <li>if the current script reinvokes the <a href=
+            "#dom-navigator-getnetworkservices"><code>getNetworkServices()</code></a> method at any point in its
+            execution.
+            </li>
+            <li>If the user navigates forward or back in their history to reload the current page.
+            </li>
+            <li>If a script is running in a different origin.
+            </li>
+          </ul>
+        </div>
+      </section>
+      <section id="error-handling">
+        <h3 aria-level="2"
+            role="heading"
+            id="h3_error-handling">
+          <span class="secno">5.2</span> Error Handling
+        </h3>
+        <dl class="domintro">
+          <dt>
+            <var title="">error</var> . <code title="dom-NavigatorNetworkServiceError-name"><a href=
+            "#dom-domerror-extensions-name">name</a></code>
+          </dt>
+          <dd>
+            <p>
+              Returns the current error's error name. At the current time, this will be "PermissionDeniedError" or
+              "UnknownTypePrefixError", for which the corresponding error constants <a href=
+              "#dom-domerror-extensions-permission_denied"><code>PERMISSION_DENIED_ERR</code></a> and <a href=
+              "#dom-domerror-extensions-unknown_type_prefix"><code>UNKNOWN_TYPE_PREFIX_ERR</code></a> are defined.
+            </p>
+          </dd>
+        </dl>
+        <p>
+          The <dfn id="dom-domerror-extensions-name"
+             title="dom-domerror-extensions-name"><code>name</code></dfn> attribute of a <a href=
+             "http://dom.spec.whatwg.org/#domerror"
+             class="externalDFN"><code>DOMError</code></a> object returned from this <abbr title=
+             "Application Programming Interface">API</abbr> <em class="ct"><em class="rfc2119"
+              title="MUST">MUST</em></em> return the name for the error, which will be one of the following:
+        </p>
+        <dl>
+          <dt>
+            <dfn id="dom-domerror-extensions-permission_denied"
+                title="dom-domerror-extensions-permission_denied"><code>PERMISSION_DENIED_ERR</code></dfn> (DOMString
+                value "PermissionDeniedError")
+          </dt>
+          <dd>
+            The user or user agent denied the page permission to access any services.
+          </dd>
+          <dt>
+            <dfn id="dom-domerror-extensions-unknown_type_prefix"
+                title="dom-domerror-extensions-unknown_type_prefix"><code>UNKNOWN_TYPE_PREFIX_ERR</code></dfn>
+                (DOMString value "UnknownTypePrefixError")
+          </dt>
+          <dd>
+            No <a href="#dfn-valid-service-type"
+                class="internalDFN">valid service type</a> tokens were provided in the method invocation.
+          </dd>
+        </dl>
+      </section>
+    </section>
+    <section id="obtaining-networked-services">
+      <h2 aria-level="1"
+          role="heading"
+          id="h2_obtaining-networked-services">
+        <span class="secno">6.</span> Obtaining networked services
+      </h2>
+      <p>
+        The <a href="#networkservices"><code>NetworkServices</code></a> interface represents a collection of zero or
+        more <a href="#dfn-indexed-properties"
+           class="internalDFN">indexed properties</a> that are each a <a href="#dfn-user-authorized"
+           class="internalDFN">user-authorized</a> <a href="#networkservice"><code>NetworkService</code></a> object.
+      </p>
+      <p>
+        A <a href="#networkservices"><code>NetworkServices</code></a> object is the <a href=
+        "http://dom.spec.whatwg.org/#concept-promise-result"
+           class="externalDFN">promise result</a> from a call to <a href=
+           "#dom-navigator-getnetworkservices"><code>getNetworkServices()</code></a>.
+      </p>
+      <pre class="widl">
+[NoInterfaceObject]
+interface <dfn id="networkservices">NetworkServices</dfn> {
+  readonly attribute unsigned long    <a href="#dom-networkservices-length">length</a>;
+  getter <a href="#networkservice">NetworkService</a> (unsigned long index);
+  <a href="#networkservice">NetworkService</a>? <a href=
+"#dom-networkservices-getservicebyid">getServiceById</a>(DOMString id);
+
+  readonly attribute unsigned long    <a href="#dom-networkservices-servicesavailable">servicesAvailable</a>;
+
+  // event handler attributes
+           attribute <a href="http://www.whatwg.org/specs/web-apps/current-work/multipage/webappapis.html#eventhandler"
+     class="externalDFN">EventHandler</a>     <a href="#dom-networkservices-onservicefound">onservicefound</a>;
+           attribute <a href="http://www.whatwg.org/specs/web-apps/current-work/multipage/webappapis.html#eventhandler"
+     class="externalDFN">EventHandler</a>     <a href="#dom-networkservices-onservicelost">onservicelost</a>;
+
+};
+
+<a href="#networkservices">NetworkServices</a> implements <a href=
+"http://dvcs.w3.org/hg/domcore/raw-file/tip/Overview.html#interface-eventtarget"
+     class="externalDFN">EventTarget</a>;
+</pre>
+      <section id="attributes">
+        <h3 aria-level="2"
+            role="heading"
+            id="h3_attributes">
+          <span class="secno">6.1</span> Attributes
+        </h3>
+        <dl class="domintro">
+          <dt>
+            <code title="dom-networkservices-length"><a href="#dom-networkservices-length">length</a></code>
+          </dt>
+          <dd>
+            <p>
+              Returns the current number of <a href="#dfn-indexed-properties"
+                 class="internalDFN">indexed properties</a> in the current object's collection.
+            </p>
+          </dd>
+          <dt>
+            <code title="dom-networkservices-servicesavailable"><a href=
+            "#dom-networkservices-servicesavailable">servicesAvailable</a></code>
+          </dt>
+          <dd>
+            <p>
+              Returns the current number of items matching one of the app-requested <a href="#dfn-valid-service-type"
+                 class="internalDFN">valid service type</a> tokens in the <a href=
+                 "#dfn-list-of-available-service-records"
+                 class="internalDFN">list of available service records</a>.
+            </p>
+          </dd>
+        </dl>
+        <div>
+          <p>
+            The <dfn id="dom-networkservices-length"><code>length</code></dfn> attribute <em class="rfc2119"
+               title="MUST">MUST</em> return the number of <a href="#networkservice"><code>NetworkService</code></a>
+               objects represented by the collection.
+          </p>
+          <p>
+            The <dfn id="dom-networkservices-servicesavailable"><code>servicesAvailable</code></dfn> attribute
+            <em class="rfc2119"
+               title="MUST">MUST</em> return the number of services in the <a href=
+               "#dfn-list-of-available-service-records"
+               class="internalDFN">list of available service records</a> whose <code>type</code> attribute matches any
+               of the <a href="#dfn-valid-service-type"
+               class="internalDFN">valid service type</a> tokens that were initially used to create the current <a href=
+               "#networkservices"><code>NetworkServices</code></a> object.
+          </p>
+        </div>
+      </section>
+      <section id="methods-1">
+        <h3 aria-level="2"
+            role="heading"
+            id="h3_methods-1">
+          <span class="secno">6.2</span> Methods
+        </h3>
+        <dl class="domintro">
+          <dt>
+            <code title="networkservices-getter"><a href="#networkservices">services</a></code> [ <var title=
+            "">index</var> ]
+          </dt>
+          <dd>
+            <p>
+              Returns the specified <a href="#networkservice"><code>NetworkService</code></a> object.
+            </p>
+          </dd>
+          <dt>
+            <code title="networkservices-getter"><a href="#networkservices">services</a></code> . <code title=
+            "dom-networkservices-getservicebyid"><a href=
+            "#dom-networkservices-getservicebyid">getServiceById</a></code> ( <var title="">id</var> )
+          </dt>
+          <dd>
+            <p>
+              Returns the <a href="#networkservice"><code>NetworkService</code></a> object with the given identifier,
+              or null if no service has that identifier.
+            </p>
+          </dd>
+        </dl>
+        <p>
+          A <a href="#networkservices"><code>NetworkServices</code></a> object represents the current collection of
+          zero or more <a href="#networkservice"><code>NetworkService</code></a> objects - its <a href=
+          "#dfn-indexed-properties"
+             class="internalDFN">indexed properties</a>. The <a href="#dfn-indexed-properties"
+             class="internalDFN">indexed properties</a> of a <a href=
+             "#networkservices"><code>NetworkServices</code></a> object are <span>immutable</span> meaning that <a href=
+             "#dfn-indexed-properties"
+             class="internalDFN">indexed properties</a> cannot be added and <a href="#dfn-indexed-properties"
+             class="internalDFN">indexed properties</a> cannot be removed for the lifetime of a <a href=
+             "#networkservices"><code>NetworkServices</code></a> object.
+        </p>
+        <p>
+          The <a href=
+          "http://www.whatwg.org/specs/web-apps/current-work/multipage/infrastructure.html#supported-property-indices"
+             class="externalDFN">supported property indices</a> of <a href=
+             "#networkservices"><code>NetworkServices</code></a> objects at any instant are the numbers from zero to
+             the number of the <a href="#networkservice"><code>NetworkService</code></a> objects in the collection
+             minus one.
+        </p>
+        <div class="note">
+          <div class="note-title"
+               aria-level="3"
+               role="heading"
+               id="h_note_2">
+            <span>Note</span>
+          </div>
+          <p class="">
+            Each service in a <a href="#networkservices"><code>NetworkServices</code></a> object thus has an index; the
+            first has the index 0, and each subsequent service is numbered one higher than the previous one.
+          </p>
+        </div>
+        <p>
+          To <a href=
+          "http://www.whatwg.org/specs/web-apps/current-work/multipage/infrastructure.html#determine-the-value-of-an-indexed-property"
+             class="externalDFN">determine the value of an indexed property</a> for a given index <var>index</var> in a
+             <a href="#networkservices"><code>NetworkServices</code></a> object the user agent <em class="rfc2119"
+             title="MUST">MUST</em> return the <a href="#networkservice"><code>NetworkService</code></a> object that
+             represents the <var>index</var>th item in the collection.
+        </p>
+        <p>
+          The <dfn id="dom-networkservices-getservicebyid"><code>getServiceById(id)</code></dfn> method <em class=
+          "ct"><em class="rfc2119"
+              title="MUST">MUST</em></em> return the first <a href="#networkservice"><code>NetworkService</code></a>
+              object in the collection whose <a href="#dom-networkservice-id"><code>id</code></a> attribute is equal to
+              the value of the <var>id</var> argument provided. When no <a href=
+              "#networkservice"><code>NetworkService</code></a> objects match the given argument, the method <em class=
+              "rfc2119"
+             title="MUST">MUST</em> return null.
+        </p>
+      </section>
+      <section id="events">
+        <h3 aria-level="2"
+            role="heading"
+            id="h3_events">
+          <span class="secno">6.3</span> Events
+        </h3>
+        <p>
+          The following are the event handlers (and their corresponding event handler event types) that <em class=
+          "ct"><em class="rfc2119"
+              title="MUST">MUST</em></em> be supported, as IDL attributes, by all objects implementing the <a href=
+              "#networkservices"><code>NetworkServices</code></a> interface:
+        </p>
+        <table border="1">
+          <thead>
+            <tr>
+              <th>
+                <span title="event handlers">Event handler</span>
+              </th>
+              <th>
+                <span>Event handler event type</span>
+              </th>
+            </tr>
+          </thead>
+          <tbody>
+            <tr>
+              <td>
+                <dfn id="dom-networkservices-onservicefound"
+                    title="dom-NetworkServices-onservicefound"><code>onservicefound</code></dfn>
+              </td>
+              <td>
+                <a href="#event-servicefound"><code>servicefound</code></a>
+              </td>
+            </tr>
+            <tr>
+              <td>
+                <dfn id="dom-networkservices-onservicelost"
+                    title="dom-NetworkServices-onservicelost"><code>onservicelost</code></dfn>
+              </td>
+              <td>
+                <a href="#event-servicelost"><code>servicelost</code></a>
+              </td>
+            </tr>
+          </tbody>
+        </table>
+      </section>
+    </section>
+    <section id="communicating-with-a-networked-service">
+      <h2 aria-level="1"
+          role="heading"
+          id="h2_communicating-with-a-networked-service">
+        <span class="secno">7.</span> Communicating with a networked service
+      </h2>
+      <p>
+        The <a href="#networkservice"><code>NetworkService</code></a> interface is used to provide a set of connection
+        information for an <abbr title="Hypertext Transfer Protocol">HTTP</abbr> service endpoint and if available,
+        service events, running on a networked device.
+      </p>
+      <pre class="widl">
+[NoInterfaceObject]
+interface <dfn id="networkservice">NetworkService</dfn> {
+  readonly attribute DOMString        <a href="#dom-networkservice-id">id</a>;
+  readonly attribute DOMString        <a href="#dom-networkservice-name">name</a>;
+  readonly attribute DOMString        <a href="#dom-networkservice-type">type</a>;
+  readonly attribute DOMString        <a href="#dom-networkservice-url">url</a>;
+  readonly attribute DOMString        <a href="#dom-networkservice-config">config</a>;
+
+  readonly attribute boolean          <a href="#dom-networkservice-online">online</a>;
+
+  // event handler attributes
+           attribute <a href="http://www.whatwg.org/specs/web-apps/current-work/multipage/webappapis.html#eventhandler"
+     class="externalDFN">EventHandler</a>     <a href="#dom-networkservice-onavailable">onavailable</a>;
+           attribute <a href="http://www.whatwg.org/specs/web-apps/current-work/multipage/webappapis.html#eventhandler"
+     class="externalDFN">EventHandler</a>     <a href="#dom-networkservice-onunavailable">onunavailable</a>;
+
+           attribute <a href="http://www.whatwg.org/specs/web-apps/current-work/multipage/webappapis.html#eventhandler"
+     class="externalDFN">EventHandler</a>     <a href="#dom-networkservice-onnotify">onnotify</a>;
+};
+
+<a href="#networkservice">NetworkService</a> implements <a href=
+"http://dvcs.w3.org/hg/domcore/raw-file/tip/Overview.html#interface-eventtarget"
+     class="externalDFN">EventTarget</a>;
+</pre>
+      <section id="attributes-1">
+        <h3 aria-level="2"
+            role="heading"
+            id="h3_attributes-1">
+          <span class="secno">7.1</span> Attributes
+        </h3>
+        <dl class="domintro">
+          <dt>
+            <var title="">service</var> . <code title="dom-networkservice-id"><a href=
+            "#dom-networkservice-id">id</a></code>
+          </dt>
+          <dd>
+            <p>
+              A unique identifier for the given user-selected service instance.
+            </p>
+          </dd>
+          <dt>
+            <var title="">service</var> . <code title="dom-networkservice-name"><a href=
+            "#dom-networkservice-name">name</a></code>
+          </dt>
+          <dd>
+            <p>
+              The name of the user-selected service.
+            </p>
+          </dd>
+          <dt>
+            <var title="">service</var> . <code title="dom-networkservice-type"><a href=
+            "#dom-networkservice-type">type</a></code>
+          </dt>
+          <dd>
+            <p>
+              The <a href="#dfn-valid-service-type"
+                 class="internalDFN">valid service type</a> token value of the user-selected service.
+            </p>
+          </dd>
+          <dt>
+            <var title="">service</var> . <code title="dom-networkservice-url"><a href=
+            "#dom-networkservice-url">url</a></code>
+          </dt>
+          <dd>
+            <p>
+              The control URL endpoint (including any required port information) of the user-selected control service.
+            </p>
+          </dd>
+          <dt>
+            <var title="">service</var> . <code title="dom-networkservice-config"><a href=
+            "#dom-networkservice-config">config</a></code>
+          </dt>
+          <dd>
+            <p>
+              The configuration information associated with the service depending on the requested service type.
+            </p>
+          </dd>
+        </dl>
+        <p>
+          The <dfn id="dom-networkservice-id"><code>id</code></dfn> attribute is a unique identifier for the service.
+          The same service provided at different times or on different objects <em class="rfc2119"
+             title="MUST">MUST</em> have the same <a href="#dom-networkservice-id"><code>id</code></a> value.
+        </p>
+        <p>
+          The <dfn id="dom-networkservice-name"><code>name</code></dfn> attribute represents a human-readable title for
+          the service.
+        </p>
+        <p>
+          The <dfn id="dom-networkservice-type"><code>type</code></dfn> attribute reflects the value of the <a href=
+          "#dfn-valid-service-type"
+             class="internalDFN">valid service type</a> of the service.
+        </p>
+        <p>
+          The <dfn id="dom-networkservice-url"><code>url</code></dfn> attribute is an <a href=
+          "http://url.spec.whatwg.org/#concept-absolute-url"
+             class="externalDFN">absolute URL</a> pointing to the root <abbr title=
+             "Hypertext Transfer Protocol">HTTP</abbr> endpoint for the service. Web pages can subsequently use this
+             value for implicit cross-document messaging via various existing mechanisms (e.g. Web Sockets, Server-Sent
+             Events, Web Messaging, XMLHttpRequest).
+        </p>
+        <p>
+          The <dfn id="dom-networkservice-config"><code>config</code></dfn> attribute provides the raw configuration
+          information extracted from the given network service.
+        </p>
+      </section>
+      <section id="states">
+        <h3 aria-level="2"
+            role="heading"
+            id="h3_states">
+          <span class="secno">7.2</span> States
+        </h3>
+        <dl class="domintro">
+          <dt>
+            <var title="">service</var> . <code title="dom-networkservice-online"><a href=
+            "#dom-networkservice-online">online</a></code>
+          </dt>
+          <dd>
+            <p>
+              Returns <code>true</code> if the service is reporting that it is accessible on the local network or
+              <code>false</code> if the service is no longer accessible (temporarily or permanently) on the local
+              network.
+            </p>
+          </dd>
+        </dl>
+        <p>
+          The <dfn id="dom-networkservice-online"><code>online</code></dfn> attribute indicates whether the service is
+          either <var>online</var>, and therefore accessible on the local network, in which case this attribute will
+          return <code>true</code> or, <var>offline</var>, and therefore not accessible on the local network, either
+          temporarily or permanently, in which case this attribute will return <code>false</code>. This attribute
+          <em class="rfc2119"
+             title="MUST">MUST</em> default to <code>true</code>.
+        </p>
+      </section>
+      <section id="events-1">
+        <h3 aria-level="2"
+            role="heading"
+            id="h3_events-1">
+          <span class="secno">7.3</span> Events
+        </h3>
+        <p>
+          The following are the event handlers (and their corresponding event handler event types) that <em class=
+          "ct"><em class="rfc2119"
+              title="MUST">MUST</em></em> be supported, as IDL attributes, by all objects implementing the <a href=
+              "#networkservice"><code>NetworkService</code></a> interface:
+        </p>
+        <table border="1">
+          <thead>
+            <tr>
+              <th>
+                <span title="event handlers">Event handler</span>
+              </th>
+              <th>
+                <span>Event handler event type</span>
+              </th>
+            </tr>
+          </thead>
+          <tbody>
+            <tr>
+              <td>
+                <dfn id="dom-networkservice-onnotify"
+                    title="dom-NetworkService-onnotify"><code>onnotify</code></dfn>
+              </td>
+              <td>
+                <a href="#event-notify"><code>notify</code></a>
+              </td>
+            </tr>
+            <tr>
+              <td>
+                <dfn id="dom-networkservice-onavailable"
+                    title="dom-NetworkService-onavailable"><code>onavailable</code></dfn>
+              </td>
+              <td>
+                <a href="#event-available"><code>available</code></a>
+              </td>
+            </tr>
+            <tr>
+              <td>
+                <dfn id="dom-networkservice-onunavailable"
+                    title="dom-NetworkService-onunavailable"><code>onunavailable</code></dfn>
+              </td>
+              <td>
+                <a href="#event-unavailable"><code>unavailable</code></a>
+              </td>
+            </tr>
+          </tbody>
+        </table>
+      </section>
+    </section>
+    <section id="service-discovery">
+      <h2 aria-level="1"
+          role="heading"
+          id="h2_service-discovery">
+        <span class="secno">8.</span> Service Discovery
+      </h2>
+      <p>
+        A <a href="#dfn-user-agent"
+           class="internalDFN">user agent</a> conforming to this specification <em class="rfc2119"
+           title="MAY">MAY</em> implement <abbr title="Simple Service Discovery Protocol">SSDP</abbr> [<cite><a class=
+           "bibref"
+           href="#bib-UPNP-DEVICEARCH11">UPNP-DEVICEARCH11</a></cite>], Zeroconf [<cite><a class="bibref"
+           href="#bib-DNS-SD">DNS-SD</a></cite>] + [<cite><a class="bibref"
+           href="#bib-MDNS">MDNS</a></cite>] and/or <abbr title="Discovery and Launch Protocol">DIAL</abbr> [<a href=
+           "https://sites.google.com/a/dial-multiscreen.org/dial/dial-protocol-specification"><abbr title=
+           "Discovery and Launch Protocol">DIAL</abbr></a>] <dfn id="dfn-service-discovery-mechanisms">service
+           discovery mechanisms</dfn> - the requirements detailed in this section of the specification - to enable Web
+           pages to request and connect with <abbr title="Hypertext Transfer Protocol">HTTP</abbr> services running on
+           networked devices, discovered via any of these mechanisms, through this <abbr title=
+           "Application Programming Interface">API</abbr>. When a <a href="#dfn-user-agent"
+           class="internalDFN">user agent</a> implements any of these <a href="#dfn-service-discovery-mechanisms"
+           class="internalDFN">service discovery mechanisms</a>, then it <em class="rfc2119"
+           title="MUST">MUST</em> conform to the corresponding algorithms provided in this section of the
+           specification.
+      </p>
+      <p>
+        This section presents how the results of these <a href="#dfn-service-discovery-mechanisms"
+           class="internalDFN">service discovery mechanisms</a> will be matched to requested service types, how the
+           user agent stores available and active services and how their properties are applied to any resulting
+           <a href="#networkservice"><code>NetworkService</code></a> objects.
+      </p>
+      <p>
+        It is expected that user agents will perform these <a href="#dfn-service-discovery-mechanisms"
+           class="internalDFN">service discovery mechanisms</a> asynchronously and periodically update the <a href=
+           "#dfn-list-of-available-service-records"
+           class="internalDFN">list of available service records</a> as required. The timing of any <a href=
+           "#dfn-service-discovery-mechanisms"
+           class="internalDFN">service discovery mechanisms</a> is an implementation detail left to the discretion of
+           the implementer (e.g. by continuously monitoring the network as a background process or on invocation of
+           this <abbr title="Application Programming Interface">API</abbr> from a Web page).
+      </p>
+      <p>
+        The <dfn id="dfn-list-of-available-service-records">list of available service records</dfn> is a single dynamic
+        internal lookup table within user agents that is used to track all the services that have been discovered and
+        are available in the current network at the current time. At any point during the running of any of the
+        <a href="#dfn-service-discovery-mechanisms"
+           class="internalDFN">service discovery mechanisms</a> then existing entries within this table can be updated,
+           entries can be added and entries can be removed as the status of networked services changes according to the
+           rules defined in this specification.
+      </p>
+      <p>
+        The <dfn id="dfn-list-of-active-service-managers">list of active service managers</dfn> is an internal list
+        within user agents that is used to track all <a href="#networkservices"><code>NetworkServices</code></a>
+        objects currently being shared with any web pages at the current time within the user agent. Each <a href=
+        "#networkservices"><code>NetworkServices</code></a> object in the <a href=
+        "#dfn-list-of-active-service-managers"
+           class="internalDFN">list of active service managers</a> represents a collection of zero or more <a href=
+           "#networkservice"><code>NetworkService</code></a> objects - known as its <dfn id=
+           "dfn-indexed-properties">indexed properties</dfn>. <a href="#networkservice"><code>NetworkService</code></a>
+           objects are attached as the <a href="#dfn-indexed-properties"
+           class="internalDFN">indexed properties</a> of a <a href="#networkservices"><code>NetworkServices</code></a>
+           object as part of the <a href="#dom-navigator-getnetworkservices"><code>getNetworkServices()</code></a>
+           algorithm.
+      </p>
+      <p>
+        The rule for <dfn id="dfn-adding-an-available-service">adding an available service</dfn> is the process of
+        adding a <a href="#dfn-new-service"
+           class="internalDFN">new service</a> or updating an <a href="#dfn-existing-service"
+           class="internalDFN">existing service</a> that is generally available on the user's current network in the
+           <a href="#dfn-list-of-available-service-records"
+           class="internalDFN">list of available service records</a>. This rule takes one argument, <var>network
+           service record</var>, and consists of running the following steps:
+      </p>
+      <ol class="rule">
+        <li>For each <var>existing service record</var> in the current <a href="#dfn-list-of-available-service-records"
+              class="internalDFN">list of available service records</a>, run the following sub-steps:
+          <ol class="rule">
+            <li>If the <var>existing service record</var>'s <code>id</code> property does not equal <var>network
+            service record</var>'s <code>id</code> property then abort any remaining sub-steps and continue at the next
+            available <var>existing service record</var>.
+            </li>
+            <li>Replace the value of <var>existing service record</var> in the current <a href=
+            "#dfn-list-of-available-service-records"
+                  class="internalDFN">list of available service records</a> with the value of <var>network service
+                  record</var>, aborting any remaining steps in this algorithm and return.
+            </li>
+          </ol>
+        </li>
+        <li>Add <var>network service record</var> to the <a href="#dfn-list-of-available-service-records"
+              class="internalDFN">list of available service records</a> as a new item.
+        </li>
+        <li>For each <var>service manager</var> in the <a href="#dfn-list-of-active-service-managers"
+              class="internalDFN">list of active service managers</a> run the following steps:
+          <ol class="rule">
+            <li>For each <var>active service</var> in <var>service manager</var> run the following steps:
+              <ol class="rule">
+                <li>If the <var>network service record</var>'s <code>id</code> property equals the <var>active
+                service</var>'s <code>id</code> attribute and <var>active service</var>'s <code>online</code> attribute
+                is currently set to <code>false</code> then set <var>active service</var>'s <a href=
+                "#dom-networkservice-online"><code>online</code></a> attribute to <code>true</code> and then <a href=
+                "http://www.whatwg.org/specs/web-apps/current-work/complete/webappapis.html#queue-a-task"
+                      class="externalDFN">queue a task</a> to dispatch a newly created event with the name <a href=
+                      "#event-available"><code>available</code></a> that uses the <a href=
+                      "http://dvcs.w3.org/hg/domcore/raw-file/tip/Overview.html#event"
+                      class="externalDFN"><code>Event</code></a> interface, which does not bubble, is not cancellable,
+                      and has no default action, at the current <var>active service</var> object.
+                </li>
+              </ol>
+            </li>
+            <li>Let <var>'service type in current service manager' flag</var> be <code>false</code>.
+            </li>
+            <li>For each <var>requested control type</var> of the <var>requested control types</var> in <var>service
+            manager</var> run the following steps:
+              <ol class="rule">
+                <li>If <var>network service record</var>'s <code>type</code> property does not equal <var>requested
+                control type</var> then abort any remaining sub-steps and continue at the next available <var>requested
+                control type</var>.
+                </li>
+                <li>Set the <var>'service type in current service manager' flag</var> to <code>true</code>, abort any
+                remaining sub-steps and continue.
+                </li>
+              </ol>
+            </li>
+            <li>If the <var>'service type in current service manager' flag</var> is set to <code>true</code> then
+            increment <var>service manager</var>'s <a href=
+            "#dom-networkservices-servicesavailable"><code>servicesAvailable</code></a> attribute by <code>1</code> and
+            then <a href="http://www.whatwg.org/specs/web-apps/current-work/complete/webappapis.html#queue-a-task"
+                  class="externalDFN">queue a task</a> to dispatch a newly created event with the name <a href=
+                  "#event-servicefound"><code>servicefound</code></a> that uses the <a href=
+                  "http://dvcs.w3.org/hg/domcore/raw-file/tip/Overview.html#event"
+                  class="externalDFN"><code>Event</code></a> interface, which does not bubble, is not cancellable, and
+                  has no default action, at the current <var>service manager</var> object.
+            </li>
+          </ol>
+        </li>
+      </ol>
+      <p>
+        The rule for <dfn id="dfn-removing-an-available-service">removing an available service</dfn> is the general
+        process of removing an <a href="#dfn-existing-service"
+           class="internalDFN">existing service</a> from the <a href="#dfn-list-of-available-service-records"
+           class="internalDFN">list of available service records</a> that has left the user's current network or has
+           otherwise expired. This rule takes one argument, <var>service identifier</var>, and consists of running the
+           following steps:
+      </p>
+      <ol class="rule">
+        <li>For each <var>existing service record</var> in the current <a href="#dfn-list-of-available-service-records"
+              class="internalDFN">list of available service records</a>, run the following sub-steps:
+          <ol class="rule">
+            <li>If the <var>existing service record</var>'s <code>id</code> property does not match <var>service
+            identifier</var> then skip any remaining sub-steps for the current <var>existing service record</var> and
+            continue at the next available <var>existing service record</var>.
+            </li>
+            <li>Let <var>'service type in use' flag</var> be <code>false</code>.
+            </li>
+            <li>For each <var>service manager</var> in the <a href="#dfn-list-of-active-service-managers"
+                  class="internalDFN">list of active service managers</a> run the following steps:
+              <ol class="rule">
+                <li>Let <var>'service type in current service manager' flag</var> be <code>false</code>.
+                </li>
+                <li>For each <var>active service</var> in <var>service manager</var> run the following steps:
+                  <ol class="rule">
+                    <li>If <var>existing service record</var>'s <code>id</code> property equals the <var>active
+                    service</var>'s <code>id</code> attribute and <var>active service</var>'s <a href=
+                    "#dom-networkservice-online"><code>online</code></a> attribute is currently set to
+                    <code>true</code> then set <var>active service</var>'s <a href="#dom-networkservice-online"><code>
+                      online</code></a> attribute to <code>false</code> and then <a href=
+                      "http://www.whatwg.org/specs/web-apps/current-work/complete/webappapis.html#queue-a-task"
+                          class="externalDFN">queue a task</a> to dispatch a newly created event with the name <a href=
+                          "#event-unavailable"><code>unavailable</code></a> that uses the <a href=
+                          "http://dvcs.w3.org/hg/domcore/raw-file/tip/Overview.html#event"
+                          class="externalDFN"><code>Event</code></a> interface, which does not bubble, is not
+                          cancellable, and has no default action, at the current <var>active service</var>.
+                    </li>
+                  </ol>
+                </li>
+                <li>For each <var>requested control type</var> of the <var>requested control types</var> in
+                <var>service manager</var> run the following steps:
+                  <ol class="rule">
+                    <li>If <var>existing service record</var>'s <code>type</code> property does not equal
+                    <var>requested control type</var> then abort any remaining sub-steps and continue at the next
+                    available <var>requested control type</var>.
+                    </li>
+                    <li>Set the <var>'service type in current service manager' flag</var> to <code>true</code> and the
+                    <var>'service type in use' flag</var> to <code>true</code>, abort any remaining sub-steps and
+                    continue.
+                    </li>
+                  </ol>
+                </li>
+                <li>If the <var>'service type in current service manager' flag</var> is set to <code>true</code> then
+                decrement <var>service manager</var>'s <a href=
+                "#dom-networkservices-servicesavailable"><code>servicesAvailable</code></a> attribute by <code>1</code>
+                and then <a href=
+                "http://www.whatwg.org/specs/web-apps/current-work/complete/webappapis.html#queue-a-task"
+                      class="externalDFN">queue a task</a> to dispatch a newly created event with the name <a href=
+                      "#event-servicelost"><code>servicelost</code></a> that uses the <a href=
+                      "http://dvcs.w3.org/hg/domcore/raw-file/tip/Overview.html#event"
+                      class="externalDFN"><code>Event</code></a> interface, which does not bubble, is not cancellable,
+                      and has no default action, at the current <var>service manager</var> object.
+                </li>
+              </ol>
+            </li>
+            <li>If the <var>'service type in use' flag</var> is <code>false</code> and the <var>existing service
+            record</var>'s <code>type</code> property begins with the DOMString "<code>upnp:</code>" and <var>existing
+            service record</var>'s <code>eventsURL</code> property is set then run the rule to <a href=
+            "#dfn-terminate-an-existing-upnp-events-subscription"
+                  class="internalDFN">terminate an existing UPnP Events Subscription</a>, if one is currently active
+                  (as a result of having previously called <a href="#dfn-setup-a-upnp-events-subscription"
+                  class="internalDFN">setup a UPnP Events Subscription</a> against the current <var>existing service
+                  record</var>).
+            </li>
+            <li>Remove <var>existing service record</var> from the current <a href=
+            "#dfn-list-of-available-service-records"
+                  class="internalDFN">list of available service records</a>.
+            </li>
+          </ol>
+        </li>
+      </ol>
+      <p>
+        User agents <em class="rfc2119"
+           title="SHOULD">SHOULD</em> expire a service record from the <a href="#dfn-list-of-available-service-records"
+           class="internalDFN">list of available service records</a> when its <code>expiryTimestamp</code> attribute
+           exceeds the current UTC timestamp. When this condition is met the <a href="#dfn-user-agent"
+           class="internalDFN">user agent</a> <em class="rfc2119"
+           title="SHOULD">SHOULD</em> run the rule for <a href="#dfn-removing-an-available-service"
+           class="internalDFN">removing an available service</a>, passing in the expired service record's
+           <code>id</code> attribute as the only argument.
+      </p>
+      <section id="zeroconf-mdns-dns-sd">
+        <h3 aria-level="2"
+            role="heading"
+            id="h3_zeroconf-mdns-dns-sd">
+          <span class="secno">8.1</span> Zeroconf (<abbr title="Multicast DNS">mDNS</abbr> + <abbr title=
+          "Domain Name System">DNS</abbr>-<abbr title="Service Discovery">SD</abbr>)
+        </h3>
+        <p>
+          For each <abbr title="Domain Name System">DNS</abbr> response received from a user-agent-initiated Multicast
+          <abbr title="Domain Name System">DNS</abbr> Browse for <abbr title="DNS Pointer Record">PTR</abbr> records
+          with the name <code>_services._dns-sd._udp</code> on the resolved recommended automatic browsing domain
+          [<cite><a class="bibref"
+             href="#bib-MDNS">MDNS</a></cite>], the <a href="#dfn-user-agent"
+             class="internalDFN">user agent</a> <em class="rfc2119"
+             title="MUST">MUST</em> run the following steps:
+        </p>
+        <ol class="rule">
+          <li>Let <var>service <abbr title="Multicast DNS">mDNS</abbr> responses</var> be an array of <abbr title=
+          "DNS Pointer Record">PTR</abbr> records received by issuing a Multicast <abbr title=
+          "Domain Name System">DNS</abbr> Browse for <abbr title="DNS Pointer Record">PTR</abbr> records with the name
+          of the current discovered service type.
+          </li>
+          <li>For each Object <var>service <abbr title="Multicast DNS">mDNS</abbr> response</var> in <var>service
+          <abbr title="Multicast DNS">mDNS</abbr> responses</var>, run the following steps:
+            <ol>
+              <li>Let <var>network service record</var> be an Object consisting of the following empty properties:
+              <code>id</code>, <code>name</code>, <code>type</code>, <code>url</code>, <code>config</code>,
+              <code>expiryTimestamp</code>.
+              </li>
+              <li>Set <var>network service record</var>'s <code>id</code> property to the value of the full
+                <abbr title="DNS Pointer Record">PTR</abbr> Service Instance Name [<cite><a class="bibref"
+                   href="#bib-MDNS">MDNS</a></cite>].
+              </li>
+              <li>Set <var>network service record</var>'s <code>name</code> property to the value of the <abbr title=
+              "DNS Pointer Record">PTR</abbr> Service Instance Name's <var>Instance</var> component [<cite><a class=
+              "bibref"
+                   href="#bib-MDNS">MDNS</a></cite>].
+              </li>
+              <li>Set <var>network service record</var>'s <code>type</code> property to the concatenation of the string
+              <code>zeroconf:</code> followed be the value of the <abbr title="DNS Pointer Record">PTR</abbr> Service
+              Instance Name's <var>Service</var> component [<cite><a class="bibref"
+                   href="#bib-MDNS">MDNS</a></cite>].
+              </li>
+              <li>Set <var>network service record</var>'s <code>url</code> property to the resolvable Service URL
+              obtained from performing an <abbr title="Domain Name System">DNS</abbr>-<abbr title=
+              "Service Discovery">SD</abbr> Lookup [<cite><a class="bibref"
+                   href="#bib-DNS-SD">DNS-SD</a></cite>] of the current service from the <abbr title=
+                   "DNS Pointer Record">PTR</abbr> record provided [<cite><a class="bibref"
+                   href="#bib-MDNS">MDNS</a></cite>].
+              </li>
+              <li>Set <var>network service record</var>'s <code>config</code> property to the string value of the
+              contents of the first <abbr title="Domain Name System">DNS</abbr>-<abbr title=
+              "Service Discovery">SD</abbr> TXT record associated with the <var>service <abbr title=
+              "Multicast DNS">mDNS</abbr> response</var> as defined in [<cite><a class="bibref"
+                   href="#bib-DNS-SD">DNS-SD</a></cite>].
+              </li>
+              <li>Set <var>network service record</var>'s <code>expiryTimestamp</code> property to the value of the
+              current date, in UTC timestamp format, plus a value of <code>120</code> seconds.
+              </li>
+              <li>Run the general rule for <a href="#dfn-adding-an-available-service"
+                    class="internalDFN">adding an available service</a>, passing in the current <var>network service
+                    record</var> as the only argument.
+              </li>
+            </ol>
+          </li>
+        </ol>
+      </section>
+      <section id="simple-service-discovery-protocol-ssdp">
+        <h3 aria-level="2"
+            role="heading"
+            id="h3_simple-service-discovery-protocol-ssdp">
+          <span class="secno">8.2</span> Simple Service Discovery Protocol (<abbr title=
+          "Simple Service Discovery Protocol">SSDP</abbr>)
+        </h3>
+        <p>
+          A user agent that implements UPnP service discovery <em class="rfc2119"
+             title="MUST">MUST</em> issue a <dfn id="dfn-search-request-for-upnp-root-devices">search request for UPnP
+             root devices</dfn> against the user's current local network according to the full normative text and
+             timing provided in 'Section 1.3.2: Search request with M-SEARCH' detailed in [<cite><a class="bibref"
+             href="#bib-UPNP-DEVICEARCH11">UPNP-DEVICEARCH11</a></cite>].
+        </p>
+        <p>
+          The user agent <em class="rfc2119"
+             title="MUST">MUST</em> issue all <a title="search request for UPnP root devices"
+             href="#dfn-search-request-for-upnp-root-devices"
+             class="internalDFN">search requests for UPnP root devices</a> with a <abbr title=
+             "Hypertext Transfer Protocol">HTTP</abbr> request line equal to <code>M-SEARCH * <abbr title=
+             "Hypertext Transfer Protocol">HTTP</abbr>/1.1</code>, with a HOST header equal to the reserved multicast
+             address and port of <code>239.255.255.250:1900</code> and a MAN header equal to
+             <code>ssdp:discover</code>. The <a href="#dfn-user-agent"
+             class="internalDFN">user agent</a> must also send an ST header with this <abbr title=
+             "Hypertext Transfer Protocol">HTTP</abbr> request equal to the String value of <code>ssdp:all</code> or
+             <code>upnp:rootdevice</code> or a single <a href="#dfn-valid-service-type"
+             class="internalDFN">valid service type</a> token beginning with the String value <code>upnp:</code>. If a
+             single <a href="#dfn-valid-service-type"
+             class="internalDFN">valid service type</a> token beginning with the String value <code>upnp:</code> is to
+             be used, the user agent <em class="rfc2119"
+             title="MUST">MUST</em> strip the leading String <code>upnp:</code> before using this value in this
+             <abbr title="Hypertext Transfer Protocol">HTTP</abbr> request. The user-agent <em class="rfc2119"
+             title="MUST">MUST</em> also send an MX header equal to a <dfn id=
+             "dfn-maximum-upnp-advertisement-response-wait-time">maximum UPnP advertisement response wait time</dfn>
+             value between <code>1</code> and <code>5</code> seconds with this <abbr title=
+             "Hypertext Transfer Protocol">HTTP</abbr> request.
+        </p>
+        <p>
+          The user agent <em class="rfc2119"
+             title="MUST">MUST</em> listen for any incoming responses to any <a href=
+             "#dfn-search-request-for-upnp-root-devices"
+             class="internalDFN">search request for UPnP root devices</a>.
+        </p>
+        <p>
+          For each <dfn id="dfn-http-response"><abbr title="Hypertext Transfer Protocol">HTTP</abbr> Response</dfn>
+          following an initial <a href="#dfn-search-request-for-upnp-root-devices"
+             class="internalDFN">search request for UPnP root devices</a> sent on a <a href=
+             "#dfn-standard-upnp-address-and-port"
+             class="internalDFN">standard UPnP address and port</a> the user agent <em class="rfc2119"
+             title="MUST">MUST</em> run the following steps:
+        </p>
+        <ol class="rule">
+          <li>If the <a href="#dfn-http-response"
+                class="internalDFN"><abbr title="Hypertext Transfer Protocol">HTTP</abbr> Response</a> is not a
+                <abbr title="Hypertext Transfer Protocol">HTTP</abbr> 200 OK response then this response is invalid and
+                the user agent <em class="rfc2119"
+                title="MUST">MUST</em> discard this response, abort any remaining steps and return. The user agent
+                <em class="rfc2119"
+                title="MAY">MAY</em> issue a new <a href="#dfn-search-request-for-upnp-root-devices"
+                class="internalDFN">search request for UPnP root devices</a> as a result of this error occurring.
+          </li>
+          <li>If the <a href="#dfn-maximum-upnp-advertisement-response-wait-time"
+                class="internalDFN">maximum UPnP advertisement response wait time</a> has been exceeded since the
+                initial <a href="#dfn-search-request-for-upnp-root-devices"
+                class="internalDFN">search request for UPnP root devices</a> was sent then the <a href=
+                "#dfn-http-response"
+                class="internalDFN"><abbr title="Hypertext Transfer Protocol">HTTP</abbr> Response</a> is invalid and
+                the user agent <em class="rfc2119"
+                title="MUST">MUST</em> discard this response, abort any remaining steps and return. The user agent
+                <em class="rfc2119"
+                title="MAY">MAY</em> stop listening for responses from the current <a href=
+                "#dfn-search-request-for-upnp-root-devices"
+                class="internalDFN">search request for UPnP root devices</a> as a result of this error occurring.
+                Equally, the user agent <em class="rfc2119"
+                title="MAY">MAY</em> issue a new <a href="#dfn-search-request-for-upnp-root-devices"
+                class="internalDFN">search request for UPnP root devices</a> as a result of this error occurring.
+          </li>
+          <li>Let <var>ssdp device</var> be an Object with a property for each <abbr title=
+          "Hypertext Transfer Protocol">HTTP</abbr> header received in the <a href="#dfn-http-response"
+                class="internalDFN"><abbr title="Hypertext Transfer Protocol">HTTP</abbr> Response</a>, with each key
+                being the name of a <abbr title="Hypertext Transfer Protocol">HTTP</abbr> response header and each
+                value being that <abbr title="Hypertext Transfer Protocol">HTTP</abbr> response header's value.
+          </li>
+          <li>If <var>ssdp device</var> does not contain at least one <var>CACHE-CONTROL</var> entry, at least one
+          <var>USN</var> entry, at least one <var>ST</var> entry and at least one <var>LOCATION</var> entry then the
+          <a href="#dfn-http-response"
+                class="internalDFN"><abbr title="Hypertext Transfer Protocol">HTTP</abbr> Response</a> is invalid and
+                the <a href="#dfn-user-agent"
+                class="internalDFN">user agent</a> <em class="rfc2119"
+                title="MUST">MUST</em> discard this response, abort any remaining steps and return.
+          </li>
+          <li>The user agent <em class="rfc2119"
+                title="MUST">MUST</em> run the rule for <a href="#dfn-obtaining-a-upnp-device-description-file"
+                class="internalDFN">obtaining a UPnP Device Description File</a> passing in the first occurrence of
+                <var>LOCATION</var> from <var>ssdp device</var> as the <var>device descriptor URL</var> argument and
+                the first occurrence of <var>USN</var> from <var>ssdp device</var> as the <var>device identifier</var>
+                argument and the first occurrence of <var>CACHE-CONTROL</var> from <var>ssdp device</var> (minus the
+                leading string of <code>max-age=</code>) as the <var>device expiry</var> argument.
+          </li>
+        </ol>
+        <p>
+          The user agent <em class="rfc2119"
+             title="MUST">MUST</em> listen for incoming requests on the <dfn id=
+             "dfn-standard-upnp-address-and-port">standard UPnP address and port</dfn> on all current local network
+             interface addresses with the port <code>1900</code>.
+        </p>
+        <p>
+          For each <dfn id="dfn-http-request"><abbr title="Hypertext Transfer Protocol">HTTP</abbr> Request</dfn>
+          received on a <a href="#dfn-standard-upnp-address-and-port"
+             class="internalDFN">standard UPnP address and port</a> the user agent <em class="rfc2119"
+             title="MUST">MUST</em> run the following steps:
+        </p>
+        <ol class="rule">
+          <li>If the <a href="#dfn-http-request"
+                class="internalDFN"><abbr title="Hypertext Transfer Protocol">HTTP</abbr> Request</a> is not a
+                <abbr title="Hypertext Transfer Protocol">HTTP</abbr> NOTIFY request then it is not a valid UPnP
+                Request and the user agent <em class="rfc2119"
+                title="MUST">MUST</em> discard this request, abort any remaining steps and return.
+          </li>
+          <li>Let <var>ssdp device</var> be an Object with a property for each <abbr title=
+          "Hypertext Transfer Protocol">HTTP</abbr> header received in the <a href="#dfn-http-request"
+                class="internalDFN"><abbr title="Hypertext Transfer Protocol">HTTP</abbr> Request</a>, with each key
+                being the name of a <abbr title="Hypertext Transfer Protocol">HTTP</abbr> header and each value being
+                that <abbr title="Hypertext Transfer Protocol">HTTP</abbr> header's value.
+          </li>
+          <li>If <var>ssdp device</var>'s <var>NTS</var> entry is equal to <code>ssdp:alive</code> and the <a href=
+          "#dfn-http-request"
+                class="internalDFN"><abbr title="Hypertext Transfer Protocol">HTTP</abbr> Request</a> does not contain
+                at least one <var>CACHE-CONTROL</var> entry, at least one <var>USN</var> entry, at least one
+                <var>NT</var> entry, at least one <var>NTS</var> entry and at least one <var>LOCATION</var> entry, then
+                the <a href="#dfn-user-agent"
+                class="internalDFN">user agent</a> <em class="rfc2119"
+                title="MUST">MUST</em> discard this request, abort any remaining steps and return.
+          </li>
+          <li>If <var>ssdp device</var>'s <var>NTS</var> entry is equal to <code>ssdp:alive</code> then the user agent
+          <em class="rfc2119"
+                title="MUST">MUST</em> run the rule for <a href="#dfn-obtaining-a-upnp-device-description-file"
+                class="internalDFN">obtaining a UPnP Device Description File</a> passing in the first occurrence of
+                <var>LOCATION</var> from <var>ssdp device</var> as the <var>device descriptor URL</var> argument and
+                the first occurrence of <var>USN</var> from <var>ssdp device</var> as the <var>device identifier</var>
+                argument and the first occurrence of <var>CACHE-CONTROL</var> from <var>ssdp device</var> (minus the
+                leading string of <code>max-age=</code>) as the <var>device expiry</var>.<br>
+            <br>
+            Otherwise, if <var>ssdp device</var>'s <var>NTS</var> entry is equal to <code>ssdp:byebye</code> then the
+            user agent <em class="rfc2119"
+                title="MUST">MUST</em> run the rule for <a href=
+                "#dfn-removing-all-services-from-a-registered-upnp-device"
+                class="internalDFN">removing all services from a registered UPnP Device</a> passing in the first
+                occurrence of <var>USN</var> from <var>ssdp device</var> as the <var>device identifier</var> argument.
+          </li>
+        </ol>
+        <p>
+          The rule for <dfn id="dfn-obtaining-a-upnp-device-description-file">obtaining a UPnP Device Description
+          File</dfn> is the process of obtaining the contents of a standard UPnP Device Description [<cite><a class=
+          "bibref"
+             href="#bib-UPNP-DEVICEARCH11">UPNP-DEVICEARCH11</a></cite>] from a URL-based resource. This rule takes
+             three arguments - <var>device descriptor URL</var>, <var>device identifier</var> and <var>device
+             expiry</var> - and when called the user agent <em class="rfc2119"
+             title="MUST">MUST</em> run the following steps:
+        </p>
+        <ol class="rule">
+          <li>Let <var>device descriptor file</var> contain the contents of the file located at the URL provided in
+          <var>device descriptor URL</var> obtained according to the rules defined in 'Section 2.11: Retrieving a
+          description using <abbr title="Hypertext Transfer Protocol">HTTP</abbr>' in [<cite><a class="bibref"
+               href="#bib-UPNP-DEVICEARCH11">UPNP-DEVICEARCH11</a></cite>].
+          </li>
+          <li>If the value provided in <var>device descriptor URL</var> cannot be resolved as a reachable URL on the
+          current network or the <var>device descriptor file</var> remains empty then it is invalid and the <a href=
+          "#dfn-user-agent"
+                class="internalDFN">user agent</a> <em class="rfc2119"
+                title="MUST">MUST</em> abort any remaining steps and return.
+          </li>
+          <li>Run the rule for <a href="#dfn-processing-a-upnp-device-description-file"
+                class="internalDFN">processing a UPnP Device Description File</a>, passing in the current <var>device
+                descriptor file</var>, <var>device identifier</var> and <var>device expiry</var> arguments.
+          </li>
+        </ol>
+        <p>
+          The rule for <dfn id="dfn-processing-a-upnp-device-description-file">processing a UPnP Device Description
+          File</dfn> is the process of parsing the contents of a standard UPnP Device Description [<cite><a class=
+          "bibref"
+             href="#bib-UPNP-DEVICEARCH11">UPNP-DEVICEARCH11</a></cite>] and registering the UPnP services contained
+             therein within the <a href="#dfn-list-of-available-service-records"
+             class="internalDFN">list of available service records</a>.
+        </p>
+        <p>
+          The rule for <a href="#dfn-processing-a-upnp-device-description-file"
+             class="internalDFN">processing a UPnP Device Description File</a> takes three arguments - <var>device
+             descriptor file</var>, <var>device identifier</var> and <var>device expiry</var> - and when called the
+             user agent <em class="rfc2119"
+             title="MUST">MUST</em> run the following steps:
+        </p>
+        <ol class="rule">
+          <li>Let <var>advertised services</var> be a list of all advertised services obtained from the <var>device
+          descriptor file</var> containing the value of the first occurrence of the <code>&lt;serviceList&gt;</code>
+          element as it is defined in 'Section 2.3: Device Description' in [<cite><a class="bibref"
+               href="#bib-UPNP-DEVICEARCH11">UPNP-DEVICEARCH11</a></cite>].
+          </li>
+          <li>For each <code>&lt;service&gt;</code> element - known as an <var>advertised service</var> - in
+          <var>advertised services</var> run the following steps:
+            <ol class="rule">
+              <li>Let <var>network service record</var> be a new Object consisting of the following empty properties:
+              <code>id</code>, <code>deviceId</code>, <code>name</code>, <code>type</code>, <code>url</code>,
+              <code>eventsUrl</code>, <code>config</code>, <code>expiryTimestamp</code>.
+              </li>
+              <li>Set <var>network service record</var>'s <code>id</code> property to the concatenated string value of
+              the first occurrence of the <code>&lt;UDN&gt;</code> element in the <var>device descriptor file</var>
+              with the <var>advertised service</var>'s <code>&lt;serviceId&gt;</code> sub-element.
+              </li>
+              <li>Set <var>network service record</var>'s <code>deviceId</code> property to the value of <var>device
+              identifier</var>.
+              </li>
+              <li>Set <var>network service record</var>'s <code>name</code> property to the string value of the first
+              occurrence of the <var>advertised service</var>'s <code>&lt;serviceId&gt;</code> sub-element.
+              </li>
+              <li>Set <var>network service record</var>'s <code>type</code> property to the concatenation of the string
+              <code>upnp:</code> followed by the string value of the first occurrence of the <var>advertised
+              service</var>'s <code>&lt;serviceType&gt;</code> sub-element.
+              </li>
+              <li>Set <var>network service record</var>'s <code>url</code> property to the string value of the first
+              occurrence of the <var>advertised service</var>'s <code>&lt;controlURL&gt;</code> sub-element.
+              </li>
+              <li>Set <var>network service record</var>'s <code>config</code> property to the string value of the
+              contents of the first occurrence of the <code>&lt;device&gt;</code> element in the <var>device descriptor
+              file</var>.
+              </li>
+              <li>If <var>advertised service</var>'s <code>&lt;eventSubURL&gt;</code> sub-element is not empty, then
+              set <var>network service record</var>'s <code>eventsUrl</code> property to the string value of the first
+              occurrence of the <var>advertised service</var>'s <code>&lt;eventSubURL&gt;</code> sub-element.
+              Otherwise, do not set <var>network service record</var>'s <code>eventsUrl</code> property.
+              </li>
+              <li>Set <var>network service record</var>'s <code>expiryTimestamp</code> property to the value of the
+              current date, in UTC timestamp format, plus the value of <var>device expiry</var>.
+              </li>
+              <li>Run the general rule for <a href="#dfn-adding-an-available-service"
+                    class="internalDFN">adding an available service</a>, passing in the current <var>network service
+                    record</var> as the only argument.
+              </li>
+            </ol>
+          </li>
+          <li>If <var>device descriptor file</var> contains a <code>&lt;deviceList&gt;</code> element then for each
+          <code>&lt;device&gt;</code> element within <code>&lt;deviceList&gt;</code> - herein known as an <var>embedded
+          device descriptor file</var> - the user agent <em class="rfc2119"
+                title="MUST">MUST</em> run the rule for <a href="#dfn-processing-a-upnp-device-description-file"
+                class="internalDFN">processing a UPnP Device Description File</a>, passing in the current <var>embedded
+                device descriptor file</var> as the <var>device descriptor file</var> argument, along with the current
+                <var>device identifier</var> and <var>device expiry</var> arguments.
+          </li>
+        </ol>
+        <p>
+          The rule for <dfn id="dfn-removing-all-services-from-a-registered-upnp-device">removing all services from a
+          registered UPnP Device</dfn> is the process of removing all services associated with a device from the
+          <a href="#dfn-list-of-available-service-records"
+             class="internalDFN">list of available service records</a> that has left the user's current network or has
+             otherwise timed out or expired. This rule takes one argument, <var>device identifier</var>, and consists
+             of running the following steps:
+        </p>
+        <ol class="rule">
+          <li>For each <var>existing service record</var> in the current <a href=
+          "#dfn-list-of-available-service-records"
+                class="internalDFN">list of available service records</a>, run the following sub-steps:
+            <ol class="rule">
+              <li>If the <var>existing service record</var>'s <code>deviceId</code> property does not match <var>device
+              identifier</var> then skip any remaining sub-steps for the current <var>existing service record</var> and
+              continue at the next available <var>existing service record</var>.
+              </li>
+              <li>Run the general rule for <a href="#dfn-removing-an-available-service"
+                    class="internalDFN">removing an available service</a> passing in <var>existing service
+                    record</var>'s <code>id</code> property as the only argument.
+              </li>
+            </ol>
+          </li>
+        </ol>
+        <p>
+          When the <a href="#dfn-user-agent"
+             class="internalDFN">user agent</a> is to <dfn id="dfn-setup-a-upnp-events-subscription">setup a UPnP
+             Events Subscription</dfn>, it is to run the following steps with the current <var>network service
+             record</var> object as defined in 'Section 4.1.2: SUBSCRIBE with NT and CALLBACK' in [<cite><a class=
+             "bibref"
+             href="#bib-UPNP-DEVICEARCH11">UPNP-DEVICEARCH11</a></cite>]:
+        </p>
+        <ol class="rule">
+          <li>If <var>network service record</var>'s <code>eventsUrl</code> property is empty then the <a href=
+          "#dfn-user-agent"
+                class="internalDFN">user agent</a> <em class="rfc2119"
+                title="MUST">MUST</em> abort these steps.
+          </li>
+          <li>Let <var>callback URL</var> be the value of creating a new <a href=
+          "#dfn-user-agent-generated-callback-url"
+                class="internalDFN">user-agent generated callback url</a>.
+          </li>
+          <li>Send a <abbr title="Hypertext Transfer Protocol">HTTP</abbr> SUBSCRIBE request with a <em>NT</em> header
+          with a string value of <code>upnp:event</code>, a <em>TIMEOUT</em> header with a user-agent defined timeout
+          value (in the form <code>Second-XX</code> where <code>XX</code> is the user-agent defined timeout value in
+          seconds) and a <em>CALLBACK</em> header with a string value of <var>callback URL</var> towards the
+          <var>network service record</var>'s <code>eventsUrl</code> property.
+          </li>
+          <li>If a non-200 OK response is received from the <abbr title="Hypertext Transfer Protocol">HTTP</abbr>
+          SUBSCRIBE request then the <a href="#dfn-user-agent"
+                class="internalDFN">user agent</a> <em class="rfc2119"
+                title="MUST">MUST</em> abort these steps.
+          </li>
+          <li>On receiving a valid 200 OK response, run the following steps:
+            <ol class="rule">
+              <li>Let <var>callback ID</var> equal the string value of the first included <em>SID</em> header, if it
+              exists.
+              </li>
+              <li>Let <var>timeout date</var> equal the sum of the current UTC date value plus the integer value of the
+              first included <em>TIMEOUT</em> header (minus the leading string of <code>Second-</code>), if it exists.
+              </li>
+              <li>Run the following steps asynchronously and continue to the step labeled <em>listen</em> below.
+              </li>
+              <li>
+                <em>Refresh Subscription</em>: Run the following steps at a set interval (X) within the <a href=
+                "#dfn-user-agent"
+                    class="internalDFN">user agent</a>:
+                <ol class="rule">
+                  <li>Let <var>current date</var> equal the current UTC date.
+                  </li>
+                  <li>If <var>current date</var> is less than the <var>timeout date</var> then continue to the step
+                  labeled <em>refresh subscription</em> above.
+                  </li>
+                  <li>Send a <abbr title="Hypertext Transfer Protocol">HTTP</abbr> SUBSCRIBE request with a
+                  <em>SID</em> header with the string value of <var>callback ID</var> and a user-agent defined
+                  <em>TIMEOUT</em> header (in the form <code>Second-XX</code> where <code>XX</code> is the user-agent
+                  defined timeout value in seconds) towards the <var>network service record</var>'s
+                  <code>eventsUrl</code> property.
+                  </li>
+                  <li>On receiving a valid 200 OK, update <var>callback ID</var> with the string value of the first
+                  included <em>SID</em> header and set <var>timeout date</var> to the sum of the current UTC date value
+                  plus the integer value of the first included <em>TIMEOUT</em> header (minus the leading string of
+                  <code>Second-</code>), if it exists. If the current date is greater than or equal to <var>timeout
+                  date</var> then the <a href="#dfn-user-agent"
+                        class="internalDFN">user agent</a> <em class="rfc2119"
+                        title="SHOULD">SHOULD</em> continue from the step labeled <em>refresh subscription</em> above.
+                        For all non 200 OK responses the <a href="#dfn-user-agent"
+                        class="internalDFN">user agent</a> <em class="rfc2119"
+                        title="SHOULD">SHOULD</em> continue from the step labeled <em>refresh subscription</em> above.
+                  </li>
+                </ol>
+              </li>
+              <li>
+                <em>Listen</em>: For each <abbr title="Hypertext Transfer Protocol">HTTP</abbr> NOTIFY request received
+                at the <var>callback URL</var> the <a href="#dfn-user-agent"
+                    class="internalDFN">user agent</a> is to run the following steps:
+                <ol class="rule">
+                  <li>Let <var>content clone</var> be the result of obtaining the message body of the <abbr title=
+                  "Hypertext Transfer Protocol">HTTP</abbr> NOTIFY request. If <var>content clone</var> is empty, then
+                  the <a href="#dfn-user-agent"
+                        class="internalDFN">user agent</a> <em class="rfc2119"
+                        title="MUST">MUST</em> abort these steps.
+                  </li>
+                  <li>Let <var>notification event</var> be a new simple event that uses the <a href=
+                  "http://dvcs.w3.org/hg/domcore/raw-file/tip/Overview.html#event"
+                        class="externalDFN"><code>Event</code></a> interface with the name <a href=
+                        "#event-notify"><code>notify</code></a>, which does not bubble, is not cancellable, and has no
+                        default action.
+                  </li>
+                  <li>Let the <code>data</code> attribute of <var>notification event</var> have the DOMString value of
+                  <var>content clone</var>.
+                  </li>
+                  <li>
+                    <a href="http://www.whatwg.org/specs/web-apps/current-work/complete/webappapis.html#queue-a-task"
+                        class="externalDFN">Queue a task</a> to dispatch <var>notification event</var> at the current
+                        <a href="#networkservice"
+                        class="internalDFN"><code>NetworkService</code></a> object.
+                  </li>
+                  <li>Return a <abbr title="Hypertext Transfer Protocol">HTTP</abbr> 200 OK response to the sender of
+                  the <abbr title="Hypertext Transfer Protocol">HTTP</abbr> NOTIFY request.
+                  </li>
+                </ol>
+              </li>
+            </ol>
+          </li>
+        </ol>
+        <p>
+          A <a href="#dfn-user-agent"
+             class="internalDFN">user agent</a> can <dfn id=
+             "dfn-terminate-an-existing-upnp-events-subscription">terminate an existing UPnP Events Subscription</dfn>
+             at any time for a <var>network service record</var> by sending an <abbr title=
+             "Hypertext Transfer Protocol">HTTP</abbr> UNSUBSCRIBE request - as defined in 'Section 4.1.4: Cancelling a
+             subscription with UNSUBSCRIBE' in [<cite><a class="bibref"
+             href="#bib-UPNP-DEVICEARCH11">UPNP-DEVICEARCH11</a></cite>] - with a HOST header set to that <var>active
+             service</var>'s <code>eventsUrl</code> property and a SID header set to the <var>callback ID</var>
+             obtained when the initial <a href="#dfn-setup-a-upnp-events-subscription"
+             class="internalDFN">setup a UPnP Events Subscription</a> action occurred.
+        </p>
+      </section>
+      <section id="discovery-and-launch-protocol-dial">
+        <h3 aria-level="2"
+            role="heading"
+            id="h3_discovery-and-launch-protocol-dial">
+          <span class="secno">8.3</span> Discovery and Launch Protocol (<abbr title=
+          "Discovery and Launch Protocol">DIAL</abbr>)
+        </h3>
+        <p>
+          A user agent that implements <abbr title="Discovery and Launch Protocol">DIAL</abbr> service discovery
+          <em class="rfc2119"
+             title="MUST">MUST</em> issue a <dfn id="dfn-search-request-for-dial-enabled-devices">search request for
+             <abbr title="Discovery and Launch Protocol">DIAL</abbr>-enabled devices</dfn> against the user's current
+             local network according to the full normative text and timing provided in 'Section 1.3.2: Search request
+             with M-SEARCH' detailed in [<cite><a class="bibref"
+             href="#bib-UPNP-DEVICEARCH11">UPNP-DEVICEARCH11</a></cite>].
+        </p>
+        <p>
+          Let <var>dial version</var> be the version number specified in the <a href="#dfn-valid-service-type"
+             class="internalDFN">valid service type</a> token. Let <var>dial search target</var> be the concatentation
+             of the <code>urn:dial-multiscreen-org:service:dial:</code> string constant with the <var>dial
+             version</var> (currently, <var>dial version</var> can only be <code>1</code>)
+        </p>
+        <p>
+          The user agent <em class="rfc2119"
+             title="MUST">MUST</em> issue all <a title="search request for DIAL-enabled devices"
+             href="#dfn-search-request-for-dial-enabled-devices"
+             class="internalDFN">search requests for <abbr title="Discovery and Launch Protocol">DIAL</abbr>-enabled
+             devices</a> with a <abbr title="Hypertext Transfer Protocol">HTTP</abbr> request line equal to
+             <code>M-SEARCH * <abbr title="Hypertext Transfer Protocol">HTTP</abbr>/1.1</code>, with a HOST header
+             equal to the reserved multicast address and port of <code>239.255.255.250:1900</code>, a MAN header equal
+             to <code>ssdp:discover</code>, an ST header equal to <var>dial search target</var> and a user-agent
+             defined MX header equal to a <dfn id="dfn-maximum-dial-advertisement-response-wait-time">maximum
+             <abbr title="Discovery and Launch Protocol">DIAL</abbr> advertisement response wait time</dfn> value
+             between <code>1</code> and <code>5</code> seconds.
+        </p>
+        <p>
+          The user agent <em class="rfc2119"
+             title="MUST">MUST</em> listen for any incoming responses to a <a href=
+             "#dfn-search-request-for-dial-enabled-devices"
+             class="internalDFN">search request for <abbr title="Discovery and Launch Protocol">DIAL</abbr>-enabled
+             devices</a>.
+        </p>
+        <p>
+          For each <abbr title="Hypertext Transfer Protocol">HTTP</abbr> Response following an initial <a href=
+          "#dfn-search-request-for-dial-enabled-devices"
+             class="internalDFN">search request for <abbr title="Discovery and Launch Protocol">DIAL</abbr>-enabled
+             devices</a> sent on a <a href="#dfn-standard-upnp-address-and-port"
+             class="internalDFN">standard UPnP address and port</a> the user agent <em class="rfc2119"
+             title="MUST">MUST</em> run the following steps:
+        </p>
+        <ol class="rule">
+          <li>If the <abbr title="Hypertext Transfer Protocol">HTTP</abbr> Response is not a <abbr title=
+          "Hypertext Transfer Protocol">HTTP</abbr> 200 OK response then this response is invalid and the user agent
+          <em class="rfc2119"
+                title="MUST">MUST</em> discard this response, abort any remaining steps and return. The user agent
+                <em class="rfc2119"
+                title="MAY">MAY</em> issue a new <a href="#dfn-search-request-for-dial-enabled-devices"
+                class="internalDFN">search request for <abbr title="Discovery and Launch Protocol">DIAL</abbr>-enabled
+                devices</a> as a result of this error occurring.
+          </li>
+          <li>If the <a href="#dfn-maximum-dial-advertisement-response-wait-time"
+                class="internalDFN">maximum <abbr title="Discovery and Launch Protocol">DIAL</abbr> advertisement
+                response wait time</a> has been exceeded since the initial <a href=
+                "#dfn-search-request-for-dial-enabled-devices"
+                class="internalDFN">search request for <abbr title="Discovery and Launch Protocol">DIAL</abbr>-enabled
+                devices</a> was sent then the <a href="#dfn-http-response"
+                class="internalDFN"><abbr title="Hypertext Transfer Protocol">HTTP</abbr> Response</a> is invalid and
+                the user agent <em class="rfc2119"
+                title="MUST">MUST</em> discard this response, abort any remaining steps and return. The user agent
+                <em class="rfc2119"
+                title="MAY">MAY</em> stop listening for responses from the current <a href=
+                "#dfn-search-request-for-dial-enabled-devices"
+                class="internalDFN">search request for <abbr title="Discovery and Launch Protocol">DIAL</abbr>-enabled
+                devices</a> as a result of this error occurring. Equally, the user agent <em class="rfc2119"
+                title="MAY">MAY</em> issue a new <a href="#dfn-search-request-for-dial-enabled-devices"
+                class="internalDFN">search request for <abbr title="Discovery and Launch Protocol">DIAL</abbr>-enabled
+                devices</a> as a result of this error occurring.
+          </li>
+          <li>Let <var>dial device</var> be an Object with a property for each <abbr title=
+          "Hypertext Transfer Protocol">HTTP</abbr> header received in the <a href="#dfn-http-response"
+                class="internalDFN"><abbr title="Hypertext Transfer Protocol">HTTP</abbr> Response</a>, with each key
+                being the name of a <abbr title="Hypertext Transfer Protocol">HTTP</abbr> response header and each
+                value being that <abbr title="Hypertext Transfer Protocol">HTTP</abbr> response header's value.
+          </li>
+          <li>If <var>dial device</var> does not contain at least one <var>CACHE-CONTROL</var> entry, at least one
+          <var>USN</var> entry, at least one <var>ST</var> entry and at least one <var>LOCATION</var> entry or the
+          value of its <var>ST</var> entry is not <var>dial search target</var>, then the <a href="#dfn-http-response"
+                class="internalDFN"><abbr title="Hypertext Transfer Protocol">HTTP</abbr> Response</a> is invalid and
+                the <a href="#dfn-user-agent"
+                class="internalDFN">user agent</a> <em class="rfc2119"
+                title="MUST">MUST</em> discard this response, abort any remaining steps and return.
+          </li>
+          <li>The user agent <em class="rfc2119"
+                title="MUST">MUST</em> run the rule for <a href="#dfn-obtaining-a-upnp-device-description-file"
+                class="internalDFN">obtaining a UPnP Device Description File</a> passing in the first occurrence of
+                <var>LOCATION</var> from <var>dial device</var> as the <var>device descriptor URL</var> argument and
+                the first occurrence of <var>USN</var> from <var>dial device</var> as the <var>device identifier</var>
+                argument and the first occurrence of <var>CACHE-CONTROL</var> from <var>dial device</var> (minus the
+                leading string of <code>max-age=</code>) as the <var>device expiry</var> argument.
+          </li>
+        </ol>
+        <p>
+          The rule for <dfn id="dfn-obtaining-a-dial-device-description-file">obtaining a <abbr title=
+          "Discovery and Launch Protocol">DIAL</abbr> Device Description File</dfn> is the process of obtaining the
+          contents of a standard UPnP Device Description [<cite><a class="bibref"
+             href="#bib-UPNP-DEVICEARCH11">UPNP-DEVICEARCH11</a></cite>] from a URL-based resource. This rule takes
+             three arguments - <var>device descriptor URL</var>, <var>device identifier</var> and <var>device
+             expiry</var> - and when called the user agent <em class="rfc2119"
+             title="MUST">MUST</em> run the following steps:
+        </p>
+        <ol class="rule">
+          <li>Let <var>device descriptor file</var> contain the contents of the file located at the URL provided in
+          <var>device descriptor URL</var> obtained according to the rules defined in 'Section 2.11: Retrieving a
+          description using <abbr title="Hypertext Transfer Protocol">HTTP</abbr>' in [<cite><a class="bibref"
+               href="#bib-UPNP-DEVICEARCH11">UPNP-DEVICEARCH11</a></cite>].
+          </li>
+          <li>Let <var>application url</var> be the value of the first occurrence of the <code>Application-URL</code>
+          response header field obtained according to the rules defined in 'Section 5.4: Device Description Response'
+          in [<a href="https://sites.google.com/a/dial-multiscreen.org/dial/dial-protocol-specification"><abbr title=
+          "Discovery and Launch Protocol">DIAL</abbr></a>]
+          </li>
+          <li>If the value provided in <var>device descriptor URL</var> cannot be resolved as a reachable URL on the
+          current network or the <var>device descriptor file</var> remains empty or <var>application url</var> is
+          undefined then it is invalid and the <a href="#dfn-user-agent"
+                class="internalDFN">user agent</a> <em class="rfc2119"
+                title="MUST">MUST</em> abort any remaining steps and return.
+          </li>
+          <li>Run the following steps to add the newly discovered <abbr title=
+          "Discovery and Launch Protocol">DIAL</abbr> service:
+            <ol class="rule">
+              <li>Let <var>network service record</var> be a new Object consisting of the following empty properties:
+              <code>id</code>, <code>deviceId</code>, <code>name</code>, <code>type</code>, <code>url</code>,
+              <code>expiryTimestamp</code>.
+              </li>
+              <li>Set <var>network service record</var>'s <code>id</code> property to the first occurrence of the
+              <code>&lt;UDN&gt;</code> element in the <var>descriptor file</var> prefixed with the <code>dial:</code>
+              string constant
+              </li>
+              <li>Set <var>network service record</var>'s <code>deviceId</code> property to the value of <var>device
+              identifier</var>.
+              </li>
+              <li>Set <var>network service record</var>'s <code>name</code> property to the string value of the first
+              occurrence of the <code>&lt;friendlyName&gt;</code> element in the <var>descriptor file</var>.
+              </li>
+              <li>Set <var>network service record</var>'s <code>type</code> property to <var>dial search target</var>.
+              </li>
+              <li>Set <var>network service record</var>'s <code>url</code> property to the string value of the
+              <var>application url</var>.
+              </li>
+              <li>Set <var>network service record</var>'s <code>expiryTimestamp</code> property to the value of the
+              current date, in UTC timestamp format, plus the value of <var>device expiry</var>.
+              </li>
+              <li>Run the general rule for <a href="#dfn-adding-an-available-service"
+                    class="internalDFN">adding an available service</a>, passing in the current <var>network service
+                    record</var> as the only argument.
+              </li>
+            </ol>
+          </li>
+        </ol>
+      </section>
+      <section id="network-topology-monitoring">
+        <h3 aria-level="2"
+            role="heading"
+            id="h3_network-topology-monitoring">
+          <span class="secno">8.4</span> Network Topology Monitoring
+        </h3>
+        <div>
+          <p>
+            When the <a href="#dfn-user-agent"
+               class="internalDFN">user agent</a> detects that the user has dropped from a connected network then, for
+               each <var>existing service record</var> in the <a href="#dfn-list-of-available-service-records"
+               class="internalDFN">list of available service records</a> discovered via that network connection, the
+               <a href="#dfn-user-agent"
+               class="internalDFN">user agent</a> <em class="rfc2119"
+               title="MUST">MUST</em> run the general rule for <a href="#dfn-removing-an-available-service"
+               class="internalDFN">removing an available service</a> passing in each <var>existing service
+               record</var>'s <code>id</code> property as the only argument for each call.
+          </p>
+          <p>
+            When the <a href="#dfn-user-agent"
+               class="internalDFN">user agent</a> detects that the user has connected to a new network or reconnected
+               to an existing network, then it <em class="rfc2119"
+               title="SHOULD">SHOULD</em> restart its discovery mechanisms as defined in the <a href=
+               "#service-discovery">Service Discovery</a> section of this specification, maintaining the existing
+               <a href="#dfn-list-of-active-service-managers"
+               class="internalDFN">list of active service managers</a> currently in use.
+          </p>
+        </div>
+      </section>
+    </section>
+    <section id="events-summary">
+      <h2 aria-level="1"
+          role="heading"
+          id="h2_events-summary">
+        <span class="secno">9.</span> Events Summary
+      </h2>
+      <p>
+        The following events are dispatched on the <a href="#networkservices"><code>NetworkServices</code></a> and/or
+        <a href="#networkservice"><code>NetworkService</code></a> objects:
+      </p>
+      <table border="1">
+        <thead>
+          <tr>
+            <th>
+              <span>Event name</span>
+            </th>
+            <th>
+              <span>Interface</span>
+            </th>
+            <th>
+              <span>Dispatched when...</span>
+            </th>
+          </tr>
+        </thead>
+        <tbody>
+          <tr>
+            <td>
+              <dfn id="event-servicefound"><code>servicefound</code></dfn>
+            </td>
+            <td>
+              <a href="http://dvcs.w3.org/hg/domcore/raw-file/tip/Overview.html#event"
+                  class="externalDFN"><code>Event</code></a>
+            </td>
+            <td>
+              When a <a href="#dfn-new-service"
+                  class="internalDFN">new service</a> that matches one of the <a title="valid service type"
+                  href="#dfn-valid-service-type"
+                  class="internalDFN">requested type tokens</a> is found in the current network.
+            </td>
+          </tr>
+          <tr>
+            <td>
+              <dfn id="event-servicelost"><code>servicelost</code></dfn>
+            </td>
+            <td>
+              <a href="http://dvcs.w3.org/hg/domcore/raw-file/tip/Overview.html#event"
+                  class="externalDFN"><code>Event</code></a>
+            </td>
+            <td>
+              When an <a href="#dfn-existing-service"
+                  class="internalDFN">existing service</a> that matches one of the <a title="valid service type"
+                  href="#dfn-valid-service-type"
+                  class="internalDFN">requested type tokens</a> gracefully leaves or expires from the current network.
+            </td>
+          </tr>
+          <tr>
+            <td>
+              <dfn id="event-available"><code>available</code></dfn>
+            </td>
+            <td>
+              <a href="http://dvcs.w3.org/hg/domcore/raw-file/tip/Overview.html#event"
+                  class="externalDFN"><code>Event</code></a>
+            </td>
+            <td>
+              When a <a href="#dfn-current-service"
+                  class="internalDFN">current service</a> renews its service registration within the current network.
+            </td>
+          </tr>
+          <tr>
+            <td>
+              <dfn id="event-unavailable"><code>unavailable</code></dfn>
+            </td>
+            <td>
+              <a href="http://dvcs.w3.org/hg/domcore/raw-file/tip/Overview.html#event"
+                  class="externalDFN"><code>Event</code></a>
+            </td>
+            <td>
+              When a <a href="#dfn-current-service"
+                  class="internalDFN">current service</a> gracefully leaves or otherwise expires from the current
+                  network.
+            </td>
+          </tr>
+          <tr>
+            <td>
+              <dfn id="event-notify"><code>notify</code></dfn>
+            </td>
+            <td>
+              <a href="http://dvcs.w3.org/hg/domcore/raw-file/tip/Overview.html#event"
+                  class="externalDFN"><code>Event</code></a>
+            </td>
+            <td>
+              When a valid UPnP Events Subscription Message is received on a <a href=
+              "#dfn-user-agent-generated-callback-url"
+                  class="internalDFN">user-agent generated callback url</a> for a <a href="#dfn-current-service"
+                  class="internalDFN">current service</a>. This event never fires for Zeroconf-based services.
+            </td>
+          </tr>
+        </tbody>
+      </table>
+    </section>
+    <section id="garbage-collection">
+      <h2 aria-level="1"
+          role="heading"
+          id="h2_garbage-collection">
+        <span class="secno">10.</span> Garbage collection
+      </h2>
+      <p>
+        There is an <dfn id="dfn-implied-strong-reference">implied strong reference</dfn> from any IDL attribute in
+        this <abbr title="Application Programming Interface">API</abbr> that returns a pre-existing object to that
+        object.
+      </p>
+      <div class="note">
+        <div class="note-title"
+             aria-level="2"
+             role="heading"
+             id="h_note_3">
+          <span>Note</span>
+        </div>
+        <p class="">
+          For example, if a <a href="#networkservices"
+             class="internalDFN"><code>NetworkServices</code></a> object has one or more <a href=
+             "#dfn-indexed-properties"
+             class="internalDFN">indexed properties</a> attached to it then there is a strong reference from that
+             <a href="#networkservices"
+             class="internalDFN"><code>NetworkServices</code></a> object toward each of its <a href=
+             "#dfn-indexed-properties"
+             class="internalDFN">indexed properties</a>.
+        </p>
+      </div>
+      <p>
+        If a <a href="#dfn-user-agent"
+           class="internalDFN">user agent</a> is to <dfn id="dfn-make-disappear">make disappear</dfn> a <a href=
+           "#networkservices"
+           class="internalDFN"><code>NetworkServices</code></a> object (this happens when a <a href=
+           "http://www.whatwg.org/specs/web-apps/current-work/multipage/dom.html#document"
+           class="externalDFN"><code>Document</code></a> object goes away), the <a href="#dfn-user-agent"
+           class="internalDFN">user agent</a> <em class="rfc2119"
+           title="MUST">MUST</em> remove this object from the <a href="#dfn-list-of-active-service-managers"
+           class="internalDFN">list of active service managers</a>.
+      </p>
+    </section>
+    <section id="use-cases-and-requirements">
+      <h2 aria-level="1"
+          role="heading"
+          id="h2_use-cases-and-requirements">
+        <span class="secno">11.</span> Use Cases and Requirements
+      </h2>
+      <p>
+        This section covers what the requirements are for this <abbr title=
+        "Application Programming Interface">API</abbr>, as well as illustrates some use cases.
+      </p>
+      <ul class="rule">
+        <li>Once a user has given permission, user agents should provide the ability for Web pages to communicate
+        directly with a Local-networked Service.
+          <ul class="rule">
+            <li>Example: A web-based TV remote control. A Web page wants to control the current user's TV, changing the
+            programming shown or increasing/decreasing/muting the volume of the Local-networked Device. The Web page
+            requests a service type that is known to be implemented by television sets to which it has the application
+            logic to communicate. Local devices providing the request service types are discovered and presented to the
+            user for authorization. The user selects one or more of the discovered television sets to be accessible to
+            the current Web page and then clicks 'Share'. The Web page can now communicate directly with the
+            user-authorized Local-networked services.
+            </li>
+          </ul>
+        </li>
+        <li>Web pages should be able to communicate with Local-networked Services using the messaging channel supported
+        by those Devices.
+          <ul class="rule">
+            <li>Example: A Web page advertises that it is capable of controlling multiple Home Media Servers. The user
+            can select their Home Media Server type from a drop-down list, at which point the Web page sends a request
+            to the user agent to connect with the associated service type of the Home Media Server. The Media Server
+            selected implements a Web Socket channel for bi-directional service communication and so the Web page opens
+            a web socket to the requested Media Server and can communicate as required via that appropriate channel.
+            </li>
+          </ul>
+        </li>
+        <li>Web pages should be able to communicate with Local-networked Services using the messaging format supported
+        by those Devices.
+          <ul class="rule">
+            <li>Example: A Web page advertises that it is capable of interacting with and controlling multiple types of
+            Home Media Server. The user can select their Home Media Server type from a drop-down list or known Media
+            Servers, at which point the Web page sends a request to the user agent to connect with the associated
+            service type (and, optionally, the associated event type) of the Home Media Server. The communication
+            protocols supported by Home Media Servers typically vary between UPnP, JSON-RPC, Protocol Buffers or other
+            messaging formats depending on the Home Media Server requested. The Web page is able to communicate with
+            the user-selected Home Media Server in the messaging format supported by that Device, which, in this
+            example is a simple key/value pair text format.
+            </li>
+          </ul>
+        </li>
+        <li>Web pages should not be able to communicate with Local-networked Services that have not been authorized by
+        the user thereby maintaining the user's privacy.
+          <ul class="rule">
+            <li>Example: A Web page requests access to one type of Local-networked service. The user authorizes access
+            to that particular service. Other services running on that same device, and on other devices within the
+            network, should not be accessible to the current Web page.
+            </li>
+          </ul>
+        </li>
+        <li>A user should be able to share one or more Local-networked Services based on a particular service type
+        request from a Web page.
+          <ul class="rule">
+            <li>Example: A Web page is capable of interacting with a specific profile of Local-networked Service. As
+            such, it makes a request to the user agent to access those services, of which multiple matches are found.
+            The user is capable of selecting one or more of the discovered services to share with the Web page. The Web
+            page can then implement a drag-and-drop interface for the user to drag specific actions on to one or more
+            of the authorized Local-networked Services.
+            </li>
+          </ul>
+        </li>
+        <li>User agents should provide an <abbr title="Application Programming Interface">API</abbr> exposed to script
+        that exposes the features above. The user is notified by UI anytime interaction with Local-networked Services
+        is requested, giving the user full ability to cancel or abort the transaction. The user selects the
+        Local-networked Services to be connected to the current Web page, and can cancel these at any time. No
+        invocations to these APIs occur silently without user intervention.
+        </li>
+      </ul>
+    </section>
+    <section class="informative appendix"
+             id="examples">
+      <h2 aria-level="1"
+          role="heading"
+          id="h2_examples">
+        <span class="secno">A.</span> Examples
+      </h2>
+      <p>
+        <em>This section is non-normative.</em>
+      </p>
+      <div class="example">
+        <p>
+          This sample code exposes a button. When clicked, this button is disabled and the user is prompted to offer a
+          network service. The user may also select multiple network services. When the user has authorized a network
+          service to be connected to the web page then the web page issues a simple command to get a list of all the
+          albums stored on the connected media player service.
+        </p>
+        <p>
+          The button is re-enabled only when the connected network service disconnects for whatever reason (the service
+          becomes unavailable on the network, the user disconnects from their current network or the user revokes
+          access to the service from the current web page). At this point the user can re-click the button to select a
+          new network service to connect to the web page and the above steps are repeated.
+        </p>
+        <p>
+          The provided service type identifier and service interaction used in this example is based on the
+          well-defined service type and messaging format supported by the <a href="http://xbmc.org/about/">XBMC Media
+          Server</a>.
+        </p>
+        <hr>
+        <pre class="highlight prettyprint prettyprinted"
+             style="">
+<span class="tag">&lt;input</span><span class="pln"> </span><span class="atn">type</span><span class=
+"pun">=</span><span class="atv">"button"</span><span class="pln"> </span><span class="atn">value</span><span class=
+"pun">=</span><span class="atv">"Start"</span><span class="pln"> </span><span class="atn">onclick</span><span class=
+"pun">=</span><span class="atv">"</span><span class="pln">start</span><span class="pun">()</span><span class=
+"atv">"</span><span class="pln"> </span><span class="atn">id</span><span class="pun">=</span><span class=
+"atv">"startBtn"</span><span class="tag">/&gt;</span><span class="pln">
+</span><span class="tag">&lt;div</span><span class="pln"> </span><span class="atn">id</span><span class=
+"pun">=</span><span class="atv">"debugconsole"</span><span class="tag">&gt;&lt;/div&gt;</span><span class="pln">
+
+</span><span class="tag">&lt;script&gt;</span><span class="pln">
+ </span><span class="kwd">var</span><span class="pln"> startBtn </span><span class="pun">=</span><span class=
+"pln"> document</span><span class="pun">.</span><span class="pln">getElementById</span><span class=
+"pun">(</span><span class="str">'startBtn'</span><span class="pun">),</span><span class="pln">
+     debug </span><span class="pun">=</span><span class="pln"> document</span><span class="pun">.</span><span class=
+"pln">getElementById</span><span class="pun">(</span><span class="str">'debugconsole'</span><span class=
+"pun">);</span><span class="pln">
+
+ </span><span class="kwd">function</span><span class="pln"> start</span><span class="pun">()</span><span class=
+"pln"> </span><span class="pun">{</span><span class="pln">
+   </span><span class="kwd">if</span><span class="pun">(</span><span class="pln">navigator</span><span class=
+"pun">.</span><span class="pln">getNetworkServices</span><span class="pun">)</span><span class=
+"pln"> </span><span class="pun">{</span><span class="pln">
+      navigator</span><span class="pun">.</span><span class="pln">getNetworkServices</span><span class=
+"pun">(</span><span class="str">'zeroconf:_xbmc-jsonrpc._tcp'</span><span class="pun">).</span><span class=
+"pln">then</span><span class="pun">(</span><span class="pln">gotXBMCService</span><span class=
+"pun">).</span><span class="kwd">catch</span><span class="pun">(</span><span class="pln">error</span><span class=
+"pun">);</span><span class="pln">
+      startBtn</span><span class="pun">.</span><span class="pln">disabled </span><span class="pun">=</span><span class=
+"pln"> </span><span class="kwd">true</span><span class="pun">;</span><span class="pln">
+   </span><span class="pun">}</span><span class="pln"> </span><span class="kwd">else</span><span class=
+"pln"> </span><span class="pun">{</span><span class="pln">
+      debug</span><span class="pun">.</span><span class="pln">innerHTML </span><span class="pun">+=</span><span class=
+"pln"> </span><span class="str">"&lt;br&gt;Service Discovery not supported!"</span><span class=
+"pun">;</span><span class="pln">
+   </span><span class="pun">}</span><span class="pln">
+ </span><span class="pun">}</span><span class="pln">
+
+ </span><span class="kwd">function</span><span class="pln"> gotXBMCService</span><span class="pun">(</span><span class=
+"pln">services</span><span class="pun">)</span><span class="pln"> </span><span class="pun">{</span><span class="pln">
+
+</span><span class="com">// Listen for service disconnect messages</span><span class="pln">
+
+   services</span><span class="pun">[</span><span class="lit">0</span><span class="pun">].</span><span class=
+"pln">addEventListener</span><span class="pun">(</span><span class="str">'unavailable'</span><span class=
+"pun">,</span><span class="pln"> </span><span class="kwd">function</span><span class="pln"> </span><span class=
+"pun">(</span><span class="pln"> e </span><span class="pun">)</span><span class="pln"> </span><span class=
+"pun">{</span><span class="pln">
+       debug</span><span class="pun">.</span><span class="pln">innerHTML </span><span class="pun">+=</span><span class=
+"pln"> </span><span class="str">"&lt;br&gt;"</span><span class="pln"> </span><span class="pun">+</span><span class=
+"pln"> services</span><span class="pun">[</span><span class="lit">0</span><span class="pun">].</span><span class=
+"pln">name </span><span class="pun">+</span><span class="pln"> </span><span class=
+"str">" disconnected."</span><span class="pun">;</span><span class="pln">
+       startBtn</span><span class="pun">.</span><span class="pln">disabled </span><span class=
+"pun">=</span><span class="pln"> </span><span class="kwd">false</span><span class="pun">;</span><span class="pln">
+   </span><span class="pun">},</span><span class="pln"> </span><span class="kwd">false</span><span class=
+"pun">);</span><span class="pln">
+
+</span><span class=
+"com">// Send a service message to get albums list (and process the service response)</span><span class="pln">
+
+   </span><span class="kwd">var</span><span class="pln"> svcXhr </span><span class="pun">=</span><span class=
+"pln"> </span><span class="kwd">new</span><span class="pln"> </span><span class="typ">XMLHttpRequest</span><span class=
+"pun">();</span><span class="pln">
+   svcXhr</span><span class="pun">.</span><span class="pln">open</span><span class="pun">(</span><span class=
+"str">"POST"</span><span class="pun">,</span><span class="pln"> services</span><span class="pun">[</span><span class=
+"lit">0</span><span class="pun">].</span><span class="pln">url </span><span class="pun">+</span><span class=
+"pln"> </span><span class="str">"/getAlbums"</span><span class="pun">);</span><span class="pln"> </span><span class=
+"com">// services[0].url and its sub-resources are</span><span class="pln">
+                                                        </span><span class=
+"com">// available for cross-site XHR use.</span><span class="pln">
+
+   svcXhr</span><span class="pun">.</span><span class="pln">setRequestHeader</span><span class=
+"pun">(</span><span class="str">'Content-Type'</span><span class="pun">,</span><span class="pln"> </span><span class=
+"str">'application/json-rpc'</span><span class="pun">);</span><span class="pln">
+
+   svcXhr</span><span class="pun">.</span><span class="pln">addEventListener</span><span class=
+"pun">(</span><span class="str">'readystatechange'</span><span class="pun">,</span><span class=
+"pln"> </span><span class="kwd">function</span><span class="pln"> </span><span class="pun">(</span><span class=
+"pln"> response </span><span class="pun">)</span><span class="pln"> </span><span class="pun">{</span><span class="pln">
+     </span><span class="kwd">if</span><span class="pun">(</span><span class="pln"> response</span><span class=
+"pun">.</span><span class="pln">readyState </span><span class="pun">!=</span><span class="pln"> </span><span class=
+"lit">4</span><span class="pln"> </span><span class="pun">||</span><span class="pln"> response</span><span class=
+"pun">.</span><span class="pln">status </span><span class="pun">!=</span><span class="pln"> </span><span class=
+"lit">200</span><span class="pln"> </span><span class="pun">)</span><span class="pln">
+        </span><span class="kwd">return</span><span class="pun">;</span><span class="pln">
+     debug</span><span class="pun">.</span><span class="pln">innerHTML </span><span class="pun">+=</span><span class=
+"pln"> </span><span class="str">"&lt;br&gt;"</span><span class="pln"> </span><span class="pun">+</span><span class=
+"pln"> services</span><span class="pun">[</span><span class="lit">0</span><span class="pun">].</span><span class=
+"pln">name </span><span class="pun">+</span><span class="pln"> </span><span class=
+"str">" response received: "</span><span class="pun">;</span><span class="pln">
+     debug</span><span class="pun">.</span><span class="pln">textContent </span><span class="pun">+=</span><span class=
+"pln"> JSON</span><span class="pun">.</span><span class="pln">parse</span><span class="pun">(</span><span class=
+"pln">response</span><span class="pun">.</span><span class="pln">responseText</span><span class=
+"pun">);</span><span class="pln">
+   </span><span class="pun">},</span><span class="pln"> </span><span class="kwd">false</span><span class=
+"pun">);</span><span class="pln">
+
+   </span><span class="kwd">var</span><span class="pln"> svcMsg </span><span class="pun">=</span><span class=
+"pln"> </span><span class="pun">[</span><span class="pln">
+     </span><span class="pun">{</span><span class="pln"> </span><span class="str">"jsonrpc"</span><span class=
+"pun">:</span><span class="pln"> </span><span class="str">"2.0"</span><span class="pun">,</span><span class=
+"pln"> </span><span class="str">"method"</span><span class="pun">:</span><span class="pln"> </span><span class=
+"str">"AudioLibrary.GetAlbums"</span><span class="pun">,</span><span class="pln"> </span><span class=
+"str">"params"</span><span class="pun">:</span><span class="pln"> </span><span class="pun">{</span><span class=
+"pln"> </span><span class="str">"genreid"</span><span class="pun">:</span><span class="pln"> </span><span class=
+"pun">-</span><span class="lit">1</span><span class="pun">,</span><span class="pln">
+         </span><span class="str">"artistid"</span><span class="pun">:</span><span class="pln"> </span><span class=
+"pun">-</span><span class="lit">1</span><span class="pun">,</span><span class="pln"> </span><span class=
+"str">"start"</span><span class="pun">:</span><span class="pln"> </span><span class="pun">-</span><span class=
+"lit">1</span><span class="pun">,</span><span class="pln"> </span><span class="str">"end"</span><span class=
+"pun">:</span><span class="pln"> </span><span class="pun">-</span><span class="lit">1</span><span class=
+"pln"> </span><span class="pun">},</span><span class="pln"> </span><span class="str">"id"</span><span class=
+"pun">:</span><span class="pln"> </span><span class="str">"1"</span><span class="pln"> </span><span class=
+"pun">}</span><span class="pln">
+   </span><span class="pun">];</span><span class="pln">
+
+   svcXhr</span><span class="pun">.</span><span class="pln">send</span><span class="pun">(</span><span class=
+"pln">JSON</span><span class="pun">.</span><span class="pln">stringify</span><span class="pun">(</span><span class=
+"pln">svcMsg</span><span class="pun">));</span><span class="pln">
+   debug</span><span class="pun">.</span><span class="pln">innerHTML </span><span class="pun">+=</span><span class=
+"pln"> </span><span class="str">"&lt;br&gt;"</span><span class="pln"> </span><span class="pun">+</span><span class=
+"pln"> services</span><span class="pun">[</span><span class="lit">0</span><span class="pun">].</span><span class=
+"pln">name </span><span class="pun">+</span><span class="pln"> </span><span class=
+"str">" request sent: "</span><span class="pun">;</span><span class="pln">
+   debug</span><span class="pun">.</span><span class="pln">textContent </span><span class="pun">+=</span><span class=
+"pln"> JSON</span><span class="pun">.</span><span class="pln">stringify</span><span class="pun">(</span><span class=
+"pln">svcMsg</span><span class="pun">);</span><span class="pln">
+
+ </span><span class="pun">}</span><span class="pln">
+
+ </span><span class="kwd">function</span><span class="pln"> error</span><span class="pun">(</span><span class=
+"pln"> err </span><span class="pun">)</span><span class="pln"> </span><span class="pun">{</span><span class="pln">
+   debug</span><span class="pun">.</span><span class="pln">innerHTML </span><span class="pun">+=</span><span class=
+"pln"> </span><span class="str">"&lt;br&gt;An error occurred obtaining a local network service."</span><span class=
+"pun">;</span><span class="pln">
+   startBtn</span><span class="pun">.</span><span class="pln">disabled </span><span class="pun">=</span><span class=
+"pln"> </span><span class="kwd">false</span><span class="pun">;</span><span class="pln">
+ </span><span class="pun">}</span><span class="pln">
+</span><span class="tag">&lt;/script&gt;</span>
+</pre>
+      </div>
+      <div class="example">
+        <p>
+          This sample exposes a drop-down list containing a number of common Home-based audio devices. When the user
+          selects an audio device from the list provided, they are prompted to authorize a network service based on the
+          service type requested. The user may also select multiple network services matching the selected service
+          type. In this example, the user selects their make as being <var>Sony</var> and their model as being
+          <var>Bravia S1000</var> from which the Web page can derive a service type
+          (<var>urn:schemas-upnp-org:service:RenderingControl:1</var>).<br>
+          <br>
+          Once the user has authorized the device, the web page sends a simple mute command according to the messaging
+          format supported by the device.
+        </p>
+        <hr>
+        <pre class="highlight prettyprint prettyprinted"
+             style="">
+<span class="tag">&lt;select</span><span class="pln"> </span><span class="atn">name</span><span class=
+"pun">=</span><span class="atv">"make"</span><span class="pln"> </span><span class="atn">id</span><span class=
+"pun">=</span><span class="atv">"make"</span><span class="tag">&gt;</span><span class="pln">
+  </span><span class="tag">&lt;option</span><span class="pln"> </span><span class="atn">selected</span><span class=
+"pun">=</span><span class="atv">"selected"</span><span class="pln"> </span><span class=
+"atn">disabled</span><span class="pun">=</span><span class="atv">"disabled"</span><span class=
+"tag">&gt;</span><span class="pln">Select make</span><span class="tag">&lt;/option&gt;</span><span class="pln">
+  </span><span class="tag">&lt;option&gt;</span><span class="pln">Sony</span><span class=
+"tag">&lt;/option&gt;</span><span class="pln">
+  </span><span class="tag">&lt;option&gt;</span><span class="pln">Philips</span><span class=
+"tag">&lt;/option&gt;</span><span class="pln">
+  </span><span class="tag">&lt;option&gt;</span><span class="pln">Alba</span><span class=
+"tag">&lt;/option&gt;</span><span class="pln">
+</span><span class="tag">&lt;/select&gt;</span><span class="pln">
+</span><span class="tag">&lt;select</span><span class="pln"> </span><span class="atn">name</span><span class=
+"pun">=</span><span class="atv">"model"</span><span class="pln"> </span><span class="atn">id</span><span class=
+"pun">=</span><span class="atv">"model"</span><span class="tag">&gt;&lt;/select&gt;</span><span class="pln">
+</span><span class="tag">&lt;div</span><span class="pln"> </span><span class="atn">id</span><span class=
+"pun">=</span><span class="atv">"debugconsole"</span><span class="tag">&gt;&lt;/div&gt;</span><span class="pln">
+
+</span><span class="tag">&lt;script&gt;</span><span class="pln">
+  </span><span class="kwd">var</span><span class="pln"> debug </span><span class="pun">=</span><span class=
+"pln"> document</span><span class="pun">.</span><span class="pln">getElementById</span><span class=
+"pun">(</span><span class="str">'debugconsole'</span><span class="pun">);</span><span class="pln">
+
+  </span><span class="kwd">var</span><span class="pln"> models </span><span class="pun">=</span><span class=
+"pln"> </span><span class="pun">{</span><span class="pln">
+    </span><span class="str">"Sony"</span><span class="pun">:</span><span class="pln"> </span><span class=
+"pun">[</span><span class="pln">
+      </span><span class="pun">{</span><span class="str">"name"</span><span class="pun">:</span><span class=
+"pln"> </span><span class="str">"Bravia TV S1000"</span><span class="pun">,</span><span class=
+"pln"> </span><span class="str">"type"</span><span class="pun">:</span><span class="pln"> </span><span class=
+"str">"upnp"</span><span class="pun">,</span><span class="pln"> </span><span class="str">"service"</span><span class=
+"pun">:</span><span class="pln"> </span><span class=
+"str">"urn:schemas-upnp-org:service:RenderingControl:1"</span><span class="pln"> </span><span class=
+"pun">},</span><span class="pln">
+      </span><span class="pun">{</span><span class="str">"name"</span><span class="pun">:</span><span class=
+"pln"> </span><span class="str">"Bravia TV S2000"</span><span class="pun">,</span><span class=
+"pln"> </span><span class="str">"type"</span><span class="pun">:</span><span class="pln"> </span><span class=
+"str">"zeroconf"</span><span class="pun">,</span><span class="pln"> </span><span class=
+"str">"service"</span><span class="pun">:</span><span class="pln"> </span><span class=
+"str">"_mediarenderer._http._tcp"</span><span class="pln"> </span><span class="pun">},</span><span class="pln">
+      </span><span class="pun">{</span><span class="str">"name"</span><span class="pun">:</span><span class=
+"pln"> </span><span class="str">"HiFi WD10"</span><span class="pun">,</span><span class="pln"> </span><span class=
+"str">"type"</span><span class="pun">:</span><span class="pln"> </span><span class="str">"upnp"</span><span class=
+"pun">,</span><span class="pln"> </span><span class="str">"service"</span><span class="pun">:</span><span class=
+"pln"> </span><span class="str">"urn:schemas-upnp-org:service:RenderingControl:1"</span><span class=
+"pln"> </span><span class="pun">}</span><span class="pln">
+    </span><span class="pun">],</span><span class="pln">
+    </span><span class="str">"Philips"</span><span class="pun">:</span><span class="pln"> </span><span class=
+"pun">[</span><span class="pln"> </span><span class="com">/* ... */</span><span class="pln"> </span><span class=
+"pun">],</span><span class="pln">
+    </span><span class="str">"Alba"</span><span class="pun">:</span><span class="pln"> </span><span class=
+"pun">[</span><span class="pln"> </span><span class="com">/* ... */</span><span class="pln"> </span><span class=
+"pun">]</span><span class="pln">
+  </span><span class="pun">};</span><span class="pln">
+
+  </span><span class="kwd">var</span><span class="pln"> makeEl </span><span class="pun">=</span><span class=
+"pln"> document</span><span class="pun">.</span><span class="pln">getElementById</span><span class=
+"pun">(</span><span class="str">"make"</span><span class="pun">),</span><span class="pln">
+      modelEl </span><span class="pun">=</span><span class="pln"> document</span><span class="pun">.</span><span class=
+"pln">getElementById</span><span class="pun">(</span><span class="str">"model"</span><span class=
+"pun">);</span><span class="pln">
+
+  makeEl</span><span class="pun">.</span><span class="pln">addEventListener</span><span class=
+"pun">(</span><span class="str">'change'</span><span class="pun">,</span><span class="pln"> </span><span class=
+"kwd">function</span><span class="pun">()</span><span class="pln"> </span><span class="pun">{</span><span class="pln">
+    modelEl</span><span class="pun">.</span><span class="pln">innerHTML </span><span class="pun">=</span><span class=
+"pln"> </span><span class="str">""</span><span class="pun">;</span><span class="pln"> </span><span class=
+"com">// reset</span><span class="pln">
+    </span><span class="kwd">var</span><span class="pln"> defaultOption </span><span class="pun">=</span><span class=
+"pln"> document</span><span class="pun">.</span><span class="pln">createElement</span><span class=
+"pun">(</span><span class="str">"option"</span><span class="pun">);</span><span class="pln">
+    defaultOption</span><span class="pun">.</span><span class="pln">textContent </span><span class=
+"pun">=</span><span class="pln"> </span><span class="str">"Select model"</span><span class="pun">;</span><span class=
+"pln">
+    defaultOption</span><span class="pun">.</span><span class="pln">setAttribute</span><span class=
+"pun">(</span><span class="str">"disabled"</span><span class="pun">,</span><span class="pln"> </span><span class=
+"str">"disabled"</span><span class="pun">);</span><span class="pln">
+    defaultOption</span><span class="pun">.</span><span class="pln">setAttribute</span><span class=
+"pun">(</span><span class="str">"selected"</span><span class="pun">,</span><span class="pln"> </span><span class=
+"str">"selected"</span><span class="pun">);</span><span class="pln">
+    modelEl</span><span class="pun">.</span><span class="pln">appendChild</span><span class="pun">(</span><span class=
+"pln">defaultOption</span><span class="pun">);</span><span class="pln">
+    </span><span class="kwd">for</span><span class="pun">(</span><span class="kwd">var</span><span class=
+"pln"> i </span><span class="pun">=</span><span class="pln"> </span><span class="lit">0</span><span class=
+"pun">,</span><span class="pln"> l </span><span class="pun">=</span><span class="pln"> models</span><span class=
+"pun">[</span><span class="pln">makeEl</span><span class="pun">.</span><span class="pln">value</span><span class=
+"pun">].</span><span class="pln">length</span><span class="pun">;</span><span class="pln"> i </span><span class=
+"pun">&lt;</span><span class="pln"> l</span><span class="pun">;</span><span class="pln"> i</span><span class=
+"pun">++)</span><span class="pln"> </span><span class="pun">{</span><span class="pln">
+      </span><span class="kwd">var</span><span class="pln"> option </span><span class="pun">=</span><span class=
+"pln"> document</span><span class="pun">.</span><span class="pln">createElement</span><span class=
+"pun">(</span><span class="str">"option"</span><span class="pun">);</span><span class="pln">
+      option</span><span class="pun">.</span><span class="pln">textContent </span><span class=
+"pun">=</span><span class="pln"> models</span><span class="pun">[</span><span class="pln">makeEl</span><span class=
+"pun">.</span><span class="pln">value</span><span class="pun">][</span><span class="pln">i</span><span class=
+"pun">][</span><span class="str">"name"</span><span class="pun">];</span><span class="pln">
+      option</span><span class="pun">.</span><span class="pln">setAttribute</span><span class=
+"pun">(</span><span class="str">"value"</span><span class="pun">,</span><span class="pln"> models</span><span class=
+"pun">[</span><span class="pln">makeEl</span><span class="pun">.</span><span class="pln">value</span><span class=
+"pun">][</span><span class="pln">i</span><span class="pun">][</span><span class="str">"type"</span><span class=
+"pun">]</span><span class="pln"> </span><span class="pun">+</span><span class="pln"> </span><span class=
+"str">":"</span><span class="pln"> </span><span class="pun">+</span><span class="pln"> models</span><span class=
+"pun">[</span><span class="pln">makeEl</span><span class="pun">.</span><span class="pln">value</span><span class=
+"pun">][</span><span class="pln">i</span><span class="pun">][</span><span class="str">"service"</span><span class=
+"pun">]);</span><span class="pln">
+      modelEl</span><span class="pun">.</span><span class="pln">appendChild</span><span class=
+"pun">(</span><span class="pln">option</span><span class="pun">);</span><span class="pln">
+    </span><span class="pun">}</span><span class="pln">
+  </span><span class="pun">},</span><span class="pln"> </span><span class="kwd">false</span><span class=
+"pun">);</span><span class="pln">
+
+  modelEl</span><span class="pun">.</span><span class="pln">addEventListener</span><span class=
+"pun">(</span><span class="str">'change'</span><span class="pun">,</span><span class="pln"> </span><span class=
+"kwd">function</span><span class="pun">()</span><span class="pln"> </span><span class="pun">{</span><span class="pln">
+    </span><span class="kwd">if</span><span class="pun">(</span><span class="pln">navigator</span><span class=
+"pun">.</span><span class="pln">getNetworkServices </span><span class="pun">&amp;&amp;</span><span class="pln">
+         modelEl</span><span class="pun">.</span><span class="pln">value </span><span class="pun">==</span><span class=
+"pln"> </span><span class="str">"upnp:urn:schemas-upnp-org:service:RenderingControl:1"</span><span class=
+"pun">)</span><span class="pln"> </span><span class="pun">{</span><span class="pln">
+      </span><span class="kwd">var</span><span class="pln"> servicesPromise </span><span class=
+"pun">=</span><span class="pln"> navigator</span><span class="pun">.</span><span class=
+"pln">getNetworkServices</span><span class="pun">(</span><span class="pln">modelEl</span><span class=
+"pun">.</span><span class="pln">value</span><span class="pun">).</span><span class="pln">then</span><span class=
+"pun">(</span><span class="pln">successCallback</span><span class="pun">,</span><span class=
+"pln"> errorCallback</span><span class="pun">);</span><span class="pln">
+    </span><span class="pun">}</span><span class="pln"> </span><span class="kwd">else</span><span class=
+"pln"> </span><span class="kwd">if</span><span class="pln"> </span><span class="pun">(</span><span class=
+"pln">modelEl</span><span class="pun">.</span><span class="pln">value </span><span class="pun">==</span><span class=
+"pln"> </span><span class="str">"zeroconf:_mediarenderer._http._tcp"</span><span class="pun">)</span><span class=
+"pln"> </span><span class="pun">{</span><span class="pln">
+      debug</span><span class="pun">.</span><span class="pln">innerHTML </span><span class="pun">+=</span><span class=
+"pln"> </span><span class="str">"&lt;br&gt;Service type is not implemented by this application."</span><span class=
+"pun">;</span><span class="pln">
+    </span><span class="pun">}</span><span class="pln"> </span><span class="kwd">else</span><span class=
+"pln"> </span><span class="pun">{</span><span class="pln">
+      debug</span><span class="pun">.</span><span class="pln">innerHTML </span><span class="pun">+=</span><span class=
+"pln"> </span><span class="str">"&lt;br&gt;Service Discovery is not supported!"</span><span class=
+"pun">;</span><span class="pln">
+    </span><span class="pun">}</span><span class="pln">
+  </span><span class="pun">},</span><span class="pln"> </span><span class="kwd">false</span><span class=
+"pun">);</span><span class="pln">
+</span><span class="tag">&lt;/script&gt;</span><span class="pln">
+
+</span><span class="tag">&lt;script&gt;</span><span class="pln">
+  </span><span class="kwd">function</span><span class="pln"> successCallback</span><span class=
+"pun">(</span><span class="pln"> services </span><span class="pun">)</span><span class="pln"> </span><span class=
+"pun">{</span><span class="pln">
+
+  </span><span class="com">// Listen for service push notification messages</span><span class="pln">
+
+    services</span><span class="pun">[</span><span class="lit">0</span><span class="pun">].</span><span class=
+"pln">addEventListener</span><span class="pun">(</span><span class="str">'notify'</span><span class=
+"pun">,</span><span class="pln"> </span><span class="kwd">function</span><span class="pln"> </span><span class=
+"pun">(</span><span class="pln"> msg </span><span class="pun">)</span><span class="pln"> </span><span class=
+"pun">{</span><span class="pln">
+         debug</span><span class="pun">.</span><span class="pln">innerHTML </span><span class=
+"pun">+=</span><span class="pln"> </span><span class="str">"&lt;br&gt;"</span><span class="pln"> </span><span class=
+"pun">+</span><span class="pln"> services</span><span class="pun">[</span><span class="lit">0</span><span class=
+"pun">].</span><span class="pln">name </span><span class="pun">+</span><span class="pln"> </span><span class=
+"str">" event received: "</span><span class="pun">;</span><span class="pln">
+         debug</span><span class="pun">.</span><span class="pln">textContent </span><span class=
+"pun">+=</span><span class="pln"> msg</span><span class="pun">.</span><span class="pln">data</span><span class=
+"pun">;</span><span class="pln">
+    </span><span class="pun">},</span><span class="pln"> </span><span class="kwd">false</span><span class=
+"pun">);</span><span class="pln">
+
+ </span><span class="com">// Send a control signal to mute the service audio</span><span class="pln">
+
+    </span><span class="kwd">var</span><span class="pln"> svcXhr </span><span class="pun">=</span><span class=
+"pln"> </span><span class="kwd">new</span><span class="pln"> </span><span class="typ">XMLHttpRequest</span><span class=
+"pun">();</span><span class="pln">
+    svcXhr</span><span class="pun">.</span><span class="pln">open</span><span class="pun">(</span><span class=
+"str">"POST"</span><span class="pun">,</span><span class="pln"> services</span><span class="pun">[</span><span class=
+"lit">0</span><span class="pun">].</span><span class="pln">url</span><span class="pun">);</span><span class=
+"pln"> </span><span class="com">// services[0].url and its sub-resources are</span><span class="pln">
+                                          </span><span class=
+"com">// available for cross-site XHR use.</span><span class="pln">
+
+    svcXhr</span><span class="pun">.</span><span class="pln">setRequestHeader</span><span class=
+"pun">(</span><span class="str">'SOAPAction'</span><span class="pun">,</span><span class="pln"> </span><span class=
+"str">'urn:schemas-upnp-org:service:RenderingControl:1#SetMute'</span><span class="pun">);</span><span class="pln">
+    svcXhr</span><span class="pun">.</span><span class="pln">setRequestHeader</span><span class=
+"pun">(</span><span class="str">'Content-Type'</span><span class="pun">,</span><span class="pln"> </span><span class=
+"str">'text/xml; charset="utf-8";'</span><span class="pun">);</span><span class="pln">
+
+    svcXhr</span><span class="pun">.</span><span class="pln">onreadystatechange </span><span class=
+"pun">=</span><span class="pln"> </span><span class="kwd">function</span><span class="pln"> </span><span class=
+"pun">(</span><span class="pln"> response </span><span class="pun">)</span><span class="pln"> </span><span class=
+"pun">{</span><span class="pln">
+      </span><span class="kwd">if</span><span class="pun">(</span><span class="pln"> response</span><span class=
+"pun">.</span><span class="pln">readyState </span><span class="pun">!=</span><span class="pln"> </span><span class=
+"lit">4</span><span class="pln"> </span><span class="pun">||</span><span class="pln"> response</span><span class=
+"pun">.</span><span class="pln">status </span><span class="pun">!=</span><span class="pln"> </span><span class=
+"lit">200</span><span class="pln"> </span><span class="pun">)</span><span class="pln">
+        </span><span class="kwd">return</span><span class="pun">;</span><span class="pln">
+      debug</span><span class="pun">.</span><span class="pln">innerHTML </span><span class="pun">+=</span><span class=
+"pln"> </span><span class="str">"&lt;br&gt;"</span><span class="pln"> </span><span class="pun">+</span><span class=
+"pln"> services</span><span class="pun">[</span><span class="lit">0</span><span class="pun">].</span><span class=
+"pln">name </span><span class="pun">+</span><span class="pln"> </span><span class=
+"str">" response received: "</span><span class="pun">;</span><span class="pln">
+      debug</span><span class="pun">.</span><span class="pln">textContent </span><span class=
+"pun">+=</span><span class="pln"> response</span><span class="pun">.</span><span class=
+"pln">responseXML</span><span class="pun">;</span><span class="pln">
+    </span><span class="pun">}</span><span class="pln">
+
+    </span><span class="com">// Service messaging to mute the provided service</span><span class="pln">
+    </span><span class="kwd">var</span><span class="pln"> svcMsg </span><span class="pun">=</span><span class=
+"pln"> </span><span class="str">'&lt;?xml version="1.0" encoding="utf-8"?&gt;'</span><span class=
+"pln"> </span><span class="pun">+</span><span class="pln">
+                 </span><span class=
+"str">'&lt;s:Envelope s:encodingStyle="http://schemas.xmlsoap.org/soap/encoding/" '</span><span class=
+"pln"> </span><span class="pun">+</span><span class="pln">
+                   </span><span class=
+"str">'xmlns:s="http://schemas.xmlsoap.org/soap/envelope/"&gt;'</span><span class="pln"> </span><span class=
+"pun">+</span><span class="pln">
+                   </span><span class="str">'&lt;s:Body&gt;'</span><span class="pln"> </span><span class=
+"pun">+</span><span class="pln">
+                     </span><span class=
+"str">'&lt;u:SetMute xmlns:u="urn:schemas-upnp-org:service:RenderingControl:1"&gt;'</span><span class=
+"pln"> </span><span class="pun">+</span><span class="pln">
+                       </span><span class="str">'&lt;InstanceID&gt;0&lt;/InstanceID&gt;'</span><span class=
+"pln"> </span><span class="pun">+</span><span class="pln">
+                       </span><span class="str">'&lt;Channel&gt;Master&lt;/Channel&gt;'</span><span class=
+"pln"> </span><span class="pun">+</span><span class="pln">
+                       </span><span class="str">'&lt;DesiredMute&gt;true&lt;/DesiredMute&gt;'</span><span class=
+"pln"> </span><span class="pun">+</span><span class="pln">
+                     </span><span class="str">'&lt;/u:SetMute&gt;'</span><span class="pln"> </span><span class=
+"pun">+</span><span class="pln">
+                   </span><span class="str">'&lt;/s:Body&gt;'</span><span class="pln"> </span><span class=
+"pun">+</span><span class="pln">
+                 </span><span class="str">'&lt;/s:Envelope&gt;'</span><span class="pun">;</span><span class="pln">
+
+    svcXhr</span><span class="pun">.</span><span class="pln">send</span><span class="pun">(</span><span class=
+"pln">svcMsg</span><span class="pun">);</span><span class="pln">
+    debug</span><span class="pun">.</span><span class="pln">innerHTML </span><span class="pun">+=</span><span class=
+"pln"> </span><span class="str">"&lt;br&gt;"</span><span class="pln"> </span><span class="pun">+</span><span class=
+"pln"> services</span><span class="pun">[</span><span class="lit">0</span><span class="pun">].</span><span class=
+"pln">name </span><span class="pun">+</span><span class="pln"> </span><span class=
+"str">" request sent: "</span><span class="pun">;</span><span class="pln">
+    debug</span><span class="pun">.</span><span class="pln">textContent </span><span class="pun">+=</span><span class=
+"pln"> svcMsg</span><span class="pun">;</span><span class="pln">
+  </span><span class="pun">}</span><span class="pln">
+
+  </span><span class="kwd">function</span><span class="pln"> errorCallback</span><span class="pun">(</span><span class=
+"pln"> error </span><span class="pun">)</span><span class="pln"> </span><span class="pun">{</span><span class="pln">
+    debug</span><span class="pun">.</span><span class="pln">innerHTML </span><span class="pun">+=</span><span class=
+"pln"> </span><span class="str">"&lt;br&gt;An error occurred: "</span><span class="pln"> </span><span class=
+"pun">+</span><span class="pln"> error</span><span class="pun">.</span><span class="pln">name</span><span class=
+"pun">;</span><span class="pln">
+  </span><span class="pun">}</span><span class="pln">
+</span><span class="tag">&lt;/script&gt;</span>
+</pre>
+      </div>
+    </section>
+    <section id="acknowledgements">
+      <h2 aria-level="1"
+          role="heading"
+          id="h2_acknowledgements">
+        <span class="secno">B.</span> Acknowledgements
+      </h2>
+      <p>
+        Thanks are expressed by the editor to the following individuals for their feedback on this specification to
+        date (in alphabetical order):<br>
+        <br>
+        Adam Barth, Gar Bergstedt, Robin Berjon, Lars-Erik Bolstad, Marcos Caceres, Cathy Chan, Daniel Danciu,
+        Jean-Claude Dufourd, Youenn Fablot, Mark Foltz, Dominique Hazael-Massieux, Frederick Hirsch, Tatsuya Igarashi,
+        Hari G Kumar, Bob Lund, Giuseppe Pascale, Marcin Simonides, Clarke Stevens, Christian Söderström, Mark Vickers.
+      </p>
+      <p>
+        Thanks are also expressed by the editor to the following organizations and groups for their support in
+        producing this specification to date (in alphabetical order):<br>
+        <br>
+        CableLabs, Google Inc., Opera Software ASA, Nokia Corp., Télécom ParisTech, <abbr title=
+        "World Wide Web Consortium">W3C</abbr> Device APIs Working Group, <abbr title=
+        "World Wide Web Consortium">W3C</abbr> Web and TV Interest Group.
+      </p>
+    </section><style>
+a.externalDFN { color: #00C; border-bottom: 1px dashed #00C; }
+    a.internalDFN { color: #00C; text-decoration: solid; }
+    </style>
+    <section id="references"
+             class="appendix"
+             typeof="bibo:Chapter"
+             resource="#ref"
+             rel="bibo:Chapter">
+      <h2 aria-level="1"
+          role="heading"
+          id="h2_references">
+        <span class="secno">C.</span> References
+      </h2>
+      <section id="normative-references"
+               typeof="bibo:Chapter"
+               resource="#ref"
+               rel="bibo:Chapter">
+        <h3 aria-level="2"
+            role="heading"
+            id="h3_normative-references">
+          <span class="secno">C.1</span> Normative references
+        </h3>
+        <dl class="bibliography"
+            about="">
+          <dt id="bib-CORS">
+            [CORS]
+          </dt>
+          <dd rel="dcterms:requires">
+            Anne van Kesteren. <a href="http://www.w3.org/TR/cors/"><cite>Cross-Origin Resource Sharing</cite></a>. 16
+            January 2014. W3C Recommendation. URL: <a href="http://www.w3.org/TR/cors/">http://www.w3.org/TR/cors/</a>
+          </dd>
+          <dt id="bib-DNS-SD">
+            [DNS-SD]
+          </dt>
+          <dd rel="dcterms:requires">
+            S. Cheshire; M. Krochmal. <a href="http://www.ietf.org/rfc/rfc6763.txt"><cite>DNS-Based Service
+            Discovery</cite></a>. February 2013. RFC. URL: <a href=
+            "http://www.ietf.org/rfc/rfc6763.txt">http://www.ietf.org/rfc/rfc6763.txt</a>
+          </dd>
+          <dt id="bib-DOM4">
+            [DOM4]
+          </dt>
+          <dd rel="dcterms:requires">
+            Anne van Kesteren; Aryeh Gregor; Ms2ger; Alex Russell; Robin Berjon. <a href=
+            "http://www.w3.org/TR/dom/"><cite>W3C DOM4</cite></a>. 4 February 2014. W3C Last Call Working Draft. URL:
+            <a href="http://www.w3.org/TR/dom/">http://www.w3.org/TR/dom/</a>
+          </dd>
+          <dt id="bib-HTML5">
+            [HTML5]
+          </dt>
+          <dd rel="dcterms:requires">
+            Robin Berjon; Steve Faulkner; Travis Leithead; Erika Doyle Navara; Edward O'Connor; Silvia Pfeiffer.
+            <a href="http://www.w3.org/TR/html5/"><cite>HTML5</cite></a>. 4 February 2014. W3C Candidate
+            Recommendation. URL: <a href="http://www.w3.org/TR/html5/">http://www.w3.org/TR/html5/</a>
+          </dd>
+          <dt id="bib-MDNS">
+            [MDNS]
+          </dt>
+          <dd rel="dcterms:requires">
+            S. Cheshire; M. Krochmal. <a href="http://www.ietf.org/rfc/rfc6763.txt"><cite>Multicast DNS</cite></a>.
+            February 2013. RFC. URL: <a href=
+            "http://www.ietf.org/rfc/rfc6763.txt">http://www.ietf.org/rfc/rfc6763.txt</a>
+          </dd>
+          <dt id="bib-RFC2119">
+            [RFC2119]
+          </dt>
+          <dd rel="dcterms:requires">
+            S. Bradner. <a href="http://www.ietf.org/rfc/rfc2119.txt"><cite>Key words for use in RFCs to Indicate
+            Requirement Levels.</cite></a> March 1997. Internet RFC 2119. URL: <a href=
+            "http://www.ietf.org/rfc/rfc2119.txt">http://www.ietf.org/rfc/rfc2119.txt</a>
+          </dd>
+          <dt id="bib-UPNP-DEVICEARCH11">
+            [UPNP-DEVICEARCH11]
+          </dt>
+          <dd rel="dcterms:requires">
+            <a href="http://upnp.org/specs/arch/UPnP-arch-DeviceArchitecture-v1.1.pdf"><cite>UPnP Device Architecture
+            1.1</cite></a>. 15 October 2008. UPnP Forum. PDF document. URL: <a href=
+            "http://upnp.org/specs/arch/UPnP-arch-DeviceArchitecture-v1.1.pdf">http://upnp.org/specs/arch/UPnP-arch-DeviceArchitecture-v1.1.pdf</a>
+          </dd>
+          <dt id="bib-WEBIDL">
+            [WEBIDL]
+          </dt>
+          <dd rel="dcterms:requires">
+            Cameron McCormack. <a href="http://www.w3.org/TR/WebIDL/"><cite>Web IDL</cite></a>. 19 April 2012. W3C
+            Candidate Recommendation. URL: <a href="http://www.w3.org/TR/WebIDL/">http://www.w3.org/TR/WebIDL/</a>
+          </dd>
+        </dl>
+      </section>
+      <section id="informative-references"
+               typeof="bibo:Chapter"
+               resource="#ref"
+               rel="bibo:Chapter">
+        <h3 aria-level="2"
+            role="heading"
+            id="h3_informative-references">
+          <span class="secno">C.2</span> Informative references
+        </h3>
+        <dl class="bibliography"
+            about="">
+          <dt id="bib-hnreq">
+            [hnreq]
+          </dt>
+          <dd rel="dcterms:references">
+            Giuseppe Pascale. <a href="http://www.w3.org/TR/hnreq/"><cite>Requirements for Home Networking
+            Scenarios</cite></a>. 1 December 2011. W3C Note. URL: <a href=
+            "http://www.w3.org/TR/hnreq/">http://www.w3.org/TR/hnreq/</a>
+          </dd>
+        </dl>
+      </section>
+    </section>
+  </body>
+</html>