Prepare Working Draft for NSD. Attach WD
authorRich Tibbett <richt@opera.com>
Tue, 02 Oct 2012 19:09:00 +0200
changeset 242 b00e3f4ff267
parent 241 985e203d74f7
child 243 220f3226b2a1
Prepare Working Draft for NSD. Attach WD
discovery-api/WD.html
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/discovery-api/WD.html	Tue Oct 02 19:09:00 2012 +0200
@@ -0,0 +1,2790 @@
+<!DOCTYPE html>
+<html lang="en"
+      dir="ltr">
+  <head>
+    <title>
+      Network Service Discovery
+    </title>
+    <meta http-equiv="Content-Type"
+          content="text/html; charset=utf-8">
+    <style type="text/css">
+/* Custom ReSpec CSS (by Rich Tibbett) */
+
+      /* Add better spacing to sections */
+      section, .section { margin-bottom: 2em; }
+
+      /* Reduce note & issue render size */
+      .note, .issue { font-size:0.8em; }
+
+      /* Add addition spacing to <ol> and <ul> for rule definition */
+      ol.rule li, ul.rule li { padding:0.6em; }
+
+      pre.widl { border: solid thin; background: #EEEEEE; color: black; padding: 0.5em 1em; position: relative; }
+      pre.widl :link, pre.widl :visited { color: #000; background: transparent; }
+      pre.widl:before { content: "IDL"; font: bold small sans-serif; padding: 0.5em; background: white; position: absolute; top: 0; margin: -1px 0 0 -4em; width: 1.5em; border: thin solid; border-radius: 0 0 0 0.5em }
+
+      div.example { border: solid thin red; background: #F7DFE5; color: black; padding: 0.5em 1em; position: relative; margin: 1em 0 1em 4.6em; width: auto; }
+      div.example:before { content: "EXAMPLE"; font: bold small sans-serif; padding: 0.5em; background: red; color: white; position: absolute; top: 0; margin: -1px 0 0 -7.6em; width: 5em; border: thin solid red; border-radius: 0 0 0 0.5em }
+
+      dl.domintro { color: green; margin: 2em 0 2em 2em; padding: 0.5em 1em; border: none; background: #DDFFDD; }
+      hr + dl.domintro, div.impl + dl.domintro { margin-top: 2.5em; margin-bottom: 1.5em; }
+      dl.domintro dt, dl.domintro dt * { color: black; text-decoration: none; }
+      dl.domintro dd { margin: 0.5em 0 1em 2em; padding: 0; }
+      dl.domintro dd p { margin: 0.5em 0; }
+      dl.domintro code {font-size: inherit; font-style: italic; }
+      dl.domintro:before { display: table; margin: -1em -0.5em 0.5em auto; width: auto; content: 'This box is non-normative. Implementation requirements are given below this box.'; color: red; border: solid 2px; background: white; padding: 0 0.25em; }
+
+      table { border-collapse:collapse; border-style:hidden hidden none hidden }
+      table thead { border-bottom:solid }
+      table tbody th:first-child { border-left:solid }
+      table td, table th { border-left:solid; border-right:solid; border-bottom:solid thin; vertical-align:top; padding:0.2em }
+    </style>
+    <style type="text/css">
+/*****************************************************************
+    * ReSpec 3 CSS
+    * Robin Berjon - http://berjon.com/
+    *****************************************************************/
+
+    /* --- INLINES --- */
+    em.rfc2119 {
+    text-transform:     lowercase;
+    font-variant:       small-caps;
+    font-style:         normal;
+    color:              #900;
+    }
+
+    h1 acronym, h2 acronym, h3 acronym, h4 acronym, h5 acronym, h6 acronym, a acronym,
+    h1 abbr, h2 abbr, h3 abbr, h4 abbr, h5 abbr, h6 abbr, a abbr {
+    border: none;
+    }
+
+    dfn {
+    font-weight:    bold;
+    }
+
+    a.internalDFN {
+    color:  inherit;
+    border-bottom:  1px solid #99c;
+    text-decoration:    none;
+    }
+
+    a.externalDFN {
+    color:  inherit;
+    border-bottom:  1px dotted #ccc;
+    text-decoration:    none;
+    }
+
+    a.bibref {
+    text-decoration:    none;
+    }
+
+    cite .bibref {
+    font-style: normal;
+    }
+
+    code {
+    color:  #ff4500;
+    }
+
+
+    /* --- --- */
+    ol.algorithm { counter-reset:numsection; list-style-type: none; }
+    ol.algorithm li { margin: 0.5em 0; }
+    ol.algorithm li:before { font-weight: bold; counter-increment: numsection; content: counters(numsection, ".") ") "; }
+
+    /* --- TOC --- */
+    .toc a, .tof a {
+    text-decoration:    none;
+    }
+
+    a .secno, a .figno {
+    color:  #000;
+    }
+
+    ul.tof, ol.tof {
+    list-style: none outside none;
+    }
+
+    .caption {
+    margin-top: 0.5em;
+    font-style:   italic;
+    }
+
+    /* --- TABLE --- */
+    table.simple {
+    border-spacing: 0;
+    border-collapse:    collapse;
+    border-bottom:  3px solid #005a9c;
+    }
+
+    .simple th {
+    background: #005a9c;
+    color:  #fff;
+    padding:    3px 5px;
+    text-align: left;
+    }
+
+    .simple th[scope="row"] {
+    background: inherit;
+    color:  inherit;
+    border-top: 1px solid #ddd;
+    }
+
+    .simple td {
+    padding:    3px 10px;
+    border-top: 1px solid #ddd;
+    }
+
+    .simple tr:nth-child(even) {
+    background: #f0f6ff;
+    }
+
+    /* --- DL --- */
+    .section dd > p:first-child {
+    margin-top: 0;
+    }
+
+    .section dd > p:last-child {
+    margin-bottom: 0;
+    }
+
+    .section dd {
+    margin-bottom:  1em;
+    }
+
+    .section dl.attrs dd, .section dl.eldef dd {
+    margin-bottom:  0;
+    }
+    </style>
+    <style type="text/css">
+/* --- ISSUES/NOTES --- */
+    div.issue-title, div.note-title {
+    padding-right:  1em;
+    min-width: 7.5em;
+    color: #b9ab2d;
+    }
+    div.issue-title { color: #e05252; }
+    div.note-title { color: #52e052; }
+    div.issue-title span, div.note-title span {
+    text-transform: uppercase;
+    }
+    div.note, div.issue {
+    margin-top: 1em;
+    margin-bottom: 1em;
+    }
+    .note > p:first-child, .issue > p:first-child { margin-top: 0 }
+    .issue, .note {
+    padding: .5em;
+    border-left-width: .5em;
+    border-left-style: solid;
+    }
+    div.issue, div.note {
+    padding: 0.5em;
+    margin: 1em 0;
+    position: relative;
+    clear: both;
+    }
+    span.note, span.issue { padding: .1em .5em .15em; }
+
+    .issue {
+    border-color: #e05252;
+    background: #fbe9e9;
+    }
+    .note {
+    border-color: #52e052;
+    background: #e9fbe9;
+    }
+
+
+    </style>
+    <style type="text/css">
+/* HIGHLIGHTS */
+    code.prettyprint {
+    color:  inherit;
+    }
+
+    /* this from google-code-prettify */
+    .pln{color:#000}@media screen{.str{color:#080}.kwd{color:#008}.com{color:#800}.typ{color:#606}.lit{color:#066}.pun,.opn,.clo{color:#660}.tag{color:#008}.atn{color:#606}.atv{color:#080}.dec,.var{color:#606}.fun{color:red}}@media print,projection{.str{color:#060}.kwd{color:#006;font-weight:bold}.com{color:#600;font-style:italic}.typ{color:#404;font-weight:bold}.lit{color:#044}.pun,.opn,.clo{color:#440}.tag{color:#006;font-weight:bold}.atn{color:#404}.atv{color:#060}}ol.linenums{margin-top:0;margin-bottom:0}li.L0,li.L1,li.L2,li.L3,li.L5,li.L6,li.L7,li.L8{list-style-type:none}li.L1,li.L3,li.L5,li.L7,li.L9{background:#eee}
+    </style>
+    <link rel="stylesheet"
+          href="http://www.w3.org/StyleSheets/TR/W3C-WD"
+          type="text/css">
+  </head>
+  <body>
+    <div class="head">
+      <p>
+        <a href="http://www.w3.org/"><img width="72"
+             height="48"
+             src="http://www.w3.org/Icons/w3c_home"
+             alt="W3C"></a>
+      </p>
+      <h1 class="title"
+          id="title">
+        Network Service Discovery
+      </h1>
+      <h2 id="w3c-working-draft-09-october-2012">
+        <abbr title="World Wide Web Consortium">W3C</abbr> Working Draft 09 October 2012
+      </h2>
+      <dl>
+        <dt>
+          This version:
+        </dt>
+        <dd>
+          <a href=
+          "http://www.w3.org/TR/2012/WD-discovery-api-20121009/">http://www.w3.org/TR/2012/WD-discovery-api-20121009/</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 href=
+          "http://www.w3.org/TR/2012/WD-discovery-api-20120807/">http://www.w3.org/TR/2012/WD-discovery-api-20120807/</a>
+        </dd>
+        <dt>
+          Editors:
+        </dt>
+        <dd>
+          <span>Rich Tibbett</span>, <a href="http://opera.com/">Opera Software ASA</a>
+        </dd>
+        <dd>
+          <span>Clarke Stevens</span>, <a href="http://cablelabs.com/">CableLabs</a>
+        </dd>
+      </dl>
+      <p class="copyright">
+        <a href="http://www.w3.org/Consortium/Legal/ipr-notice#Copyright">Copyright</a> © 2012 <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>), 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">
+      <h2>
+        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">
+      <h2>
+        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 document represents the early consensus of the group on the scope and features of the proposed
+        <abbr title="Application Programming Interface">API</abbr>.
+      </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 feedback is 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 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">
+        Table of Contents
+      </h2>
+      <ul class="toc">
+        <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="#requesting-networked-services"
+              class="tocxref"><span class="secno">4.</span> Requesting networked services</a>
+          <ul class="toc">
+            <li class="tocline">
+              <a href="#methods"
+                  class="tocxref"><span class="secno">4.1</span> Methods</a>
+            </li>
+            <li class="tocline">
+              <a href="#error-handling"
+                  class="tocxref"><span class="secno">4.2</span> Error Handling</a>
+            </li>
+          </ul>
+        </li>
+        <li class="tocline">
+          <a href="#obtaining-networked-services"
+              class="tocxref"><span class="secno">5.</span> Obtaining networked services</a>
+          <ul class="toc">
+            <li class="tocline">
+              <a href="#attributes"
+                  class="tocxref"><span class="secno">5.1</span> Attributes</a>
+            </li>
+            <li class="tocline">
+              <a href="#methods-1"
+                  class="tocxref"><span class="secno">5.2</span> Methods</a>
+            </li>
+            <li class="tocline">
+              <a href="#events"
+                  class="tocxref"><span class="secno">5.3</span> Events</a>
+            </li>
+          </ul>
+        </li>
+        <li class="tocline">
+          <a href="#communicating-with-a-networked-service"
+              class="tocxref"><span class="secno">6.</span> Communicating with a networked service</a>
+          <ul class="toc">
+            <li class="tocline">
+              <a href="#attributes-1"
+                  class="tocxref"><span class="secno">6.1</span> Attributes</a>
+            </li>
+            <li class="tocline">
+              <a href="#states"
+                  class="tocxref"><span class="secno">6.2</span> States</a>
+            </li>
+            <li class="tocline">
+              <a href="#events-1"
+                  class="tocxref"><span class="secno">6.3</span> Events</a>
+            </li>
+          </ul>
+        </li>
+        <li class="tocline">
+          <a href="#service-discovery"
+              class="tocxref"><span class="secno">7.</span> Service Discovery</a>
+          <ul class="toc">
+            <li class="tocline">
+              <a href="#zeroconf-mdns-dns-sd"
+                  class="tocxref"><span class="secno">7.1</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">7.2</span> Simple Service Discovery Protocol (<abbr title=
+                  "Simple Service Discovery Protocol">SSDP</abbr>)</a>
+            </li>
+            <li class="tocline">
+              <a href="#network-topology-monitoring"
+                  class="tocxref"><span class="secno">7.3</span> Network Topology Monitoring</a>
+            </li>
+          </ul>
+        </li>
+        <li class="tocline">
+          <a href="#events-summary"
+              class="tocxref"><span class="secno">8.</span> Events Summary</a>
+        </li>
+        <li class="tocline">
+          <a href="#garbage-collection"
+              class="tocxref"><span class="secno">9.</span> Garbage collection</a>
+        </li>
+        <li class="tocline">
+          <a href="#use-cases-and-requirements"
+              class="tocxref"><span class="secno">10.</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>
+          </ul>
+        </li>
+      </ul>
+    </section>
+    <section class="informative"
+             id="introduction">
+      <h2>
+        <span class="secno">1.</span> Introduction
+      </h2>
+      <p>
+        <em>This section is non-normative.</em>
+      </p>
+      <p>
+        To enable Web pages to connect and communicate with Local-networked Services provided over <abbr title=
+        "Hypertext Transfer Protocol">HTTP</abbr>, this specification introduces the <a href=
+        "#navigatornetworkservice"><code>NavigatorNetworkService</code></a> interface.
+      </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 one or more 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 Service Discovery mechanisms
+        included in this recommendation, attempts to match the requested service type to a discovered service according
+        to the processing described herein.
+      </p>
+      <p>
+        If a service connectivity request is successful then the Web page is provided with the necessary information to
+        communicate with the authorized Local-networked Service. If the request fails then the Web page will receive an
+        error callback containing an error code 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>
+      <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">
+<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=
+"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">
+<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">code </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="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">
+<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="pln"> showServices</span><span class="pun">);</span>
+</pre>
+      </div>
+      <p>
+        For more detailed examples see the <a href="#examples">Examples</a> section.
+      </p>
+    </section>
+    <section id="conformance">
+      <h2>
+        <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>
+          <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>
+        <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 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.
+      </p>
+      <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 <abbr title="Uniform Resource Locator">URL</abbr> 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>
+    </section>
+    <section id="requesting-networked-services">
+      <h2>
+        <span class="secno">4.</span> Requesting networked services
+      </h2>
+      <pre class="widl">
+[Supplemental, NoInterfaceObject]
+interface <dfn id="navigatornetworkservice">NavigatorNetworkService</dfn> {
+  // Obtain a Local-networked Service
+  void <a href="#dom-navigator-getnetworkservices">getNetworkServices</a>( in any type,
+                           in <a href=
+"#navigatornetworkservicesuccesscallback">NavigatorNetworkServiceSuccessCallback</a> successCallback,
+                           in optional <a href=
+"#navigatornetworkserviceerrorcallback">NavigatorNetworkServiceErrorCallback</a> errorCallback );
+};
+<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>;
+
+[Callback=FunctionOnly, NoInterfaceObject]
+interface <dfn id="navigatornetworkservicesuccesscallback">NavigatorNetworkServiceSuccessCallback</dfn> {
+  void handleEvent( in <a href="#networkservices">NetworkServices</a> services );
+};
+
+[NoInterfaceObject]
+interface <dfn id="navigatornetworkserviceerror">NavigatorNetworkServiceError</dfn> {
+  const unsigned short <a href="#dom-navigatornetworkserviceerror-permission_denied">PERMISSION_DENIED_ERR</a> = 1;
+  const unsigned short <a href="#dom-navigatornetworkserviceerror-unknown_type_prefix">UNKNOWN_TYPE_PREFIX_ERR</a> = 2;
+  readonly attribute unsigned short <a href="#dom-navigatornetworkserviceerror-code">code</a>;
+};
+
+[Callback=FunctionOnly, NoInterfaceObject]
+interface <dfn id="navigatornetworkserviceerrorcallback">NavigatorNetworkServiceErrorCallback</dfn> {
+  void handleEvent( in <a href="#navigatornetworkserviceerror">NavigatorNetworkServiceError</a> error );
+};
+</pre>
+      <section id="methods">
+        <h3>
+          <span class="secno">4.1</span> Methods
+        </h3>
+        <dl class="domintro">
+          <dt>
+            <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> , <var title=
+            "">successCallback</var> [, <var title="">errorCallback</var> ] )
+          </dt>
+          <dd>
+            <p>
+              Prompts the user to select one or more discovered network services that have advertised support for the
+              requested service type.
+            </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="">successCallback</var> is invoked, with one or more <a href=
+              "#networkservice"><code>NetworkService</code></a> objects as its argument.
+            </p>
+            <p>
+              If the user declines, the <var title="">errorCallback</var> (if any) is invoked.
+            </p>
+          </dd>
+        </dl>
+        <div>
+          <p>
+            When the <dfn id="dom-navigator-getnetworkservices"
+               title="dom-navigator-getnetworkservices"><code>getNetworkServices(type, successCallback[,
+               errorCallback])</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>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> by 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, the <a href="#dfn-user-agent"
+                  class="internalDFN">user agent</a> <em class="rfc2119"
+                  title="must">must</em> <a href=
+                  "http://www.whatwg.org/specs/web-apps/current-work/complete/webappapis.html#queue-a-task"
+                  class="externalDFN">queue a task</a> to invoke <var>errorCallback</var>, if it is provided and is an
+                  object of type <code>Function</code>, with a new <a href=
+                  "#navigatornetworkserviceerror"><code>NavigatorNetworkServiceError</code></a> object whose <a href=
+                  "#dom-navigatornetworkserviceerror-code"><code>code</code></a> attribute has the numeric value 2
+                  (<a href=
+                  "#dom-navigatornetworkserviceerror-unknown_type_prefix"><code>UNKNOWN_TYPE_PREFIX_ERR</code></a>) as
+                  its argument, 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> and continue at the step
+                  labeled <var>attach</var> below.
+                </li>
+                <li>Continue at the next <var>available service</var>.
+                </li>
+                <li>
+                  <em>Attach</em>: If <var>matched service</var> is not empty then run the following steps:
+                  <ol class="rule">
+                    <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>If <var>services found</var> is an empty array, then the <a href="#dfn-user-agent"
+                  class="internalDFN">user agent</a> <em class="rfc2119"
+                  title="must">must</em> <a href=
+                  "http://www.whatwg.org/specs/web-apps/current-work/complete/webappapis.html#queue-a-task"
+                  class="externalDFN">queue a task</a> to invoke <var>errorCallback</var>, if it is provided and is an
+                  object of type <code>Function</code>, with a new <a href=
+                  "#navigatornetworkserviceerror"><code>NavigatorNetworkServiceError</code></a> object whose <a href=
+                  "#dom-navigatornetworkserviceerror-code"><code>code</code></a> attribute has the numeric value 1
+                  (<a href=
+                  "#dom-navigatornetworkserviceerror-permission_denied"><code>PERMISSION_DENIED_ERR</code></a>) as its
+                  argument, abort any remaining steps and return.
+            </li>
+            <li>Return, and run the remaining steps asynchronously.
+            </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> <a href=
+                  "http://www.whatwg.org/specs/web-apps/current-work/complete/webappapis.html#queue-a-task"
+                  class="externalDFN">queue a task</a> to invoke <var>errorCallback</var>, if it is provided and is an
+                  object of type <code>Function</code>, with a new <a href=
+                  "#navigatornetworkserviceerror"><code>NavigatorNetworkServiceError</code></a> object whose <a href=
+                  "#dom-navigatornetworkserviceerror-code"><code>code</code></a> attribute has the numeric value 1
+                  (<a href=
+                  "#dom-navigatornetworkserviceerror-permission_denied"><code>PERMISSION_DENIED_ERR</code></a>) as its
+                  argument, abort any remaining steps and return.
+            </li>
+            <li>The <a href="#dfn-user-agent"
+                  class="internalDFN">user agent</a> <em class="rfc2119"
+                  title="must">must</em> 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 an array of <a href=
+                  "#networkservice"><code>NetworkService</code></a> objects representing the user-authorized subset of
+                  <var>services found</var>.
+              <p>
+                If the user grants permission 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 the user denies permission, then the <a href="#dfn-user-agent"
+                   class="internalDFN">user agent</a> <em class="rfc2119"
+                   title="must">must</em> <a href=
+                   "http://www.whatwg.org/specs/web-apps/current-work/complete/webappapis.html#queue-a-task"
+                   class="externalDFN">queue a task</a> to invoke <var>errorCallback</var>, if it is provided and is an
+                   object of type <code>Function</code>, with a new <a href=
+                   "#navigatornetworkserviceerror"><code>NavigatorNetworkServiceError</code></a> object whose <a href=
+                   "#dom-navigatornetworkserviceerror-code"><code>code</code></a> attribute has the numeric value 1
+                   (<a href=
+                   "#dom-navigatornetworkserviceerror-permission_denied"><code>PERMISSION_DENIED_ERR</code></a>) as its
+                   argument, abort any remaining steps and return.
+              </p>
+              <p>
+                If the user never responds, this algorithm stalls on this step.
+              </p>
+            </li>
+            <li>Let <var>services</var> be the array of one or more <a href=
+            "#networkservice"><code>NetworkService</code></a> objects for which the user granted permission.
+            </li>
+            <li>For each Object <var>service</var> in <var>services</var>, run the following sub-steps:
+              <ol class="rule">
+                <li>Add the <var>service</var>'s <code>url</code> parameter to the <a href=
+                "#dfn-entry-script-origin-s-url-whitelist"
+                      class="internalDFN">entry script origin's <abbr title="Uniform Resource Locator">URL</abbr>
+                      whitelist</a>.
+                </li>
+                <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>Set <var>services manager</var>'s <a href=
+            "#dom-networkservices-servicesavailable"><code>servicesAvailable</code></a> attribute to the number of
+            services 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 the set of <var>services</var> to the <a href="#dfn-list-of-authorized-service-records"
+                  class="internalDFN">list of authorized service records</a> internally against the newly created
+                  <var>services manager</var> object.
+            </li>
+            <li>The <a href="#dfn-user-agent"
+                  class="internalDFN">user agent</a> <em class="rfc2119"
+                  title="must">must</em> <a href=
+                  "http://www.whatwg.org/specs/web-apps/current-work/complete/webappapis.html#queue-a-task"
+                  class="externalDFN">queue a task</a> to invoke <var>successCallback</var> with <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>
+            When a <a href="#networkservice"><code>NetworkService</code></a> object is provided to a Web page, the
+            <a href="#dfn-user-agent"
+               class="internalDFN">user agent</a> <em class="rfc2119"
+               title="must">must</em> add the <code>url</code> property to the <dfn id=
+               "dfn-entry-script-origin-s-url-whitelist">entry script origin's <abbr title=
+               "Uniform Resource Locator">URL</abbr> whitelist</dfn>. This list enables the Web page to override and
+               initiate cross-site resource requests towards these URLs, and any sub-resources of these URLs, within
+               the current <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> via various existing mechanisms (e.g. Web Sockets, Server-Sent Events,
+               Web Messaging, XMLHttpRequest).
+          </p>
+          <p>
+            If the user navigates away from the current browsing context, the <a href="#dfn-user-agent"
+               class="internalDFN">user agent</a> <em class="ct"><em class="rfc2119"
+                title="must">must</em></em> remove all previously whitelisted urls from the <a href=
+                "#dfn-entry-script-origin-s-url-whitelist"
+               class="internalDFN">entry script origin's <abbr title="Uniform Resource Locator">URL</abbr>
+               whitelist</a>. There is no persistence to network service selections provided to a web page. It is not
+               possible to access a previously white-listed networked service without the necessary 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>
+          <span class="secno">4.2</span> Error Handling
+        </h3>
+        <dl class="domintro">
+          <dt>
+            <var title="">error</var> . <code title="dom-NavigatorNetworkServiceError-code"><a href=
+            "#dom-navigatornetworkserviceerror-code">code</a></code>
+          </dt>
+          <dd>
+            <p>
+              Returns the current error's error code. At the current time, this will be <code>1</code> or
+              <code>2</code>, for which the corresponding error constants <a href=
+              "#dom-navigatornetworkserviceerror-permission_denied"><code>PERMISSION_DENIED_ERR</code></a> and <a href=
+              "#dom-navigatornetworkserviceerror-unknown_type_prefix"><code>UNKNOWN_TYPE_PREFIX_ERR</code></a> are
+              defined.
+            </p>
+          </dd>
+        </dl>
+        <p>
+          The <dfn id="dom-navigatornetworkserviceerror-code"
+             title="dom-navigatornetworkserviceerror-code"><code>code</code></dfn> attribute of a <a href=
+             "#navigatornetworkserviceerror"><code>NavigatorNetworkServiceError</code></a> object <em class=
+             "ct"><em class="rfc2119"
+              title="must">must</em></em> return the code for the error, which will be one of the following:
+        </p>
+        <dl>
+          <dt>
+            <dfn id="dom-navigatornetworkserviceerror-permission_denied"
+                title="dom-navigatornetworkserviceerror-permission_denied"><code>PERMISSION_DENIED_ERR</code></dfn>
+                (numeric value 1)
+          </dt>
+          <dd>
+            The user or user agent denied the page permission to access any services.
+          </dd>
+          <dt>
+            <dfn id="dom-navigatornetworkserviceerror-unknown_type_prefix"
+                title="dom-navigatornetworkserviceerror-unknown_type_prefix"><code>UNKNOWN_TYPE_PREFIX_ERR</code></dfn>
+                (numeric value 2)
+          </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>
+        <span class="secno">5.</span> Obtaining networked services
+      </h2>
+      <p>
+        The <a href="#networkservices"><code>NetworkServices</code></a> interface is the top-level response object from
+        a call to <a href="#dom-navigator-getnetworkservices"><code>getNetworkServices()</code></a> and provides access
+        to a set of user-authorized <a href="#networkservice"><code>NetworkService</code></a> objects for the given
+        request.
+      </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-onserviceavailable">onserviceavailable</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-onserviceunavailable">onserviceunavailable</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>
+          <span class="secno">5.1</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 services belonging in the respective object's <a href=
+              "#dfn-list-of-authorized-service-records"
+                 class="internalDFN">list of authorized service records</a>.
+            </p>
+          </dd>
+          <dt>
+            <code title="dom-networkservices-servicesavailable"><a href=
+            "#dom-networkservices-servicesavailable">servicesAvailable</a></code>
+          </dt>
+          <dd>
+            <p>
+              Returns the current number of services 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 services represented in the object's corresponding <a href=
+               "#dfn-list-of-authorized-service-records"
+               class="internalDFN">list of authorized service records</a> at the time of getting.
+          </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 was initially used to create the current <a href=
+               "#networkservices"><code>NetworkServices</code></a> object.
+          </p>
+        </div>
+      </section>
+      <section id="methods-1">
+        <h3>
+          <span class="secno">5.2</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 list of one or
+          more current authorized services - the <a href="#dfn-list-of-authorized-service-records"
+             class="internalDFN">list of authorized service records</a>. Each item in the <a href=
+             "#dfn-list-of-authorized-service-records"
+             class="internalDFN">list of authorized service records</a> is represented by a <a href=
+             "#networkservice"><code>NetworkService</code></a> object. The <a href=
+             "#dfn-list-of-authorized-service-records"
+             class="internalDFN">list of authorized service records</a> is <span>immutable</span> meaning that it
+             cannot be modified for the lifetime of a <a href="#networkservices"><code>NetworkServices</code></a>
+             object.
+        </p>
+        <div class="note">
+          <div class="note-title">
+            <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>
+          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 items in the <a href="#dfn-list-of-authorized-service-records"
+             class="internalDFN">list of authorized service records</a> represented by the respective object minus one,
+             if any services are represented in the <a href="#dfn-list-of-authorized-service-records"
+             class="internalDFN">list of authorized service records</a>.
+        </p>
+        <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's <a href=
+             "#dfn-list-of-authorized-service-records"
+             class="internalDFN">list of authorized service records</a>, 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 service in the <a href="#dfn-list-of-authorized-service-records"
+             class="internalDFN">list of authorized service records</a>.
+        </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 <a href="#dfn-list-of-authorized-service-records"
+             class="internalDFN">list of authorized service records</a> represented by the respective object whose
+             <a href="#dom-networkservice-id"><code>id</code></a> attribute is equal to the value of the <var>id</var>
+             argument. When no services in the <a href="#dfn-list-of-authorized-service-records"
+             class="internalDFN">list of authorized service records</a> match the given argument, the method <em class=
+             "rfc2119"
+             title="must">must</em> return null.
+        </p>
+        <p>
+          Services available within the local network can connect and disconnect at different times during the
+          execution of a web page. A <a href="#dfn-user-agent"
+             class="internalDFN">user agent</a> can inform a web page when the state of networked services matching the
+             requested <a href="#dfn-valid-service-type"
+             class="internalDFN">valid service type</a> 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.
+        </p>
+      </section>
+      <section id="events">
+        <h3>
+          <span class="secno">5.3</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"
+               summary="Event handlers for NetworkServices objects">
+          <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-onserviceavailable"
+                    title="dom-NetworkServices-onserviceavailable"><code>onserviceavailable</code></dfn>
+              </td>
+              <td>
+                <a href="#event-serviceavailable"><code>serviceavailable</code></a>
+              </td>
+            </tr>
+            <tr>
+              <td>
+                <dfn id="dom-networkservices-onserviceunavailable"
+                    title="dom-NetworkServices-onserviceunavailable"><code>onserviceunavailable</code></dfn>
+              </td>
+              <td>
+                <a href="#event-serviceunavailable"><code>serviceunavailable</code></a>
+              </td>
+            </tr>
+          </tbody>
+        </table>
+      </section>
+    </section>
+    <section id="communicating-with-a-networked-service">
+      <h2>
+        <span class="secno">6.</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-onserviceonline">onserviceonline</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-onserviceoffline">onserviceoffline</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>
+          <span class="secno">6.1</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 <abbr title="Uniform Resource Locator">URL</abbr> endpoint (including any required port
+              information) of the user-selected control service that has been added to the <a href=
+              "#dfn-entry-script-origin-s-url-whitelist"
+                 class="internalDFN">entry script origin's <abbr title="Uniform Resource Locator">URL</abbr>
+                 whitelist</a>.
+            </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://www.w3.org/TR/html5/urls.html#absolute-url"
+             class="externalDFN">absolute <abbr title="Uniform Resource Locator">URL</abbr></a> pointing to the root
+             <abbr title="Hypertext Transfer Protocol">HTTP</abbr> endpoint for the service that has been added to the
+             <a href="#dfn-entry-script-origin-s-url-whitelist"
+             class="internalDFN">entry script origin's <abbr title="Uniform Resource Locator">URL</abbr> whitelist</a>.
+             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>
+          <span class="secno">6.2</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 reporting that it 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
+          reporting itself as being 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>
+          <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=
+              "#networkservice"><code>NetworkService</code></a> interface:
+        </p>
+        <table border="1"
+               summary="Event handlers for NetworkService objects">
+          <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-onserviceonline"
+                    title="dom-NetworkService-onserviceonline"><code>onserviceonline</code></dfn>
+              </td>
+              <td>
+                <a href="#event-serviceonline"><code>serviceonline</code></a>
+              </td>
+            </tr>
+            <tr>
+              <td>
+                <dfn id="dom-networkservice-onserviceoffline"
+                    title="dom-NetworkService-onserviceoffline"><code>onserviceoffline</code></dfn>
+              </td>
+              <td>
+                <a href="#event-serviceoffline"><code>serviceoffline</code></a>
+              </td>
+            </tr>
+          </tbody>
+        </table>
+      </section>
+    </section>
+    <section id="service-discovery">
+      <h2>
+        <span class="secno">7.</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 <acronym title="Simple Service Discovery Protocol"><abbr title=
+           "Simple Service Discovery Protocol">SSDP</abbr></acronym> [<cite><a class="bibref"
+           href="#bib-UPNP-DEVICEARCH11">UPNP-DEVICEARCH11</a></cite>] and Zeroconf [<cite><a class="bibref"
+           href="#bib-DNS-SD">DNS-SD</a></cite>] + [<cite><a class="bibref"
+           href="#bib-MDNS">MDNS</a></cite>] service discovery mechanisms to enable Web pages to request and connect
+           with <abbr title="Hypertext Transfer Protocol">HTTP</abbr> services running on networked devices, discovered
+           via either mechanism, through this <abbr title="Application Programming Interface">API</abbr>. When a
+           <a href="#dfn-user-agent"
+           class="internalDFN">user agent</a> implements either of these service discovery mechanisms, 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 two service discovery mechanisms will be matched to requested
+        service types, how the user agent stores available and active services, 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 service discovery mechanisms asynchronously and periodically
+        update the <a>list of networked devices</a> as required. The timing of any service discovery mechanisms is an
+        implementation detail left to the discretion of the implementer (e.g. once on user agent start-up, every X
+        seconds during user agent execution 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 any given time. At any point during the running of either of the two
+        service discovery mechanisms 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-authorized-service-records">list of authorized service records</dfn> is a single
+        dynamic internal lookup table within user agents that is used to track the current services that are being
+        shared with web pages at any given time from the <a href="#dfn-list-of-available-service-records"
+           class="internalDFN">list of available service records</a>. Each record in the <a href=
+           "#dfn-list-of-authorized-service-records"
+           class="internalDFN">list of authorized service records</a> is associated with a <var>services manager</var>
+           object that is assigned 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 new service or updating an existing service in the <a href="#dfn-list-of-available-service-records"
+           class="internalDFN">list of available service records</a> that is generally available on the user's current
+           network. This rule takes one argument, <var>network service record</var>, and consists of running the
+           following steps:
+      </p>
+      <ol class="rule">
+        <li>Let <var>new service registration flag</var> be <code>true</code>.
+        </li>
+        <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>Set <var>new service registration flag</var> to <code>false</code>.
+            </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>.
+            </li>
+          </ol>
+        </li>
+        <li>If <var>new service registration flag</var> is set to <code>true</code> then 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 entry.
+        </li>
+        <li>For each <var>active service</var> in the <a href="#dfn-list-of-authorized-service-records"
+              class="internalDFN">list of authorized service records</a> run the following steps:
+          <ol class="rule">
+            <li>If <var>network service record</var>'s <code>type</code> property does not equal the current
+            <var>active service</var>'s <code>type</code> attribute then abort any remaining sub-steps for this
+            <var>active service</var> and continue at the next available <var>active service</var>.
+            </li>
+            <li>If the <var>new service registration flag</var> is set to <code>true</code> then increment the
+              <a href="#dom-networkservices-servicesavailable"><code>servicesAvailable</code></a> attribute of the
+              <var>services manager</var> associated with the current <var>active service</var> object 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-serviceavailable"><code>serviceavailable</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 <var>services manager</var> associated with the current <var>active
+                  service</var> object.
+            </li>
+            <li>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-serviceonline"><code>serviceonline</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>
+      </ol>
+      <p>
+        The rule for <dfn id="dfn-removing-an-available-service">removing an available service</dfn> is the general
+        process of removing a service 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>If 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>For each <var>active service</var> in <a href="#dfn-list-of-authorized-service-records"
+                  class="internalDFN">list of authorized service records</a> run the following steps:
+              <ol class="rule">
+                <li>If <var>existing service record</var>'s <code>type</code> property does not equal the current <var>
+                  active service</var>'s <code>type</code> attribute then abort any remaining sub-steps for this
+                  <var>active service</var> and continue at the next available <var>active service</var>.
+                </li>
+                <li>Decrement the <a href="#dom-networkservices-servicesavailable"><code>servicesAvailable</code></a>
+                attribute of the <var>services manager</var> associated with the current <var>active service</var>
+                object 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-serviceunavailable"><code>serviceunavailable</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 <var>services manager</var> associated with the current
+                      <var>active service</var> object.
+                </li>
+                <li>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-serviceoffline"><code>serviceoffline</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>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>
+          <span class="secno">7.1</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
+              <abbr title="Uniform Resource Locator">URL</abbr> 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>
+          <span class="secno">7.2</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 an <dfn id="dfn-advertisement-for-upnp-root-devices">advertisement 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="advertisement for UPnP root devices"
+             href="#dfn-advertisement-for-upnp-root-devices"
+             class="internalDFN">advertisements 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>, a MAN header equal to <code>ssdp:discover</code>,
+             an ST header equal to <code>upnp:rootdevice</code> and a user-agent defined 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.
+        </p>
+        <p>
+          The user agent <em class="rfc2119"
+             title="must">must</em> listen for incoming requests and process any incoming responses to any <a href=
+             "#dfn-advertisement-for-upnp-root-devices"
+             class="internalDFN">advertisement for UPnP root devices</a> 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>, according to the rules defined in this section.
+        </p>
+        <p>
+          For each <dfn id="dfn-http-response"><abbr title="Hypertext Transfer Protocol">HTTP</abbr> Response</dfn>
+          following an initial <a href="#dfn-advertisement-for-upnp-root-devices"
+             class="internalDFN">advertisement 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-advertisement-for-upnp-root-devices"
+                class="internalDFN">advertisement 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-advertisement-for-upnp-root-devices"
+                class="internalDFN">advertisement 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.
+          </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 or the
+          value of its <var>ST</var> entry is not <code>upnp:rootdevice</code>, 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 <abbr title=
+                "Uniform Resource Locator">URL</abbr></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> as the <var>device expiry</var> argument.
+          </li>
+        </ol>
+        <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> return a <abbr title="Hypertext Transfer Protocol">HTTP</abbr> 200 OK response,
+                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> 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 or the value of its <var>NT</var> entry is not <code>upnp:rootdevice</code>, then
+          the <a href="#dfn-http-request"
+                class="internalDFN"><abbr title="Hypertext Transfer Protocol">HTTP</abbr> Request</a> is a malformed
+                UPnP Request and the <a href="#dfn-user-agent"
+                class="internalDFN">user agent</a> <em class="rfc2119"
+                title="must">must</em> return a 400 Bad Request response, 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> or
+          <code>ssdp:update</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 <abbr title=
+                "Uniform Resource Locator">URL</abbr></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> 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 <abbr title=
+             "Uniform Resource Locator">URL</abbr>-based resource. This rule takes three arguments - <var>device
+             descriptor <abbr title="Uniform Resource Locator">URL</abbr></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 <abbr title=
+          "Uniform Resource Locator">URL</abbr> provided in <var>device descriptor <abbr title=
+          "Uniform Resource Locator">URL</abbr></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 <abbr title="Uniform Resource Locator">URL</abbr></var>
+          cannot be resolved as a reachable <abbr title="Uniform Resource Locator">URL</abbr> on the current network or
+          the <var>root 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>
+          <li>If the current <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 common
+                <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
+              <var>device identifier</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>
+        </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 <abbr title="Uniform Resource Locator">URL</abbr></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 <abbr title=
+          "Uniform Resource Locator">URL</abbr></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, if it exists. All other <abbr title=
+                  "Hypertext Transfer Protocol">HTTP</abbr> responses should cause the <a href="#dfn-user-agent"
+                        class="internalDFN">user agent</a> to 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 <abbr title="Uniform Resource Locator">URL</abbr></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>
+                </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 any <var>active service</var> in the <a href="#dfn-list-of-authorized-service-records"
+             class="internalDFN">list of authorized service records</a> 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="network-topology-monitoring">
+        <h3>
+          <span class="secno">7.3</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 their 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>, the user agent <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-authorized-service-records"
+               class="internalDFN">list of authorized service records</a> currently in use.
+          </p>
+        </div>
+      </section>
+    </section>
+    <section id="events-summary">
+      <h2>
+        <span class="secno">8.</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"
+             summary="Events Summary table">
+        <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-serviceavailable"><code>serviceavailable</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 new service that matches one of the <a>requested type tokens</a> is found in the current network.
+            </td>
+          </tr>
+          <tr>
+            <td>
+              <dfn id="event-serviceunavailable"><code>serviceunavailable</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 existing service that matches one of the <a>requested type tokens</a> gracefully leaves or
+              expires from the current network.
+            </td>
+          </tr>
+          <tr>
+            <td>
+              <dfn id="event-serviceonline"><code>serviceonline</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 current service renews its service registration within the current network.
+            </td>
+          </tr>
+          <tr>
+            <td>
+              <dfn id="event-serviceoffline"><code>serviceoffline</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 current service 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 current service. This event never
+                  fires for Zeroconf-based services.
+            </td>
+          </tr>
+        </tbody>
+      </table>
+    </section>
+    <section id="garbage-collection">
+      <h2>
+        <span class="secno">9.</span> Garbage collection
+      </h2>
+      <p>
+        Only when the user navigates away from the current browsing context can <a href="#networkservice"
+           class="internalDFN"><code>NetworkService</code></a> objects be garbage-collected, its records in the <a href=
+           "#dfn-entry-script-origin-s-url-whitelist"
+           class="internalDFN">entry script origin's <abbr title="Uniform Resource Locator">URL</abbr> whitelist</a> be
+           removed and its corresponding entry in the <a href="#dfn-list-of-authorized-service-records"
+           class="internalDFN">list of authorized service records</a> be removed according to passing each expired
+           object identifier through the rule for <a href="#dfn-removing-an-available-service"
+           class="internalDFN">removing an available service</a>.
+      </p>
+    </section>
+    <section id="use-cases-and-requirements">
+      <h2>
+        <span class="secno">10.</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>
+        <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">
+<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"> gotXBMCService</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">'serviceoffline'</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 have been</span><span class="pln">
+                                                        </span><span class=
+"com">// whitelisted for cross-site XHR use in this</span><span class="pln">
+                                                        </span><span class=
+"com">// current browsing context.</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">
+<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">
+      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"> 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</span><span class="pln">
+                                          </span><span class=
+"com">// sub-resources have been whitelisted for</span><span class="pln">
+                                          </span><span class=
+"com">// cross-site XHR use in this current</span><span class="pln">
+                                          </span><span class="com">// browsing context.</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">code</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>
+        <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>
+        Gar Bergstedt, Lars-Erik Bolstad, Cathy Chan, 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, Opera Software ASA, <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>
+    <section id="references"
+             class="appendix">
+      <h2>
+        <span class="secno">C.</span> References
+      </h2>
+      <section id="normative-references">
+        <h3>
+          <span class="secno">C.1</span> Normative references
+        </h3>
+        <dl class="bibliography">
+          <dt id="bib-DNS-SD">
+            [DNS-SD]
+          </dt>
+          <dd>
+            S. Cheshire; M. Krochmal. <a href=
+            "http://files.dns-sd.org/draft-cheshire-dnsext-dns-sd.txt"><cite>DNS-Based Service Discovery.</cite></a> 27
+            February 2011. IETF Draft. URL: <a href=
+            "http://files.dns-sd.org/draft-cheshire-dnsext-dns-sd.txt">http://files.dns-sd.org/draft-cheshire-dnsext-dns-sd.txt</a>
+          </dd>
+          <dt id="bib-DOM4">
+            [DOM4]
+          </dt>
+          <dd>
+            Anne van Kesteren; Aryeh Gregor; Ms2ger. <a href=
+            "http://dvcs.w3.org/hg/domcore/raw-file/tip/Overview.html/"><cite>DOM4.</cite></a> URL: <a href=
+            "http://dvcs.w3.org/hg/domcore/raw-file/tip/Overview.html/">http://dvcs.w3.org/hg/domcore/raw-file/tip/Overview.html/</a>
+          </dd>
+          <dt id="bib-HTML5">
+            [HTML5]
+          </dt>
+          <dd>
+            Ian Hickson; David Hyatt. <a href="http://www.w3.org/TR/html5"><cite>HTML5.</cite></a> 29 March 2012. W3C
+            Working Draft. (Work in progress.) URL: <a href="http://www.w3.org/TR/html5">http://www.w3.org/TR/html5</a>
+          </dd>
+          <dt id="bib-MDNS">
+            [MDNS]
+          </dt>
+          <dd>
+            S. Cheshire; M. Krochmal. <a href=
+            "http://files.multicastdns.org/draft-cheshire-dnsext-multicastdns.txt"><cite>Multicast DNS.</cite></a> 14
+            February 2011. IETF Draft. URL: <a href=
+            "http://files.multicastdns.org/draft-cheshire-dnsext-multicastdns.txt">http://files.multicastdns.org/draft-cheshire-dnsext-multicastdns.txt</a>
+          </dd>
+          <dt id="bib-RFC2119">
+            [RFC2119]
+          </dt>
+          <dd>
+            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>
+            <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>
+            Cameron McCormack. <a href="http://www.w3.org/TR/2011/WD-WebIDL-20110927/"><cite>Web IDL.</cite></a> 27
+            September 2011. W3C Working Draft. (Work in progress.) URL: <a href=
+            "http://www.w3.org/TR/2011/WD-WebIDL-20110927/">http://www.w3.org/TR/2011/WD-WebIDL-20110927/</a>
+          </dd>
+        </dl>
+      </section>
+    </section>
+  </body>
+</html>