timestamped microdata-rdf WD for comment
authorGregg Kellogg <gregg@kellogg-assoc.com>
Wed, 19 Sep 2012 22:49:41 -0700
changeset 147 4cbadf558c97
parent 146 461b60f5934e
child 148 d9b5451b0c72
timestamped microdata-rdf WD for comment
ED/microdata-rdf/20120919/diff-20120308.html
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+</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">Microdata to RDF</h1>
+  
+    <h2 id="subtitle">Transformation from HTML+Microdata to RDF</h2>
+  
+  <h2 id="w3c-working-draft-19-september-2012"><abbr title="World Wide Web Consortium">W3C</abbr> Working Draft 19 September 2012</h2>
+  <dl>
+    
+      <dt>This version:</dt>
+      <dd><a href="http://www.w3.org/TR/2012/WD-microdata-rdf-20120919/">http://www.w3.org/TR/2012/WD-microdata-rdf-20120919/</a></dd>
+      <dt>Latest published version:</dt>
+      <dd><a href="http://www.w3.org/TR/microdata-rdf/">http://www.w3.org/TR/microdata-rdf/</a></dd>
+    
+    
+      <dt>Latest editor's draft:</dt>
+      <dd><a href="http://dvcs.w3.org/hg/htmldata/raw-file/default/microdata-rdf/index.html">http://dvcs.w3.org/hg/htmldata/raw-file/default/microdata-rdf/index.html</a></dd>
+    
+    
+    
+    
+    
+      <dt>Previous version:</dt>
+      <dd><a href="http://www.w3.org/TR/2012/NOTE-microdata-rdf-20120308/">http://www.w3.org/TR/2012/NOTE-microdata-rdf-20120308/</a></dd>
+    
+    
+    <dt>Editor:</dt>
+    <dd><a href="http://greggkellogg.net/">Gregg Kellogg</a>, Kellogg Associates</dd>
+
+    
+      <dt>Authors:</dt>
+      <dd><a href="mailto:[email protected]">Ian Hickson</a>, Google, Inc.</dd>
+<dd><a href="http://greggkellogg.net/">Gregg Kellogg</a>, Kellogg Associates</dd>
+<dd><a href="http://www.jenitennison.com/">Jeni Tennison</a>, Independent</dd>
+<dd><a href="http://www.w3.org/People/Ivan/">Ivan Herman</a>, <a href="http://www.w3.org"><abbr title="World Wide Web Consortium">W3C</abbr></a></dd>
+
+    
+  </dl>
+  
+  
+    <p>
+      
+        This document is also available in this non-normative format: 
+      
+      <a href="diff-20120308.html">diff to previous version</a>
+    </p>
+  
+  
+  
+    
+      <p class="copyright">
+        <a href="http://www.w3.org/Consortium/Legal/ipr-notice#Copyright">Copyright</a> © 
+        2011-2012
+        
+        <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>HTML microdata [<cite><a class="bibref" href="#bib-MICRODATA">MICRODATA</a></cite>] is an extension to HTML used to embed machine-readable data into HTML documents.
+    Whereas the microdata specification describes a means of markup, the output format is JSON. This specification
+    describes processing rules that may be used to extract RDF [<cite><a class="bibref" href="#bib-RDF-CONCEPTS">RDF-CONCEPTS</a></cite>] from an HTML document containing
+    microdata.</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 is an experimental work in progress. The concepts described herein are intended to 
+  provide guidance for a possible future Working Group chartered to provide a Recommendation
+  for this transformation. As a consequence, implementers of this specification, either producers
+  or consumers, should note that it may change prior to any possible publication as a Recommendation.</p>
+
+<p>This Working Draft is an update of the <a href="/TR/2012/NOTE-microdata-rdf-20120308/"><abbr title="World Wide Web Consortium">W3C</abbr>
+Interest Group Note</a>, published in March 2012. This update adds the 
+<a href="#vocab_expansion">Vocabulary Expansion</a> feature to the conversion algorithm, in response to the 
+evolution of vocabularies discussed on the <a href="/2001/sw/interest/webschema.html">Web Schemas Task Force</a> 
+of the <a href="/2001/sw/interest/">Semantic Web Interest Group</a> at <abbr title="World Wide Web Consortium">W3C</abbr>. The intention is to publish 
+this draft as a new version of the Interest Group Note after gathering and incorporating community input.
+</p> 
+
+        <p>
+          This document was published by the <a href="http://www.w3.org/2001/sw/interest/">Semantic Web Interest Group</a> as a Working Draft.
+          
+          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/semantic-web/">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>.
+          
+          The group does not expect this document to become a <abbr title="World Wide Web Consortium">W3C</abbr> Recommendation.
+          
+            
+              <abbr title="World Wide Web Consortium">W3C</abbr> maintains a <a href="" 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><ul class="toc"><li class="tocline"><a href="#background" class="tocxref"><span class="secno">1.1 </span>Background</a></li><li class="tocline"><a href="#use-cases" class="tocxref"><span class="secno">1.2 </span>Use Cases</a></li><li class="tocline"><a href="#issues" class="tocxref"><span class="secno">1.3 </span>Issues</a></li></ul></li><li class="tocline"><a href="#attributes-and-syntax" class="tocxref"><span class="secno">2. </span>Attributes and Syntax</a></li><li class="tocline"><a href="#vocabulary-registry" class="tocxref"><span class="secno">3. </span>Vocabulary Registry</a><ul class="toc"><li class="tocline"><a href="#property-uri-generation" class="tocxref"><span class="secno">3.1 </span>Property URI Generation</a></li><li class="tocline"><a href="#value-ordering" class="tocxref"><span class="secno">3.2 </span>Value Ordering</a></li><li class="tocline"><a href="#value-typing" class="tocxref"><span class="secno">3.3 </span>Value Typing</a></li></ul></li><li class="tocline"><a href="#vocabulary-expansion" class="tocxref"><span class="secno">4. </span>Vocabulary Expansion</a><ul class="toc"><li class="tocline"><a href="#vocabulary-entailment" class="tocxref"><span class="secno">4.1 </span>Vocabulary Entailment</a></li><li class="tocline"><a href="#vocabulary-expansion-control-of-microdata-processors" class="tocxref"><span class="secno">4.2 </span>Vocabulary Expansion Control of Microdata Processors</a></li></ul></li><li class="tocline"><a href="#algorithm" class="tocxref"><span class="secno">5. </span>Algorithm</a><ul class="toc"><li class="tocline"><a href="#algorithm-terms" class="tocxref"><span class="secno">5.1 </span>Algorithm Terms</a></li><li class="tocline"><a href="#rdf-conversion-algorithm" class="tocxref"><span class="secno">5.2 </span>RDF Conversion Algorithm</a></li><li class="tocline"><a href="#generate-the-triples" class="tocxref"><span class="secno">5.3 </span>Generate the triples</a></li><li class="tocline"><a href="#generate-predicate-uri" class="tocxref"><span class="secno">5.4 </span>Generate Predicate URI</a></li><li class="tocline"><a href="#generate-property-values" class="tocxref"><span class="secno">5.5 </span>Generate Property Values</a></li><li class="tocline"><a href="#generate-collection" class="tocxref"><span class="secno">5.6 </span>Generate RDF Collection</a></li></ul></li><li class="tocline"><a href="#testing" class="tocxref"><span class="secno">A. </span>Testing</a></li><li class="tocline"><a href="#markup-examples" class="tocxref"><span class="secno">B. </span>Markup Examples</a></li><li class="tocline"><a href="#example-registry" class="tocxref"><span class="secno">C. </span>Example <span class="formerLink">registry</span></a></li><li class="tocline"><a href="#acknowledgements" class="tocxref"><span class="secno">D. </span>Acknowledgements</a></li><li class="tocline"><a href="#references" class="tocxref"><span class="secno">E. </span>References</a><ul class="toc"><li class="tocline"><a href="#normative-references" class="tocxref"><span class="secno">E.1 </span>Normative references</a></li><li class="tocline"><a href="#informative-references" class="tocxref"><span class="secno">E.2 </span>Informative references</a></li></ul></li></ul></section>
+
+
+
+<section class="informative" id="introduction">
+  
+<!--OddPage-->
+<h2><span class="secno">1. </span>Introduction</h2><p><em>This section is non-normative.</em></p>
+  <p>This document describes a means of transforming HTML containing microdata into RDF. HTML Microdata [<cite><a class="bibref" href="#bib-MICRODATA">MICRODATA</a></cite>]
+    is an extension to HTML used to embed machine-readable data to HTML documents. This specification describes
+    transformation directly to RDF [<cite><a class="bibref" href="#bib-RDF-CONCEPTS">RDF-CONCEPTS</a></cite>].</p>
+  <div class="note"><div class="note-title"><span>Note</span></div><div class="">
+    <p>There are a variety of ways in which a mapping from microdata to
+      RDF might be configured to give a result that is closer to the required result for a particular vocabulary. This
+      specification defines terms that can be used as hooks for vocabulary-specific behavior, which could be defined
+      within a <a href="#dfn-registry" class="internalDFN">registry</a> or on an implementation-defined basis. However, the HTML Data TF recommends the
+      adoption of a single method of mapping in which every vocabulary is treated as if:</p>
+    <ul>
+      <li><a href="#dfn-propertyuri" class="internalDFN"><code>propertyURI</code></a> is set to <code>vocabulary</code> </li>
+      <li><a href="#dfn-multiplevalues" class="internalDFN"><code>multipleValues</code></a> is set to <code>unordered</code></li>
+    </ul>
+    <p>For background on the trade-offs between these options, see 
+      <a href="http://www.w3.org/wiki/Mapping_Microdata_to_RDF">http://www.w3.org/wiki/Mapping_Microdata_to_RDF</a>.</p>
+  </div></div>
+<section class="informative" id="background">
+  <h3><span class="secno">1.1 </span>Background</h3><p><em>This section is non-normative.</em></p>
+  <p>Microdata [<cite><a class="bibref" href="#bib-MICRODATA">MICRODATA</a></cite>] is a way of embedding data in HTML documents
+    using attributes. The HTML DOM is extended to provide an API for
+    accessing microdata information, and the microdata specification
+    defines how to generate a JSON representation from microdata markup.</p>
+
+  <p>Mapping microdata to RDF enables consumers to merge data expressed
+    in other RDF-based formats with microdata. It facilitates the use of
+    RDF vocabularies within microdata, and enables microdata to be used
+    with the full RDF toolchain. Some use cases for this mapping are
+    described in <a href="#use-cases">Section 1.2</a> below.</p>
+
+  <p>Microdata's data model does not align neatly with RDF.</p>
+  <ul>
+   <li>Non-URL microdata properties are disambiguated based on microdata
+     <a href="#dfn-item-type" class="internalDFN">item type</a>; an <a href="#dfn-item" class="internalDFN">item</a> with the type <code>http://example.org/Cat</code> can have
+     both the property <code>color</code> and the property <code>http://example.org/color</code>,
+     and these properties are semantically distinct under microdata. In
+     RDF, all properties have IRIs.</li>
+
+   <li>When an item has multiple properties with the same name, the values are
+     always ordered; in RDF, property values are unordered unless they
+     are explicitly listed in an <a href="#dfn-rdf-collection" class="internalDFN">RDF Collection</a>.</li>
+
+   <li>A value in microdata is always a simple string which is interpreted
+     by the consuming application. In RDF, values can be tagged with a
+     datatype or a language. According to the microdata specification, the
+     HTML context of microdata markup should not change how microdata is
+     interpreted, so although element names and HTML <code>@lang</code> attributes could
+     be used to provide datatype and language information for RDF data, this
+     would be contrary to the microdata specification.</li>
+  </ul>
+
+   <p>Thus, in some places the needs of RDF consumers violate requirements of
+     the microdata specification. This specification highlights where such
+     violations occur and the reasons for them.</p>
+
+   <p>This specification allows for 
+     <a href="#dfn-vocabulary" class="internalDFN">vocabulary</a>-specific rules that affect the generation of property URIs and value serializations.
+     This is facilitated by a <a href="#dfn-registry" class="internalDFN">registry</a> that associates URIs with specific rules based on matching
+     <a class="aref internalDFN" href="#dfn-itemtype">itemtype</a> values against registered URI prefixes do determine a vocabulary and potentially
+     vocabulary-specific processing rules.</p>
+
+   <p>This specification also assumes that consumers of RDF generated from
+     microdata may have to process the results in order to, for example,
+     assign appropriate datatypes to <a href="#dfn-property-value" class="internalDFN">property value</a>s.</p>
+</section>
+
+<section class="informative" id="use-cases">
+  <h3><span class="secno">1.2 </span>Use Cases</h3><p><em>This section is non-normative.</em></p>
+  <p>During the period of the task force, a number of use cases were put forth for the use of microdata
+    in generating RDF:</p>
+  <ul>
+    <li>Semantic search engines such as <a href="http://sindice.com/">Sindice</a> use RDF as their backend data model.
+      They want to gather information expressed using microdata alongside information expressed in RDF-based formats
+      and make it available to others to use, as a service. In these cases, the ultimate consumer, who will need to
+      understand the vocabularies used within the microdata, is the program or person who pulls out data from Sindice.
+      Sindice needs to retain the distinctions in the original microdata (e.g. ordering of items) and might not have
+      built-in knowledge about the <a href="#dfn-vocabulary" class="internalDFN">vocabulary</a> of interest to the ultimate consumer. In this case, the ultimate consumer
+      is likely to have to map/validate/handle errors in the data they get from Sindice.</li>
+    <li>A consumer such as <a href="http://openelectiondata.org">openelectiondata.org</a> wants to support
+      microdata-based markup of their <a href="#dfn-vocabulary" class="internalDFN">vocabulary</a> as well as RDFa-based markup, both going into an RDF-based data store.
+      They want to use an off-the-shelf tool to extract the microdata. They want to configure the tool to give them the
+      RDF that is appropriate for their known <a href="#dfn-vocabulary" class="internalDFN">vocabulary</a>.</li>
+    <li>A browser plugin that captures data for the user uses an RDF model as its backend store.
+      Any time it encounters microdata on a page, it wants to pull that microdata into the store on the fly.</li>
+    <li><a href="http://purl.org/goodrelations/">GoodRelations</a> properties do not take
+      <a title="rdf collection">rdf:List</a> values; when they take
+      multiple values they are unordered. The <code>rdfs:range</code> of a GoodRelations
+      property indicates the datatype of the expected value, and GoodRelations
+      processors will expect values to be cast to that type. Language
+      information from the HTML needs to be captured as it is common that
+      multiple values will be used to specify the same information in different
+      languages.</li>
+    <li><a href="http://schema.org/">Schema.org</a> has an 
+      <a href="http://schema.org/docs/extension.html">extension mechanism</a> to allow authors to express information
+      that is more detail than the pre-defined types, properties and enumerations. Property URIs are all in the same
+      flat-namespace as types, but authors can add more detail by using a '/' after the type or property to provide
+      more detail. For example, schema.org defines a <em>musicGroupMember</em> property having a URI of
+      <code>http://schema.org/musicGroupMember</code>, and an author might express more detail through an ad-hoc
+      sub-property <em>musicGroupMember/leadVocalist</em>, having the URI
+      <code>http://schema.org/musicGroupMember/leadVocalist</code>.</li>
+  </ul>
+</section>
+
+<section class="informative" id="issues">
+  <h3><span class="secno">1.3 </span>Issues</h3><p><em>This section is non-normative.</em></p>
+  <p>Decisions or open issues in the specification are tracked on the
+    <a href="http://www.w3.org/2011/htmldata/track/issues">Task Force Issue Tracker</a>. These include the
+    following:</p>
+  <div class="issue"><div class="issue-title"><a href="http://www.w3.org/2011/htmldata/track/issues/1"><span>Issue 1</span></a></div><p class="">Vocabulary specific parsing for Microdata.
+    This specification attempts to create generic
+    rules for processing microdata with typical RDF vocabularies.
+    A <a href="#dfn-registry" class="internalDFN">registry</a> allows
+    for exceptions to the default processing rules for certain well-known vocabularies.</p></div>
+  <div class="issue"><div class="issue-title"><a href="http://www.w3.org/2011/htmldata/track/issues/2"><span>Issue 2</span></a></div><p class="">Should Microdata-RDF generate XMLLiteral values.
+    This issue has been closed with no change
+    as this would violate microdata's data model.</p></div>
+  <div class="issue"><div class="issue-title"><a href="http://www.w3.org/2011/htmldata/track/issues/3"><span>Issue 3</span></a></div><p class="">Should the <a href="#dfn-registry" class="internalDFN">registry</a> allow property datatype specification.
+    The consensus is that datatypes are only derived from HTML semantics, so that only &lt;time&gt; values have a datatype other than plain.</p></div>
+  <div class="issue"><div class="issue-title"><a href="http://www.w3.org/2011/htmldata/track/issues/4"><span>Issue 4</span></a></div><p class="">Should the <a href="#dfn-registry" class="internalDFN">registry</a> allow a <a href="#dfn-name" class="internalDFN">name</a> or URL
+    to be used as an alias for <a class="aref internalDFN" href="#dfn-itemid">itemid</a>.</p></div>
+
+  <p>The purpose of this specification is to provide input to a future working group that can make decisions
+    about the need for a <a href="#dfn-registry" class="internalDFN">registry</a> and the details of processing. Among the options investigated by
+    the Task Force are the following:</p>
+  <ul>
+    <li>Property URI generation using the original microdata specification with a base URI and
+      <cite><a href="http://tools.ietf.org/html/rfc3986#section-3.5">fragment</a></cite> made up of the in-scope <a href="#dfn-item-type" class="internalDFN">item
+      type</a> and <a href="#dfn-properties" class="internalDFN">properties</a>.</li>
+    <li>Vocabulary-based URI generation, where the <a href="#dfn-vocabulary" class="internalDFN">vocabulary</a> is determined from the
+      in-scope <a href="#dfn-item-type" class="internalDFN">item type</a>, either through an algorithmic modification of the type URL or by matching the
+      URL against a <a href="#dfn-registry" class="internalDFN">registry</a>. The vocabulary URI is then used to generate property URIs in a namespace
+      parallel to the type URI.</li>
+    <li>When there are multiple <a href="#dfn-top-level-item" class="internalDFN">top-level item</a>s in a document, place items in an RDF Collection.
+      Alternatively, simply list the items as multiple values, or do not generate an
+      <code>http://www.w3.org/ns/md#item</code> mapping at all.</li>
+    <li>When an item has multiple values for a given <a href="#dfn-property" class="internalDFN">property</a>, place the values in an RDF Collection.
+      Alternatively, do not use collections, use an alternative such as <code>rdf:Seq</code>, or place all values,
+      whether or not multiple, into some form of collection.</li>
+  </ul>
+  <p>More examples and explanatory information are available in [<cite><a class="bibref" href="#bib-MICRODATA-RDF-SUPPLEMENT">MICRODATA-RDF-SUPPLEMENT</a></cite>], which may
+    be updated from time to time.</p>
+</section>
+</section>
+
+<section id="attributes-and-syntax">
+  
+<!--OddPage-->
+<h2><span class="secno">2. </span>Attributes and Syntax</h2>
+  <p>
+    The microdata specification [<cite><a class="bibref" href="#bib-MICRODATA">MICRODATA</a></cite>] defines a number of attributes and the way in which those
+    attributes are to be interpreted. The
+    <cite><a href="http://www.w3.org/TR/2011/WD-microdata-20110525/#microdata-dom-api">microdata DOM API</a></cite>
+    provides methods and attributes for retrieving microdata from the HTML DOM.</p>
+  <p>For reference, attributes used for specifying and retrieving HTML microdata are referenced here:</p>
+  <dl>
+    <dt><dfn class="adef" id="dfn-itemid">itemid</dfn></dt><dd>
+      An attribute containing a URL used to identify the subject of triples associated with this <a href="#dfn-item" class="internalDFN">item</a>.
+      (See <cite><a href="http://www.w3.org/TR/2011/WD-microdata-20110525/#attr-itemid">Items</a></cite>
+      in [<cite><a class="bibref" href="#bib-MICRODATA">MICRODATA</a></cite>]).
+    </dd>
+    <dt><dfn class="adef" id="dfn-itemprop">itemprop</dfn></dt><dd>
+      An attribute used to identify one or more <a href="#dfn-name" class="internalDFN">name</a>s of an <a href="#dfn-item" class="internalDFN">item</a>s. An <a class="aref internalDFN" href="#dfn-itemprop">itemprop</a>
+      contains a space separated list of <dfn id="dfn-name">name</dfn>s which may either by <a href="#dfn-absolute-url" class="internalDFN">absolute URL</a>s or terms
+      associated with the type of the <a href="#dfn-item" class="internalDFN">item</a> as defined by the referencing <a href="#dfn-item" class="internalDFN">item</a>'s
+      <a href="#dfn-item-type" class="internalDFN">item type</a>.
+      (See <cite><a href="http://www.w3.org/TR/2011/WD-microdata-20110525/#names:-the-itemprop-attribute">Items</a></cite>
+      in [<cite><a class="bibref" href="#bib-MICRODATA">MICRODATA</a></cite>]).
+    </dd>
+    <dt><dfn class="adef" id="dfn-itemref">itemref</dfn></dt><dd>
+      An additional attribute on an element that references additional elements containing property
+      definitions to be applied to the referencing <a href="#dfn-item" class="internalDFN">item</a>.
+      (See <cite><a href="http://www.w3.org/TR/2011/WD-microdata-20110525/#attr-itemref">Items</a></cite>
+      in [<cite><a class="bibref" href="#bib-MICRODATA">MICRODATA</a></cite>]).
+    </dd>
+    <dt><dfn class="adef" id="dfn-itemscope">itemscope</dfn></dt><dd>
+      An boolean attribute identifying an element as an <a href="#dfn-item" class="internalDFN">item</a>.
+      (See <cite><a href="http://www.w3.org/TR/2011/WD-microdata-20110525/#attr-itemscope">Items</a></cite>
+      in [<cite><a class="bibref" href="#bib-MICRODATA">MICRODATA</a></cite>]).
+    </dd>
+    <dt><dfn class="adef" id="dfn-itemtype">itemtype</dfn></dt><dd>
+      An additional attribute on an element used to specify one or more types of an <a href="#dfn-item" class="internalDFN">item</a>.
+      The <dfn id="dfn-item-type">item type</dfn> of an <a href="#dfn-item" class="internalDFN">item</a> is the first value returned from
+      <code><cite><a href="http://www.w3.org/TR/2011/WD-microdata-20110525/#dom-itemtype">element.itemType</a></cite></code>
+      on the element.
+      The <a href="#dfn-item-type" class="internalDFN">item type</a> is also used to resolve non-URL <a href="#dfn-name" class="internalDFN">name</a>s to <a href="#dfn-absolute-url" class="internalDFN">absolute URL</a>s.
+      Available through the
+      <cite><a href="http://www.w3.org/TR/2011/WD-microdata-20110525/#microdata-dom-api">Microdata DOM API</a></cite> as
+      <code><cite><a href="http://www.w3.org/TR/2011/WD-microdata-20110525/#dom-itemtype">element.itemType</a></cite></code>.
+      (See <cite><a href="http://www.w3.org/TR/2011/WD-microdata-20110525/#attr-itemtype">Items</a></cite>
+      in [<cite><a class="bibref" href="#bib-MICRODATA">MICRODATA</a></cite>]).
+    </dd>
+  </dl>
+  <p>In RDF, it is common for people to shorten vocabulary terms via abbreviated URIs that use a 'prefix'
+    and a 'reference'. throughout this document assume that the following vocabulary
+    prefixes have been defined:</p>
+  <table><tbody>
+    <tr>
+      <td>dc:</td>
+      <td>http://purl.org/dc/terms/</td>
+    </tr>
+
+    <tr>
+      <td>md:</td>
+      <td>
+        http://www.w3.org/ns/md#</td>
+    </tr>
+
+    <tr>
+      <td>rdf:</td>
+      <td>
+        http://www.w3.org/1999/02/22-rdf-syntax-ns#</td>
+    </tr>
+
+    <tr>
+      <td>rdf:</td>
+      <td>
+        http://www.w3.org/1999/02/22-rdf-syntax-ns#</td>
+    </tr>
+
+    <tr>
+      <td>rdfa:</td>
+      <td>
+        http://www.w3.org/ns/rdfa#</td>
+    </tr>
+
+    <tr>
+      <td>xsd:</td>
+      <td>http://www.w3.org/2001/XMLSchema#</td>
+    </tr>
+  </tbody></table>
+</section>
+
+<section class="informative" id="vocabulary-registry">
+  
+<!--OddPage-->
+<h2><span class="secno">3. </span>Vocabulary Registry</h2><p><em>This section is non-normative.</em></p>
+  <p>In a perfect world, all processors would be able to generate the same output for a given input
+    without regards to the requirements of a particular <a href="#dfn-vocabulary" class="internalDFN">vocabulary</a>. However, microdata doesn't
+    provide sufficient syntactic help in making these decisions. Different vocabularies have different
+    needs.</p>
+  <p>The registry is located at the namespace defined for microdata: <code>http://www.w3.org/ns/md</code> in
+    a variety of formats.</p>
+  <p>The <dfn id="dfn-registry">registry</dfn> associates a <dfn id="dfn-uri-prefix">URI prefix</dfn> with one or more key-value pairs denoting
+  processor behavior. A hypothetical JSON representation of such a registry might be the following:</p>
+<div class="example"><div class="example-title"><span>Example 1</span></div><pre class="example">{
+  &quot;http://schema.org/&quot;: {
+    &quot;propertyURI&quot;:    &quot;vocabulary&quot;,
+    &quot;multipleValues&quot;: &quot;unordered&quot;,
+    &quot;properties&quot;: {
+      &quot;tracks&quot;: {&quot;multipleValues&quot;: &quot;list&quot;}
+    }
+  },
+  &quot;http://microformats.org/profile/hcard&quot;: {
+    &quot;propertyURI&quot;:    &quot;vocabulary&quot;,
+    &quot;multipleValues&quot;: &quot;list&quot;,
+    &quot;properties&quot; {
+      &quot;url&quot;: {&quot;multipleValues&quot;: &quot;unordered&quot;}
+    }
+  }
+}</pre></div>
+  <p>This structure associates mappings for two URIs, <code>http://schema.org/</code> and
+    <code>http://microformats.org/profile/hcard</code>. Items having an <a href="#dfn-item-type" class="internalDFN">item type</a> with a <a href="#dfn-uri-prefix" class="internalDFN">URI
+    prefix</a> from this <a href="#dfn-registry" class="internalDFN">registry</a> use the the rules described for that prefix within the scope of that
+    <a href="#dfn-item-type" class="internalDFN">item type</a>. This mapping currently defines two rules: <a href="#dfn-propertyuri" class="internalDFN"><code>propertyURI</code></a> and
+    <a href="#dfn-multiplevalues" class="internalDFN"><code>multipleValues</code></a> with values to indicate specific behavior. It also allows overrides
+    on a per-property basis; the <a href="#dfn-properties" class="internalDFN"><code>properties</code></a> key associates an individual <a href="#dfn-name" class="internalDFN">name</a>
+    with overrides for default behavior.
+    The interpretation of these
+    rules is defined in the following sections. If an item has no <a href="#dfn-current-type" class="internalDFN">current type</a> or the
+    <a href="#dfn-registry" class="internalDFN">registry</a> contains no <a href="#dfn-uri-prefix" class="internalDFN">URI prefix</a> matching <a href="#dfn-current-type" class="internalDFN">current type</a>, a conforming
+    processor <em class="rfc2119" title="must">must</em> use the default values defined for these rules.</p>
+  <div class="note"><div class="note-title"><span>Note</span></div><p class="">The concept of a <a href="#dfn-registry" class="internalDFN">registry</a>, including a hypothetical format, location and updating rules
+    is presented as an abstract concept useful for describing the function of a microdata processor.
+    There are issues surrounding update
+    frequency, URL naming, and how updates are authorized. This spec
+    just considers the semantic content of such a <a href="#dfn-registry" class="internalDFN">registry</a> and how it can be used to affect processing without
+    defining its representation or update policies.</p></div>
+
+<section class="informative" id="property-uri-generation">
+  <h3><span class="secno">3.1 </span>Property URI Generation</h3><p><em>This section is non-normative.</em></p>
+  <p>For <a href="#dfn-name" class="internalDFN">name</a>s which are not <a href="#dfn-absolute-url" class="internalDFN">absolute URL</a>s,
+    the <dfn id="dfn-propertyuri"><code>propertyURI</code></dfn> rule defines the algorithm for generating an <a href="#dfn-absolute-url" class="internalDFN">absolute URL</a>
+    given an <a href="#dfn-evaluation-context" class="internalDFN">evaluation context</a> including a <a href="#dfn-current-type" class="internalDFN">current type</a>, <a href="#dfn-current-name" class="internalDFN">current name</a> and
+    <a href="#dfn-current-vocabulary" class="internalDFN">current vocabulary</a>.</p>
+  <p>The procedure for generating property URIs is defined in
+    <a href="#generate-predicate-uri">Generate Predicate URI</a>.</p>
+  <p>Possible values for <a href="#dfn-propertyuri" class="internalDFN"><code>propertyURI</code></a> are the following:</p>
+  <dl>
+    <dt><code>contextual</code></dt><dd>
+      The <code>contextual</code> URI generation scheme guarantees that generated property URIs are
+      unique based on the value of <a href="#dfn-current-name" class="internalDFN">current name</a>. This is
+      required as the microdata data model requires that <a href="#dfn-name" class="internalDFN">name</a>s are associated with specific
+      items and do not have a global scope. (See <a href="#scheme-context">Step 5</a> in
+      <a href="#generate-predicate-uri">Generate Predicate URI</a>).
+      <div>
+        <p>URI creation uses a base URI with query parameters to indicate the in-scope
+          type and <a href="#dfn-name" class="internalDFN">name</a> list. Consider the following example:</p>
+        <div class="example"><div class="example-title"><span>Example 2</span></div><pre class="example">&lt;span itemscope itemtype=&quot;http://microformats.org/profile/hcard&quot;&gt;
+  &lt;span itemprop=&quot;n&quot; itemscope&gt;
+    &lt;span itemprop=&quot;given-name&quot;&gt;
+      Princeton
+    &lt;/span&gt;
+  &lt;/span&gt;
+&lt;/span&gt;</pre></div>
+        <p>The first <a href="#dfn-name" class="internalDFN">name</a> <em>n</em> generates the URI
+          <code>http://www.w3.org/ns/md?type=http://microformats.org/profile/hcard?prop=n</code>.
+          However, the included <a href="#dfn-name" class="internalDFN">name</a> <em>given-name</em> is included in untyped item.
+          The inherited property URI is used to create a new property URI:
+          <code>http://www.w3.org/ns/md?type=http://microformats.org/profile/hcard?prop=n.given-name</code>.</p>
+        <p>This scheme is compatible with the needs of other RDF serialization formats such as
+          RDF/XML [<cite><a class="bibref" href="#bib-RDF-SYNTAX-GRAMMAR">RDF-SYNTAX-GRAMMAR</a></cite>],
+          which rely on <em>QNames</em> for expressing properties. For example, the generated property URIs
+          can be split as follows:</p>
+        <div class="example"><div class="example-title"><span>Example 3</span></div><pre class="example">&lt;rdf:Description xmlns:hcard=&quot;http://www.w3.org/ns/md?type=http://microformats.org/profile/hcard?prop=&quot;
+                 rdf:type=&quot;http://microformats.org/profile/hcard&quot;&gt;
+  &lt;hcard:n&gt;
+    &lt;rdf:Description&gt;
+      &lt;hcard:n.given-name&gt;
+        Princeton
+      &lt;/hcard:n.given-name&gt;
+    &lt;/rdf:Description&gt;
+  &lt;/hcard:n&gt;
+&lt;/rdf:Description&gt;</pre></div>
+        <p>Looking at another example:</p>
+        <div class="example"><div class="example-title"><span>Example 4</span></div><pre class="example">&lt;div itemscope itemtype=&quot;http://schema.org/Person&quot;&gt;
+  &lt;h2 itemprop=&quot;name&quot;&gt;Jeni&lt;/h2&gt;
+&lt;/div&gt;</pre></div>
+        <p>This would generate <code>http://www.w3.org/ns/md?type=http://schema.org/Person&amp;prop=name</code>.</p>
+      </div>
+    </dd>
+    <dt><code>vocabulary</code></dt><dd>
+      The <code>vocabulary</code> URI generation scheme appends <a href="#dfn-name" class="internalDFN">name</a>s that are not
+      <a href="#dfn-absolute-url" class="internalDFN">absolute URL</a>s to the <a href="#dfn-uri-prefix" class="internalDFN">URI prefix</a>. When generating property URIs, if the <a href="#dfn-uri-prefix" class="internalDFN">URI prefix</a>
+      does not end with a '/' or '#', a '#' is appended to the <a href="#dfn-uri-prefix" class="internalDFN">URI prefix</a>. (See <a href="#scheme-vocab">Step 4</a>
+      in
+      <a href="#generate-predicate-uri">Generate Predicate URI</a>.)
+      <div>
+        <p>URI creation uses a base URL with query parameters to indicate the in-scope
+          type and <a href="#dfn-name" class="internalDFN">name</a> list. Consider the following example:</p>
+        <div class="example"><div class="example-title"><span>Example 5</span></div><pre class="example">&lt;span itemscope itemtype=&quot;http://microformats.org/profile/hcard&quot;&gt;
+  &lt;span itemprop=&quot;n&quot; itemscope&gt;
+    &lt;span itemprop=&quot;given-name&quot;&gt;
+      Princeton
+    &lt;/span&gt;
+  &lt;/span&gt;
+&lt;/span&gt;</pre></div>
+        <p>Given the <a href="#dfn-uri-prefix" class="internalDFN">URI prefix</a> <code>http://microformats.org/profile/hcard</code>, this
+          would generate <code>http://microformats.org/profile/hcard#n</code> and
+          <code>http://microformats.org/profile/hcard#given-name</code>. Note that the '#' is automatically
+          added as a separator.</p>
+        <p>Looking at another example:</p>
+        <div class="example"><div class="example-title"><span>Example 6</span></div><pre class="example">&lt;div itemscope itemtype=&quot;http://schema.org/Person&quot;&gt;
+  &lt;h2 itemprop=&quot;name&quot;&gt;Jeni&lt;/h2&gt;
+&lt;/div&gt;</pre></div>
+        <p>Given the <a href="#dfn-uri-prefix" class="internalDFN">URI prefix</a> <code>http://schema.org/</code>,
+          this would generate <code>http://schema.org/name</code>. Note that if the <a class="aref internalDFN" href="#dfn-itemtype">itemtype</a>
+          were <code>http://schema.org/Person/Teacher</code>, this would generate the same property URI.</p>
+      </div>
+    </dd>
+  </dl>
+  <p>If the <a href="#dfn-registry" class="internalDFN">registry</a> contains no match for <a href="#dfn-current-type" class="internalDFN">current type</a> implementations act as if
+    there is a <a href="#dfn-uri-prefix" class="internalDFN">URI prefix</a> made from the first <a class="aref internalDFN" href="#dfn-itemtype">itemtype</a> value by stripping either the <cite><a href="http://tools.ietf.org/html/rfc3986#section-3.5">fragment</a></cite> content or <cite><a href="http://tools.ietf.org/html/rfc3986#section-3.3">last path segment</a></cite>, if the value has no fragment (See
+    [<cite><a class="bibref" href="#bib-RFC3986">RFC3986</a></cite>]).</p>
+  <div class="note"><div class="note-title"><span>Note</span></div><p class="">Deconstructing the <a class="aref internalDFN" href="#dfn-itemtype">itemtype</a> URL to create or identify a vocabulary URI
+    is a violation of the microdata specification which is necessary to
+    support the use of existing vocabularies designed for use with RDF, and
+    shared or inherited properties within all vocabularies.</p></div>
+  <p>The default value of <a href="#dfn-propertyuri" class="internalDFN"><code>propertyURI</code></a> is <code>vocabulary</code>.</p>
+  <div class="example"><div class="example-title"><span>Example 7</span></div><pre class="example">&lt;div itemscope itemtype=&quot;http://schema.org/Book&quot;&gt;
+  &lt;h2 itemprop=&quot;title&quot;&gt;Just a Geek&lt;/h2&gt;
+&lt;/div&gt;</pre></div>
+  <p>In this example, assuming no matching entry in the <a href="#dfn-registry" class="internalDFN">registry</a>,
+    the <a href="#dfn-uri-prefix" class="internalDFN">URI prefix</a> is constructed by removing the
+    <cite><a href="http://tools.ietf.org/html/rfc3986#section-3.3">last path segment</a></cite>, leaving the URI
+    <code>http://schema.org/</code>. As there is no explicit <a href="#dfn-propertyuri" class="internalDFN"><code>propertyURI</code></a>,
+    the default <code>vocabulary</code> is used, and the resulting property URI would be
+    <code>http://schema.org/title</code>.</p>
+</section>
+
+<section class="informative" id="value-ordering">
+  <h3><span class="secno">3.2 </span>Value Ordering</h3><p><em>This section is non-normative.</em></p>
+  <p>For items having multiple values for a given <a href="#dfn-property" class="internalDFN">property</a>,
+    the <dfn id="dfn-multiplevalues"><code>multipleValues</code></dfn> rule defines the algorithm for serializing these values.
+    Microdata uses document order when generating <a href="#dfn-property-value" class="internalDFN">property value</a>s, as defined in
+    <cite><a href="http://www.w3.org/TR/2011/WD-microdata-20110525/#microdata-dom-api">Microdata DOM API</a></cite>
+    as <code>element.itemValue</code>. However, many RDF vocabularies expect multiple values to be generated
+    as triples sharing a common subject and predicate. In some cases, it may be useful to retain value ordering.</p>
+  <p>The procedure for generating <a href="#dfn-property-value" class="internalDFN">property value</a>s is defined in
+    <a href="#generate-property-values">Generate Property Values</a>.</p>
+  <p>Possible values for <a href="#dfn-multiplevalues" class="internalDFN"><code>multipleValues</code></a> are the following:</p>
+  <dl>
+    <dt><code>unordered</code></dt><dd>
+      Values are serialized without ordering using a common subject and predicate.
+      (See <a href="#values-unordered">Step 7</a> in
+      <a href="#generate-property-values">Generate Property Values</a>).
+    </dd>
+    <dt><code>list</code></dt><dd>
+      Multi-valued <a class="aref internalDFN" href="#dfn-itemprop">itemprop</a>s are serialized using an <a href="#dfn-rdf-collection" class="internalDFN">RDF Collection</a>.
+      (See <a href="#values-list">Step 8</a> in
+      <a href="#generate-property-values">Generate Property Values</a>).
+    </dd>
+  </dl>
+  <p>An example of how this might be specified in a <a href="#dfn-registry" class="internalDFN">registry</a> is the following:</p>
+  <div class="example"><div class="example-title"><span>Example 8</span></div><pre class="example">{
+  &quot;http://schema.org/&quot;: {
+    &quot;propertyURI&quot;:    &quot;vocabulary&quot;,
+    <span class="diff">&quot;multipleValues&quot;: &quot;unordered&quot;</span>
+  },
+  &quot;http://microformats.org/profile/hcard&quot;: {
+    &quot;propertyURI&quot;:    &quot;vocabulary&quot;,
+    <span class="diff">&quot;multipleValues&quot;: {&quot;multipleValues&quot;: &quot;list&quot;}</span>
+  }
+}</pre></div>
+  <p>Additionally, some vocabularies may wish to specify this on a per-property basis. For example,
+    within <code>http://schema.org/MusicPlaylist</code> the <code>tracks</code> property might depend on the order
+    of values to to reproduce associated <code>MusicRecording</code> values.</p>
+  <div class="example"><div class="example-title"><span>Example 9</span></div><pre class="example">{
+ &quot;http://schema.org/&quot;: {
+   &quot;propertyURI&quot;: &quot;vocabulary&quot;,
+   &quot;multipleValues&quot;: &quot;unordered&quot;<span class="diff">,
+   &quot;properties&quot;: {
+     &quot;tracks&quot;: {&quot;multipleValues&quot;: &quot;list&quot;}
+   }</span>
+ }
+}</pre></div>
+  <p>The <dfn id="dfn-properties"><code>properties</code></dfn> key takes a JSON Object as a value, which in turn has keys for each
+    property that is to be given alternate semantics. Each <a href="#dfn-name" class="internalDFN">name</a> is implicitly expanded to it's URI
+    representation as defined in <a href="#generate-predicate-uri">Generate Predicate URI</a>, so that
+    the behavior is the same whether or not the <a href="#dfn-name" class="internalDFN">name</a> is listed as an <a href="#dfn-absolute-url" class="internalDFN">absolute URL</a>.</p>
+  <p>The default value of <a href="#dfn-multiplevalues" class="internalDFN"><code>multipleValues</code></a> is <code>unordered</code>.</p>
+  <div class="note"><div class="note-title"><span>Note</span></div><div class="">
+    <p>An alternative mechanism would output <em>both</em> unordered and ordered values, to allow an application
+    to choose the most useful representation. For example, consider the following:</p>
+<div class="example"><div class="example-title"><span>Example 10</span></div><pre class="example">&lt;div itemscope itemtype=&quot;http://schema.org/MusicPlaylist&quot;&gt;
+  &lt;span itemprop=&quot;name&quot;&gt;Classic Rock Playlist&lt;/span&gt;
+  &lt;meta itemprop=&quot;numTracks&quot; content=&quot;2&quot;/&gt;
+  &lt;p&gt;Including works by
+    &lt;span itemprop=&quot;byArtist&quot;&gt;Lynard Skynard&lt;/span&gt; and
+    &lt;span itemprop=&quot;byArtist&quot;&gt;AC/DC&lt;/span&gt;&lt;/p&gt;.
+
+  &lt;div itemprop=&quot;tracks&quot; itemscope itemtype=&quot;http://schema.org/MusicRecording&quot;&gt;
+    1.&lt;span itemprop=&quot;name&quot;&gt;Sweet Home Alabama&lt;/span&gt; -
+    &lt;span itemprop=&quot;byArtist&quot;&gt;Lynard Skynard&lt;/span&gt;
+    &lt;link href=&quot;sweet-home-alabama&quot; itemprop=&quot;url&quot; /&gt;
+   &lt;/div&gt;
+
+  &lt;div itemprop=&quot;tracks&quot; itemscope itemtype=&quot;http://schema.org/MusicRecording&quot;&gt;
+    2.&lt;span itemprop=&quot;name&quot;&gt;Shook you all Night Long&lt;/span&gt; -
+    &lt;span itemprop=&quot;byArtist&quot;&gt;AC/DC&lt;/span&gt;
+    &lt;link href=&quot;shook-you-all-night-long&quot; itemprop=&quot;url&quot; /&gt;
+  &lt;/div&gt;
+&lt;/div&gt;</pre></div>
+    <p>This might generate the following Turtle:</p>
+<div class="example"><div class="example-title"><span>Example 11</span></div><pre class="example">@prefix md: &lt;http://www.w3.org/ns/md#&gt; .
[email protected] rdf: &lt;http://www.w3.org/1999/02/22-rdf-syntax-ns#&gt; .
[email protected] rdfa: &lt;http://www.w3.org/ns/rdfa#&gt; .
[email protected] schema: &lt;http://schema.org/&gt; .
+
+&lt;&gt; md:item [
+  a schema:MusicPlaylist;
+    schema:name &quot;Classic Rock Playlist&quot;;
+    schema:byArtist (&quot;Lynard Skynard&quot; &quot;AC/DC&quot;);
+    schema:numTracks &quot;2&quot;;
+    schema:tracks _:track1, _:track2, (_:track1 _:track2)
+  ];
+  rdfa:usesVocabulary schema:
+ .
+_:track1 a schema:MusicRecording;
+  schema:byArtist (&quot;Lynard Skynard&quot;);
+  schema:name &quot;Sweet Home Alabama&quot;;
+  schema:url &lt;sweet-home-alabama&gt; .
+_:track2 a schema:MusicRecording;
+  schema:byArtist (&quot;AC/DC&quot;);
+  schema:name &quot;Shook you all Night Long&quot;;
+  schema:url &lt;shook-you-all-night-long&gt; .</pre></div>
+    <p>By providing both <code>_:track1</code> and <code>_:track2</code> as object values of the playlist
+      along with an RDF Collection containing the ordered values, the data may be queried via a simple
+      query using the playlist subject, or as an ordered collection.</p>
+  </div></div>
+</section>
+
+<section class="informative" id="value-typing">
+  <h3><span class="secno">3.3 </span>Value Typing</h3><p><em>This section is non-normative.</em></p>
+  <p>In microdata, all values are strings. In RDF, values may be resources
+   or may be typed with an appropriate datatype.</p>
+  <p> In some cases, the type of a microdata value can be determined from the
+   element on which it is specified. In particular:</p>
+  <ul>
+    <li>URL property elements provide URLs</li>
+    <li><code>time</code> element provides dates and times</li>
+  </ul>
+  <div class="issue"><div class="issue-title"><span>Issue</span></div><p class="">Using information about the content of the document where the microdata
+   is marked up <em>might</em> be a violation of the spirit of the microdata specification, though it does not explicitly say in
+   normative text that consumers cannot use other information from the HTML DOM to interpret microdata.</p></div>
+
+  <p>Additionally, one possible use of a <a href="#dfn-registry" class="internalDFN">registry</a> would allow vocabularies to be marked with datatype information,
+    so that a <code>dc:time</code> value, for example, would be understood to represent a literal with datatype
+    <code>xsd:date</code>. This could be done by adding information for each property in the vocabulary requiring
+    special treatment.</p>
+  <p>This might be represented using a syntax such as the following:</p>
+  <div class="example"><div class="example-title"><span>Example 12</span></div><pre class="example">{
+ &quot;http://schema.org/&quot;: {
+   &quot;propertyURI&quot;: &quot;vocabulary&quot;,
+   &quot;multipleValues&quot;: &quot;unordered&quot;<span class="diff">,
+   &quot;properties&quot;: {
+     &quot;dateCreated&quot;: {&quot;datatype&quot;: &quot;http://www.w3.org/2001/XMLSchema#date&quot;}
+   }</span>
+ }
+}</pre></div>
+  <p>The <code>datatype</code> identifies a URI to be used in constructing a <a href="#dfn-typed-literal" class="internalDFN">typed literal</a>.</p>
+
+  <p>In most cases, the relevant datatype for a value can be derived from
+    knowledge of what property the value is for and the syntax of the value
+    itself. Thus, values can be given datatypes in a post-processing step
+    after the mapping of microdata to RDF described by this specification.
+    However, where there is information in the HTML markup, such as knowledge
+    of what element was used to mark up the value, which can help with
+    determining its datatype, that information is used by this specification.</p>
+  <p>This concept is not explored further at this time, but could be developed further in
+    a future revision of this document.</p>
+
+  <div class="note"><div class="note-title"><span>Note</span></div><p class="">If property URI generation was fixed to <code>vocabulary</code>, multiple values always
+    generated both <code>unordered</code> and <code>ordered</code> representations, and there were <code>datatype</code>
+    support, the <a href="#dfn-registry" class="internalDFN">registry</a> could be reduced to a simple list of URLs without any further structure necessary.</p></div>
+</section>
+</section>
+
+<section id="vocabulary-expansion">
+  
+<!--OddPage-->
+<h2 id="vocab_expansion"><span class="secno">4. </span>Vocabulary Expansion</h2>
+  <p>Microdata requires that all values of <a class="aref internalDFN" href="#dfn-itemtype">itemtype</a> come from the same vocabulary. This
+    is required as <a class="aref internalDFN" href="#dfn-itemprop">itemprop</a> values are resolved relative to that vocabulary. However,
+    it is often useful to define an <a href="#dfn-item" class="internalDFN">item</a> to have types from multiple different vocabularies.</p>
+  <p>Vocabulary expansion uses simple rules to generate additional triples based on 
+    rules and property relationships described in the <a href="#dfn-registry" class="internalDFN">registry</a>.
+    Within the <a href="#dfn-registry" class="internalDFN">registry</a>, a property definition may have either <code>equivalentProperty</code>
+    or <code>subPropertyOf</code> keys having a IRI value (or array of IRI values)
+    of the associated property. Such an
+    entry causes the processor to generate triples associating the source
+    property IRI with the target property IRI using either
+    <code>http://www.w3.org/2000/01/rdf-schema#subPropertyOf</code> or
+    <code>http://www.w3.org/2002/07/owl#equivalentProperty</code> predicates.</p>
+   <p>For example, the <a href="#dfn-registry" class="internalDFN">registry</a> definition for the <em>additionalType</em> property
+    within schema.org, defines <em>additionalType</em> to have an <a>rdfs:subPropertyOf</a>
+    relationship with <code>http://www.w3.org/1999/02/22-rdf-syntax-ns#type</code>.</p>
+
+<div class="example"><div class="example-title"><span>Example 13</span></div><pre class="example">{
+  &quot;http://schema.org/&quot;: {
+    &quot;properties&quot;: {
+      <span class="diff">&quot;additionalType&quot;: {&quot;subPropertyOf&quot;: &quot;http://www.w3.org/1999/02/22-rdf-syntax-ns#type&quot;}</span>
+    }
+}
+
+&lt;div itemscope itemtype=&quot;http://schema.org/Product&quot;&gt;
+  &lt;link itemprop=&quot;additionalType&quot; href=&quot;http://www.productontology.org/id/Laser_printer&quot; /&gt;
+  &lt;p itemprop=&quot;name&quot;&gt;Laser Printer&lt;/a&gt;
+&lt;/div&gt;	</pre></div>
+
+  <p>The previous example, indicates a <a href="#dfn-registry" class="internalDFN">registry</a> rule, which causes the processor to emit
+    an extra triple when first seeing the <code>additionalProperty</code> <a class="aref internalDFN" href="#dfn-itemprop">itemprop</a>:</p>
+
+<div class="example"><div class="example-title"><span>Example 14</span></div><pre class="example">@prefix rdf: &lt;http://www.w3.org/1999/02/22-rdf-syntax-ns#&gt; .
[email protected] rdfa: &lt;http://www.w3.org/ns/rdfa#&gt; .
[email protected] rdfs: &lt;http://www.w3.org/2000/01/rdf-schema#&gt; .
[email protected] schema: &lt;http://schema.org/&gt; .
+
+&lt;&gt; md:item (
+  [ a schema:Product;
+    schema:additionalType &lt;http://www.productontology.org/id/Laser_printer&gt; ;
+    schema:name &quot;Laser Printer&quot;]
+  );
+  rdfa:usesVocabulary schema: .
+
+schema:additionalProperty rdfs:subPropertyOf rdf:type .</pre></div>
+
+  <p>After performing vocabulary expansion, an additional <code>rdf:type</code> triple is generated:</p>
+
+<div class="example"><div class="example-title"><span>Example 15</span></div><pre class="example">@prefix rdf: &lt;http://www.w3.org/1999/02/22-rdf-syntax-ns#&gt; .
[email protected] rdfs: &lt;http://www.w3.org/2000/01/rdf-schema#&gt; .
[email protected] schema: &lt;http://schema.org/&gt; .
+
+&lt;&gt; md:item (
+  [ a schema:Product, &lt;http://www.productontology.org/id/Laser_printer&gt;;
+    schema:additionalType &lt;http://www.productontology.org/id/Laser_printer&gt; ;
+    schema:name &quot;Laser Printer&quot;]
+  )
+  rdfa:usesVocabulary schema: .
+
+schema:additionalProperty rdfs:subPropertyOf rdf:type .</pre></div>
+
+<section id="vocabulary-entailment">
+  <h3><span class="secno">4.1 </span>Vocabulary Entailment</h3>
+  <p>Formally, and for the purpose of vocabulary processing, microdata uses a very
+    restricted subset of the OWL2 vocabulary and is based on the RDF-Based Semantics of OWL2 [<cite><a class="bibref" href="#bib-OWL2-RDF-BASED-SEMANTICS">OWL2-RDF-BASED-SEMANTICS</a></cite>].
+    Vocabulary Entailment uses the following terms: </p>
+  <ul>
+    <li><code>rdfs:subPropertyOf</code></li>
+    <li><code>owl:equivalentProperty</code>
+    </li>
+  </ul>
+  <p>Vocabulary Entailment considers only the entailment on individuals
+    (i.e., not on the relationships that can be deduced on the
+    properties or the classes themselves.)
+  </p>
+  <div class="note"><div class="note-title"><span>Note</span></div><p class="">While the formal definition of the Entailment
+    refers to the general OWL 2 Semantics, practical implementations may
+    rely on a subset of the OWL 2 RL Profile’s entailment expressed in
+    rules
+    (<cite><a href="http://www.w3.org/TR/2009/REC-owl2-profiles-20091027/#Reasoning_in_OWL_2_RL_and_RDF_Graphs_using_Rules">
+      section 4.3</a></cite>
+    of [<cite><a class="bibref" href="#bib-OWL2-PROFILES">OWL2-PROFILES</a></cite>]). The
+    relevant rules are, using the rule identifications in
+    <cite><a href="http://www.w3.org/TR/2009/REC-owl2-profiles-20091027/#Reasoning_in_OWL_2_RL_and_RDF_Graphs_using_Rules">
+      section 4.3</a></cite>
+    of [<cite><a class="bibref" href="#bib-OWL2-PROFILES">OWL2-PROFILES</a></cite>]): <code>prp-spo1</code>, <code>prp-eqp1</code>, and
+    <code>prp-eqp2</code>.</p></div>
+
+  <p>[<cite><a class="bibref" href="#bib-RDFA-CORE">RDFA-CORE</a></cite>] implements a more complete form of vocabulary entailement, 
+    including retrieving the vocabulary URI to find additional class and property expansion definitions, as
+    described in <cite><a href="http://www.w3.org/TR/rdfa-syntax/#s_vocab_entailment">RDFa Vocabulary Entailment</a></cite>.
+    Microdata implementations <em class="rfc2119" title="may">may</em> use RDFa Vocabulary Entailment as an alternative to implementing
+    a separate entailment algorithm. To allow [<cite><a class="bibref" href="#bib-RDFA-CORE">RDFA-CORE</a></cite>] processors to be used for microdata vocabulary expansion, microdata acts as if there is an implicit <code>@vocab</code> RDFa attribute set to a detected vocabulary by emitting
+    a triple using the <code>rdfa:usesVocabulary</code> predicate.</p>
+
+
+  <div class="note"><div class="note-title"><span>Note</span></div><p class="">The entailment described in this section is the <em>minimum</em>
+    useful level for microdata. Processors may, of course, choose to follow
+    more powerful entailment regimes, e.g., include full RDFS [<cite><a class="bibref" href="#bib-RDF-MT">RDF-MT</a></cite>]
+    or OWL2 [<cite><a class="bibref" href="#bib-OWL2-OVERVIEW">OWL2-OVERVIEW</a></cite>] entailments. Using those entailments
+    applications may perform datatype validation by checking <code>rdfs:range</code>
+    of a property, or use the advanced facilities offered by, e.g., OWL2’s
+    property chains to interlink vocabularies further.</p></div>
+
+</section>
+
+<section id="vocabulary-expansion-control-of-microdata-processors">
+  <h3><span class="secno">4.2 </span>Vocabulary Expansion Control of Microdata Processors</h3>
+  <p>Conforming processors <em class="rfc2119" title="must">must</em> perform the basic vocabulary expansion.</p>
+  <p>If vocabulary expansion is performed by the microdata processor using [<cite><a class="bibref" href="#bib-RDFA-CORE">RDFA-CORE</a></cite>] vocabulary expansion, and the
+    <code>vocab_expansion</code> option is passed to the microdata processor,
+    the full [<cite><a class="bibref" href="#bib-RDFA-CORE">RDFA-CORE</a></cite>] expansion <em class="rfc2119" title="must">must</em> also be performed.</p>
+</section>
+</section>
+
+<section id="algorithm">
+  
+<!--OddPage-->
+<h2><span class="secno">5. </span>Algorithm</h2>
+  <p>
+    Transformation of Microdata to RDF makes use of general processing rules described in [<cite><a class="bibref" href="#bib-MICRODATA">MICRODATA</a></cite>]
+    for the treatment of <a href="#dfn-item" class="internalDFN">item</a>s.
+  </p>
+  <section id="algorithm-terms">
+    <h3><span class="secno">5.1 </span>Algorithm Terms</h3>
+    <dl>
+      <dt><dfn id="dfn-absolute-url">absolute URL</dfn></dt><dd>
+        The term <cite><a href="http://www.w3.org/TR/2011/WD-html5-20110525/urls.html#absolute-url">absolute URL</a></cite>
+        is defined in [<cite><a class="bibref" href="#bib-HTML5">HTML5</a></cite>].
+      </dd>
+      <dt><dfn id="dfn-blank-node">blank node</dfn></dt><dd>
+        A blank node is a node in a graph that is neither a <a href="#dfn-uri-reference" class="internalDFN">URI reference</a> nor a <a href="#dfn-literal" class="internalDFN">literal</a>.
+        <a>Item</a>s without a <a href="#dfn-global-identifier" class="internalDFN">global identifier</a> have a blank node allocated to them.
+        (See [<cite><a class="bibref" href="#bib-RDF-CONCEPTS">RDF-CONCEPTS</a></cite>]).
+      </dd>
+      <dt><dfn id="dfn-document-base">document base</dfn></dt><dd>
+        The base address of the document being processed, as defined in <cite><a href="http://www.w3.org/TR/2011/WD-html5-20110525/urls.html#resolving-urls">Resolving URLs</a></cite> in
+        [<cite><a class="bibref" href="#bib-HTML5">HTML5</a></cite>].
+      </dd>
+      <dt><dfn id="dfn-evaluation-context">evaluation context</dfn></dt><dd>
+        A data structure including the following elements:
+        <dl>
+          <dt><dfn id="dfn-memory">memory</dfn></dt><dd>
+            a mapping of items to subjects, initially empty;
+          </dd>
+          <dt><dfn id="dfn-current-name">current name</dfn></dt><dd>
+            an <a href="#dfn-absolute-url" class="internalDFN">absolute URL</a> for the in-scope <a href="#dfn-name" class="internalDFN">name</a>, used for generating URIs
+            for properties of items without an <a href="#dfn-item-type" class="internalDFN">item type</a>;
+            <div class="note"><div class="note-title"><span>Note</span></div><div class="">
+              <a href="#dfn-current-name" class="internalDFN">current name</a> is required for the <code>contextual</code> property URI generation
+              scheme. Without this scheme, this evaluation context component would not be required.
+            </div></div>
+          </dd>
+          <dt><dfn id="dfn-current-type">current type</dfn></dt><dd>
+            an <a href="#dfn-absolute-url" class="internalDFN">absolute URL</a> for the <em>current type</em>, used when an <a href="#dfn-item" class="internalDFN">item</a> does not
+            contain an <a href="#dfn-item-type" class="internalDFN">item type</a>;
+          </dd>
+          <dt><dfn id="dfn-current-vocabulary">current vocabulary</dfn></dt><dd>
+            an <a href="#dfn-absolute-url" class="internalDFN">absolute URL</a> for the <em>current vocabulary</em>, from the <a href="#dfn-registry" class="internalDFN">registry</a>.
+          </dd>
+        </dl>
+      </dd>
+      <dt><dfn id="dfn-item">item</dfn></dt><dd>
+         An <a href="#dfn-item" class="internalDFN">item</a> is described by an element containing an <a class="aref internalDFN" href="#dfn-itemscope">itemscope</a> attribute. The list
+         of top-level microdata items may be retrieved using the
+         <cite><a href="http://www.w3.org/TR/2011/WD-microdata-20110525/#microdata-dom-api">Microdata DOM API</a></cite>
+         <code><cite><a href="http://www.w3.org/TR/2011/WD-microdata-20110525/#dom-document-getitems">document.getItems</a></cite></code>
+         method.
+      </dd>
+      <dt><dfn id="dfn-item-properties">item properties</dfn></dt><dd>
+        The mechanism for finding the <a title="item properties" href="#dfn-item-properties" class="internalDFN">properties of an item</a> The list
+         of item properties items may be retrieved using the
+         <cite><a href="http://www.w3.org/TR/2011/WD-microdata-20110525/#microdata-dom-api">Microdata DOM API</a></cite>
+         <code><cite><a href="http://www.w3.org/TR/2011/WD-microdata-20110525/#dom-properties">element.properties</a></cite></code>
+         attribute.
+      </dd>
+      <dt><dfn id="dfn-fragment-escape">fragment-escape</dfn></dt><dd>
+        The term <cite><a href="http://www.w3.org/TR/2011/WD-html5-20110525/urls.html#fragment-escaped">fragment-escape</a></cite>
+        is defined in [<cite><a class="bibref" href="#bib-HTML5">HTML5</a></cite>]. This involves transforming elements added to URLs to ensure that the result
+        remains a valid URL. The following characters are subject to percent escaping:
+        <ul>
+          <li>U+0022 QUOTATION MARK character (&quot;)</li>
+          <li>U+0023 NUMBER SIGN character (#)</li>
+          <li>U+0025 PERCENT SIGN character (%)</li>
+          <li>U+003C LESS-THAN SIGN character (&lt;)</li>
+          <li>U+003E GREATER-THAN SIGN character (&gt;)</li>
+          <li>U+005B LEFT SQUARE BRACKET character ([)</li>
+          <li>U+005C REVERSE SOLIDUS character (\)</li>
+          <li>U+005D RIGHT SQUARE BRACKET character (])</li>
+          <li>U+005E CIRCUMFLEX ACCENT character (^)</li>
+          <li>U+007B LEFT CURLY BRACKET character ({)</li>
+          <li>U+007C VERTICAL LINE character (|)</li>
+          <li>U+007D RIGHT CURLY BRACKET character (})</li>
+        </ul>
+      </dd>
+      <dt><dfn id="dfn-global-identifier">global identifier</dfn></dt><dd>
+        The value of an <a href="#dfn-item" class="internalDFN">item</a>'s <a href="#dfn-itemid" class="internalDFN">itemid</a> attribute, if it has one. (See <cite><a href="http://www.w3.org/TR/2011/WD-microdata-20110525/#attr-itemscope">Items</a></cite> in
+        [<cite><a class="bibref" href="#bib-MICRODATA">MICRODATA</a></cite>]).
+      </dd>
+      <dt><dfn id="dfn-literal">literal</dfn></dt><dd>
+        Literals are values such as strings and dates, including <dfn id="dfn-typed-literal">typed literal</dfn>s and
+        <dfn id="dfn-plain-literal">plain literal</dfn>s.
+        (See [<cite><a class="bibref" href="#bib-RDF-CONCEPTS">RDF-CONCEPTS</a></cite>]).
+      </dd>
+      <dt><dfn id="dfn-property">property</dfn></dt><dd>
+        Each <a href="#dfn-name" class="internalDFN">name</a> identifies a <a href="#dfn-property" class="internalDFN">property</a> of an <a href="#dfn-item" class="internalDFN">item</a>.
+        An <a href="#dfn-item" class="internalDFN">item</a> may have multiple elements sharing the same <a href="#dfn-name" class="internalDFN">name</a>, creating
+        a multi-valued <a href="#dfn-property" class="internalDFN">property</a>.
+       </dd>
+     <dt><dfn id="dfn-property-names">property names</dfn></dt><dd>
+        The tokens of an element's <a class="aref internalDFN" href="#dfn-itemprop">itemprop</a> attribute. Each token is a <a href="#dfn-name" class="internalDFN">name</a>.
+        (See <cite><a href="http://www.w3.org/TR/2011/WD-microdata-20110525/#property-names">Names: the
+        itemprop attribute</a></cite> in [<cite><a class="bibref" href="#bib-MICRODATA">MICRODATA</a></cite>]).
+      </dd>
+      <dt><dfn id="dfn-property-value">property value</dfn></dt><dd>
+        The <a href="#dfn-property-value" class="internalDFN">property value</a> of a name-value pair added by an element with an <a class="aref internalDFN" href="#dfn-itemprop">itemprop</a>
+        attribute depends on the element.
+        <dl>
+          <dt>If the element has no <a class="aref internalDFN" href="#dfn-itemprop">itemprop</a> attribute</dt>
+          <dd>The value is null and no triple should be generated.</dd>
+          <dt>If the element creates an <a href="#dfn-item" class="internalDFN">item</a> (by having an <a class="aref internalDFN" href="#dfn-itemscope">itemscope</a> attribute)</dt>
+          <dd>
+            The value is the <a href="#dfn-uri-reference" class="internalDFN">URI reference</a> or <a href="#dfn-blank-node" class="internalDFN">blank node</a> returned from
+            <a href="#generate-the-triples">generate the triples</a> for that <a href="#dfn-item" class="internalDFN">item</a>.
+          </dd>
+          <dt>If the element is a URL property element (<code>a</code>, <code>area</code>, <code>audio</code>,
+            <code>embed</code>, <code>iframe</code>, <code>img</code>, <code>link</code>, <code>object</code>,
+            <code>source</code>, <code>track</code> or <code>video</code>)</dt>
+          <dd>
+            The value is a <a href="#dfn-uri-reference" class="internalDFN">URI reference</a> created from <code><cite>
+              <a href="http://www.w3.org/TR/2011/WD-microdata-20110525/#dom-itemvalue">element.itemValue</a></cite></code>.
+              (See relevant attribute descriptions in [<cite><a class="bibref" href="#bib-HTML5">HTML5</a></cite>]).
+          </dd>
+          <dt>If the element is a <code>time</code> element.</dt>
+          <dd>The value is a <a href="#dfn-literal" class="internalDFN">literal</a> made from <code><cite>
+            <a href="http://www.w3.org/TR/2011/WD-microdata-20110525/#dom-itemvalue">element.itemValue</a></cite></code>.
+            <dl>
+              <dt>
+                If the value is a
+                <cite><a href="http://www.w3.org/TR/2011/WD-html5-20110525/common-microsyntaxes.html#valid-date-string">
+                  valid date string
+                </a></cite>
+                having the lexical form of
+                <cite><a href="http://www.w3.org/TR/xmlschema-2/#date">xsd:date</a></cite> [<cite><a class="bibref" href="#bib-RDF-SCHEMA">RDF-SCHEMA</a></cite>].
+              </dt>
+              <dd>
+                The value is a <a href="#dfn-typed-literal" class="internalDFN">typed literal</a> composed of the value and
+                <code>http://www.w3.org/2001/XMLSchema#date</code>.
+              </dd>
+              <dt>
+                If the value is a
+                <cite><a href="http://www.w3.org/TR/2011/WD-html5-20110525/common-microsyntaxes.html#valid-time-string">
+                  valid time string
+                </a></cite>
+                having the lexical form of
+                <cite><a href="http://www.w3.org/TR/xmlschema-2/#time">xsd:time</a></cite> [<cite><a class="bibref" href="#bib-RDF-SCHEMA">RDF-SCHEMA</a></cite>].
+              </dt>
+              <dd>
+                The value is a <a href="#dfn-typed-literal" class="internalDFN">typed literal</a> composed of the value and
+                <code>http://www.w3.org/2001/XMLSchema#time</code>.
+              </dd>
+              <dt>
+                If the value is a
+                <cite><a href="http://www.w3.org/TR/2011/WD-html5-20110525/common-microsyntaxes.html#valid-local-date-and-time-string">
+                  valid local date and time string
+                </a></cite>
+                or
+                <cite><a href="http://www.w3.org/TR/2011/WD-html5-20110525/common-microsyntaxes.html#valid-global-date-and-time-string">
+                  valid global date and time string
+                </a></cite>
+                having the lexical form of
+                <cite><a href="http://www.w3.org/TR/xmlschema-2/#dateTime">xsd:dateTime</a></cite> [<cite><a class="bibref" href="#bib-RDF-SCHEMA">RDF-SCHEMA</a></cite>].
+              </dt>
+              <dd>
+                The value is a <a href="#dfn-typed-literal" class="internalDFN">typed literal</a> composed of the value and
+               <code>http://www.w3.org/2001/XMLSchema#dateTime</code>.
+              </dd>
+              <dt>
+                If the value is a
+                <cite><a href="http://www.w3.org/TR/2011/WD-html5-20110525/common-microsyntaxes.html#valid-month-string">
+                  valid month string
+                </a></cite>
+                having the lexical form of
+                <cite><a href="http://www.w3.org/TR/xmlschema-2/#gYearMonth">xsd:gYearMonth</a></cite> [<cite><a class="bibref" href="#bib-RDF-SCHEMA">RDF-SCHEMA</a></cite>].
+              </dt>
+              <dd>
+                The value is a <a href="#dfn-typed-literal" class="internalDFN">typed literal</a> composed of the value and
+               <code>http://www.w3.org/2001/XMLSchema#gYearMonth</code>.
+              </dd>
+              <dt>
+                If the value is a
+                <cite><a href="http://www.w3.org/TR/2011/WD-html5-20110525/common-microsyntaxes.html#valid-non-negative-integer">
+                  valid non-negative integer
+                </a></cite>
+                having the lexical form of
+                <cite><a href="http://www.w3.org/TR/xmlschema-2/#gYear">xsd:gYear</a></cite> [<cite><a class="bibref" href="#bib-RDF-SCHEMA">RDF-SCHEMA</a></cite>].
+              </dt>
+              <dd>
+                The value is a <a href="#dfn-typed-literal" class="internalDFN">typed literal</a> composed of the value and
+               <code>http://www.w3.org/2001/XMLSchema#gYear</code>.
+              </dd>
+              <dt>
+                If the value has the lexical form of
+                <cite><a href="http://www.w3.org/TR/xmlschema-2/#duration">xsd:duration</a></cite>
+                [<cite><a class="bibref" href="#bib-RDF-SCHEMA">RDF-SCHEMA</a></cite>].
+                
+<!--
+                If the value is a
+                <cite><a href="http://dev.w3.org/html5/spec/Overview.html#valid-duration-string">
+                  valid duration string
+                </a></cite>
+                having the lexical form of
+                <cite><a href="http://www.w3.org/TR/xmlschema-2/#duration">xsd:duration</a></cite> [[!RDF-SCHEMA]].
+                -->
+
+              </dt>
+              <dd>
+                The value is a <a href="#dfn-typed-literal" class="internalDFN">typed literal</a> composed of the value and
+                <code>http://www.w3.org/2001/XMLSchema#duration</code>.
+                <div class="note"><div class="note-title"><span>Note</span></div><p class="">The referenced version of [<cite><a class="bibref" href="#bib-HTML5">HTML5</a></cite>] does not include a <em>duration</em> data type,
+                  but it is in the Editor's Draft and is expected to be included in a
+                  forthcoming update to the Working Draft</p></div>
+              </dd>
+              <dt>Otherwise</dt>
+              <dd>
+                The value is a <a href="#dfn-plain-literal" class="internalDFN">plain literal</a> created from the value with language information set from the
+                <cite><a href="http://www.w3.org/TR/2011/WD-html5-20110525/elements.html#language">language</a></cite>
+                of the property element.
+                <div class="note"><div class="note-title"><span>Note</span></div><p class="">The HTML
+                  <em>valid yearless date string</em>
+                  is similar to
+                  <cite><a href="http://www.w3.org/TR/xmlschema-2/#gMonthDay">xsd:gMonthDay</a></cite>,
+                  but the lexical forms differ, so it is not included in this conversion.</p></div>
+              </dd>
+            </dl>
+            <p>See
+              <cite><a href="http://www.w3.org/TR/2011/WD-html5-20110525/rendering.html#the-time-element-0">
+                The <code>time</code> element
+              </a></cite>
+              in [<cite><a class="bibref" href="#bib-HTML5">HTML5</a></cite>].</p>
+          </dd>
+          <dt>Otherwise</dt>
+          <dd>The value is a <a href="#dfn-plain-literal" class="internalDFN">plain literal</a> created from the value with language information set from the
+            <cite><a href="http://www.w3.org/TR/2011/WD-html5-20110525/elements.html#language">language</a></cite> of the property element.
+            <p>See
+              <cite><a href="http://www.w3.org/TR/2011/WD-html5-20110525/elements.html#the-lang-and-xml:lang-attributes">
+                The <code>lang</code> and <code>xml:lang</code> attributes
+              </a></cite>
+              in [<cite><a class="bibref" href="#bib-HTML5">HTML5</a></cite>] for determining the language of a node.</p>
+          </dd>
+        </dl>
+      </dd>
+      <dt><dfn id="dfn-top-level-item">top-level item</dfn></dt><dd>
+        An <a href="#dfn-item" class="internalDFN">item</a> which does not contain an <a class="aref internalDFN" href="#dfn-itemprop">itemprop</a> attribute.
+        Available through the <cite><a href="http://www.w3.org/TR/2011/WD-microdata-20110525/#microdata-dom-api">Microdata DOM API</a></cite> as
+        <code>document.getItems</code>.
+        (See <cite><a href="http://www.w3.org/TR/2011/WD-microdata-20110525/#top-level-microdata-items">Associating names with items</a></cite> in [<cite><a class="bibref" href="#bib-MICRODATA">MICRODATA</a></cite>]).
+      </dd>
+      <dt><dfn id="dfn-uri-reference">URI reference</dfn></dt><dd>
+        URI references are suitable to be used in <em>subject</em>, <em>predicate</em> or <em>object</em> positions
+        within an RDF triple, as opposed to a <a href="#dfn-literal" class="internalDFN">literal</a> value that may contain a string representation of a
+        URI. (See [<cite><a class="bibref" href="#bib-RDF-CONCEPTS">RDF-CONCEPTS</a></cite>]).
+        <div class="issue"><div class="issue-title"><span>Issue</span></div><div class="">
+          <p>The HTML5/microdata content model for <code>@href</code>, <code>@src</code>,
+            <code>@data</code>, <a class="aref internalDFN" href="#dfn-itemtype">itemtype</a> and <a class="aref internalDFN" href="#dfn-itemprop">itemprop</a> and <a class="aref internalDFN" href="#dfn-itemid">itemid</a> is that of
+            a URL, not a URI or IRI.</p>
+          <p>A proposed mechanism for specifying the range of <a href="#dfn-property-value" class="internalDFN">property value</a>s to be URI reference or IRI could
+            allow these to be specified as subject or object using a <code>@content</code> attribute.</p>
+        </div></div>
+      </dd>
+      <dt><dfn id="dfn-vocabulary">vocabulary</dfn></dt><dd>
+        A vocabulary is a collection of URIs, suitable for use as an <a class="aref internalDFN" href="#dfn-itemtype">itemtype</a> or <a class="aref internalDFN" href="#dfn-itemprop">itemprop</a>
+        value, that share a common <a href="#dfn-uri-prefix" class="internalDFN">URI prefix</a>. That prefix is the vocabulary URI. A vocabulary URI is not
+        allowed to be a prefix of another vocabulary URI.
+        <div class="note"><div class="note-title"><span>Note</span></div><div class="">
+          This definition differs from the language in the HTML spec and is just for the purpose of this
+          document. In HTML, a vocabulary is a specification, and doesn't have a URI. In our view, if one
+          specification defines ten <a class="aref internalDFN" href="#dfn-itemtype">itemtype</a>s, then these could be treated as one vocabulary or as ten
+          distinct vocabularies; it is entirely up to the vocabulary creator.
+        </div></div>
+      </dd>
+    </dl>
+  </section>
+
+  <section id="rdf-conversion-algorithm">
+    <h3><span class="secno">5.2 </span>RDF Conversion Algorithm</h3>
+    <p>A HTML document containing microdata <em class="rfc2119" title="may">may</em> be converted to any other RDF-compatible document
+    format using the algorithm specified in this section.</p>
+    <p>A conforming microdata processor implementing RDF conversion <em class="rfc2119" title="must">must</em> implement a
+      processing algorithm that results in the equivalent triples to those that the following
+      algorithm generates:</p>
+
+    <p>Set <em>item list</em> to an empty list.</p>
+
+    <ol class="algorithm">
+      <li>For each element that is also a <a href="#dfn-top-level-item" class="internalDFN">top-level item</a> run the following algorithm:
+        <ol class="algorithm">
+          <li>
+            <a href="#generate-the-triples">Generate the triples</a> for an item <em>item</em>, using the
+            <a href="#dfn-evaluation-context" class="internalDFN">evaluation context</a>.
+            Let <em>result</em> be the (<a href="#dfn-uri-reference" class="internalDFN">URI reference</a> or <a href="#dfn-blank-node" class="internalDFN">blank node</a>) subject returned.
+          </li>
+          <li>
+            Append <em>result</em> to <em>item list</em>.
+          </li>
+        </ol>
+      </li>
+      <li>
+        <a href="#generate-collection">Generate an RDF Collection</a> <em>list</em> from the ordered list of values.
+        Set <em>value</em> to the value returned from <a href="#generate-collection">generate an RDF
+        Collection</a>.
+      </li>
+      <li>
+        Generate the following triple:
+        <dl class="triple">
+          <dt>subject</dt>
+          <dd><a href="#dfn-document-base" class="internalDFN">document base</a></dd>
+          <dt>predicate</dt>
+          <dd><code>http://www.w3.org/ns/md#item</code></dd>
+          <dt>object</dt>
+          <dd><em>value</em></dd>
+        </dl>
+      </li>
+      <li>
+        Perform <a href="#vocabulary-entailment">Vocabulary Entailment</a>.</li>
+    </ol>
+  </section>
+
+  <section id="generate-the-triples">
+    <h3><span class="secno">5.3 </span>Generate the triples</h3>
+    <p>
+      When the user agent is to Generate triples for an <a href="#dfn-item" class="internalDFN">item</a> <em>item</em>, given
+      <a href="#dfn-evaluation-context" class="internalDFN">evaluation context</a>, it must run the following steps:
+    </p>
+    <div class="note"><div class="note-title"><span>Note</span></div><p class="">
+      This algorithm has undergone substantial change from the original microdata specification [<cite><a class="bibref" href="#bib-MICRODATA">MICRODATA</a></cite>].
+    </p></div>
+    <ol class="algorithm">
+      <li>
+        If there is an entry for <em>item</em> in <a href="#dfn-memory" class="internalDFN">memory</a>, then let <em>subject</em> be the subject of
+        that entry. Otherwise, if <em>item</em> has a <a href="#dfn-global-identifier" class="internalDFN">global identifier</a> and that
+        <a href="#dfn-global-identifier" class="internalDFN">global identifier</a> is an <a href="#dfn-absolute-url" class="internalDFN">absolute URL</a>, let <em>subject</em> be that
+        <a href="#dfn-global-identifier" class="internalDFN">global identifier</a>. Otherwise, let <em>subject</em> be a new <a href="#dfn-blank-node" class="internalDFN">blank node</a>.
+      </li>
+      <li>Add a mapping from <em>item</em> to <em>subject</em> in <a href="#dfn-memory" class="internalDFN">memory</a></li>
+      <li>
+        For each <em>type</em> returned from
+        <code><cite><a href="http://www.w3.org/TR/2011/WD-microdata-20110525/#dom-itemtype">element.itemType</a></cite></code>
+        of the element defining the <a href="#dfn-item" class="internalDFN">item</a>.
+        <ol class="algorithm">
+          <li>If <em>type</em> is an <a href="#dfn-absolute-url" class="internalDFN">absolute URL</a>, generate the following triple:
+            <dl class="triple">
+              <dt>subject</dt>
+              <dd><em>subject</em></dd>
+              <dt>predicate</dt>
+              <dd><code>http://www.w3.org/1999/02/22-rdf-syntax-ns#type</code></dd>
+              <dt>object</dt>
+              <dd><em>type</em> (as a <a href="#dfn-uri-reference" class="internalDFN">URI reference</a>)</dd>
+            </dl>
+          </li>
+        </ol>
+      </li>
+      <li>
+        Set <em>type</em> to the first value returned from
+        <code><cite><a href="http://www.w3.org/TR/2011/WD-microdata-20110525/#dom-itemtype">element.itemType</a></cite></code>
+        of the element defining the <a href="#dfn-item" class="internalDFN">item</a>.
+      </li>
+      <li>If <em>type</em> is an <a href="#dfn-absolute-url" class="internalDFN">absolute URL</a>, set <a href="#dfn-current-name" class="internalDFN">current name</a> in
+        <a href="#dfn-evaluation-context" class="internalDFN">evaluation context</a> to null.</li>
+      <li>
+        Otherwise, set <em>type</em> to <a href="#dfn-current-type" class="internalDFN">current type</a> from
+        <a href="#dfn-evaluation-context" class="internalDFN">evaluation context</a> if not empty.
+      </li>
+      <li>If the <a href="#dfn-registry" class="internalDFN">registry</a> contains a <a href="#dfn-uri-prefix" class="internalDFN">URI prefix</a> that is a
+        character for character match of <em>type</em> up to the length of the 
+        <a href="#dfn-uri-prefix" class="internalDFN">URI prefix</a>, set <em>vocab</em> as that <a href="#dfn-uri-prefix" class="internalDFN">URI prefix</a> and 
+        generate the following triple:
+        <dl class="triple">
+          <dt>subject</dt>
+          <dd><a href="#dfn-document-base" class="internalDFN">document base</a></dd>
+          <dt>predicate</dt>
+          <dd><code>http://www.w3.org/ns/rdfa#usesVocabulary</code></dd>
+          <dt>object</dt>
+          <dd><em>vocab</em> (as a <a href="#dfn-uri-reference" class="internalDFN">URI reference</a>)</dd>
+        </dl>
+      </li>
+      <li>Otherwise, if type is not empty, construct <em>vocab</em> by removing everything following the last
+        SOLIDUS U+002F (&quot;/&quot;) or NUMBER SIGN U+0023 (&quot;#&quot;) from the <em>path</em> component of <em>type</em>.</li>
+      <li>Update <a href="#dfn-evaluation-context" class="internalDFN">evaluation context</a> setting <a href="#dfn-current-vocabulary" class="internalDFN">current vocabulary</a> to <em>vocab</em>.</li> 
+      <li>
+        Set <em>property list</em> to an empty array mapping properties to one or more
+        <em>value</em>s as established below.
+      </li>
+      <li>
+        For each element <em>element</em> that has one or more <a href="#dfn-property-names" class="internalDFN">property names</a> and is one of the
+        <a title="item properties" href="#dfn-item-properties" class="internalDFN">properties of the item</a> <em>item</em>, in the order those elements
+        are given by the algorithm that returns the <a title="item properties" href="#dfn-item-properties" class="internalDFN">properties of the item</a>,
+        run the following substep:
+        <ol class="algorithm">
+          <li>
+            For each <em>name</em> in the element's <a href="#dfn-property-names" class="internalDFN">property names</a>, run the following substeps:
+            <ol class="algorithm">
+              <li>
+                Let <em>context</em> be a copy of <a href="#dfn-evaluation-context" class="internalDFN">evaluation context</a> with <a href="#dfn-current-type" class="internalDFN">current type</a> set
+                to <em>type</em>.
+              </li>
+              <li>
+                Let <em>predicate</em> be the result of <a href="#generate-predicate-uri">generate predicate URI</a>
+                using <em>context</em> and <em>name</em>.
+                 Update <em>context</em> by setting <a href="#dfn-current-name" class="internalDFN">current name</a> to <em>predicate</em>.
+              </li>
+              <li>
+                Let <em>value</em> be the <a href="#dfn-property-value" class="internalDFN">property value</a> of <em>element</em>.
+              </li>
+              <li>
+                If <em>value</em> is an <a href="#dfn-item" class="internalDFN">item</a>, then <a href="#generate-the-triples">generate the
+                triples</a> for <em>value</em> using <em>context</em>. Replace <em>value</em> by the subject returned
+                from those steps.
+              </li>
+              <li>
+                Add <em>value</em> to <em>property list</em> for <em>predicate</em>.
+              </li>
+            </ol>
+          </li>
+        </ol>
+      </li>
+      <li>
+        For each <em>predicate</em> in <em>property list</em>:
+        <ol class="algorithm">
+          <li><a href="#generate-property-values">Generate property values</a> <em>subject</em>, <em>predicate</em> and
+            the list of values associated with <em>predicate</em> from <em>property list</em> as <em>values</em>.
+          </li>
+        </ol>
+      </li>
+      <li>Return <em>subject</em></li>
+    </ol>
+  </section>
+  
+  <section id="generate-predicate-uri">
+    <h3><span class="secno">5.4 </span>Generate Predicate URI</h3>
+    <p>Predicate URI generation makes use of <a href="#dfn-current-type" class="internalDFN">current type</a>,
+      <a href="#dfn-current-name" class="internalDFN">current name</a>, and <a href="#dfn-current-vocabulary" class="internalDFN">current vocabulary</a> from an <a href="#dfn-evaluation-context" class="internalDFN">evaluation
+      context</a> <em>context</em> along with <em>name</em>.</p>
+
+    <ol class="algorithm">
+      <li>If <em>name</em> is an <a href="#dfn-absolute-url" class="internalDFN">absolute URL</a>, return <em>name</em>
+        as a <a href="#dfn-uri-reference" class="internalDFN">URI reference</a>.</li>
+      <li>If <a href="#dfn-current-type" class="internalDFN">current type</a> from <em>context</em> is null,
+        there can be no <a href="#dfn-current-vocabulary" class="internalDFN">current vocabulary</a>. Return the <a href="#dfn-uri-reference" class="internalDFN">URI reference</a>
+        that is the <a href="#dfn-document-base" class="internalDFN">document base</a> with its <cite><a href="http://tools.ietf.org/html/rfc3986#section-3.5">fragment</a></cite>
+        set to the <a href="#dfn-fragment-escape" class="internalDFN">fragment-escape</a>d value of <em>name</em>.
+        <div class="note"><div class="note-title"><span>Note</span></div><div class="">
+          This rule is intended to allow for a the case where no type is set, and
+          therefore there is no vocabulary from which to extract rules. For
+          example, if there is a <a href="#dfn-document-base" class="internalDFN">document base</a> of
+          <code>http://example.org/doc</code> and an <a class="aref internalDFN" href="#dfn-itemprop">itemprop</a>
+          of 'title', a URI will be constructed to be
+          <code>http://example.org/doc#title</code>.
+        </div></div>
+      </li>
+      <li>Otherwise, if <a href="#dfn-current-vocabulary" class="internalDFN">current vocabulary</a> from <em>context</em>
+        is not null and <a href="#dfn-registry" class="internalDFN">registry</a> has an entry for <a href="#dfn-current-vocabulary" class="internalDFN">current vocabulary</a>
+        having a <a href="#dfn-propertyuri" class="internalDFN">propertyURI</a> entry that is not null, set that as
+        <em>scheme</em>. Otherwise, set <em>scheme</em> to
+        <code>vocabulary</code>.</li>
+      <li id="scheme-vocab">If <em>scheme</em> is <code>vocabulary</code>
+        set <em>expandedURI</em> to the <a href="#dfn-uri-reference" class="internalDFN">URI reference</a> constructed by
+        appending the <a href="#dfn-fragment-escape" class="internalDFN">fragment-escape</a>d value of <em>name</em> to <a href="#dfn-current-vocabulary" class="internalDFN">current
+        vocabulary</a>, separated by a U+0023 NUMBER SIGN character (#) unless the
+        <a href="#dfn-current-vocabulary" class="internalDFN">current vocabulary</a> ends with either a U+0023 NUMBER SIGN character
+        (#) or SOLIDUS U+002F (/).</li>
+      <li id="scheme-context">Otherwise, if <em>scheme</em> is
+        <code>contextual</code>, set <em>expandedURI</em> to the <a href="#dfn-uri-reference" class="internalDFN">URI
+        reference</a> constructed as follows:
+        <ol class="algorithm">
+          <li>Let <em>s</em> be <a href="#dfn-current-name" class="internalDFN">current name</a> from <em>context</em>.</li>
+          <li>If <code>http://www.w3.org/ns/md?type=</code>
+            is a prefix of <em>s</em>, return the concatenation of <em>s</em>, a
+            U+002E FULL STOP character (.) and the <a href="#dfn-fragment-escape" class="internalDFN">fragment-escape</a>d value
+            of <em>name</em>.</li>
+          <li>Otherwise, return the concatenation of
+            <code>http://www.w3.org/ns/md?type=</code>, the
+            <a href="#dfn-fragment-escape" class="internalDFN">fragment-escape</a>d value of <a href="#dfn-current-type" class="internalDFN">current type</a>, the string
+            <code>&amp;prop=</code>, and the <a href="#dfn-fragment-escape" class="internalDFN">fragment-escape</a>d value of
+            <em>name</em>. </li>
+        </ol>
+      </li>
+      <li>If the <a href="#dfn-registry" class="internalDFN">registry</a> entry for <a href="#dfn-propertyuri" class="internalDFN">propertyURI</a>
+        has an <code>equivalentProperty</code> key,
+        generate the following triple using the
+        <em>value</em> of that key:
+        <dl class="triple">
+          <dt>subject</dt>
+          <dd><em>expandedURI</em></dd>
+          <dt>predicate</dt>
+          <dd><code>http://www.w3.org/2002/07/owl#equivalentProperty</code></dd>
+          <dt>object</dt>
+          <dd><em>value</em></dd>
+        </dl>
+        <p>If the value is an array, generate a triple for each value of that array.</p>
+      </li>
+      <li>If the <a href="#dfn-registry" class="internalDFN">registry</a> entry for <a href="#dfn-propertyuri" class="internalDFN">propertyURI</a>
+        has an <code>subPropertyOf</code> key, generate the following triple using the
+        <em>value</em> of that key:
+        <dl class="triple">
+          <dt>subject</dt>
+          <dd><em>expandedURI</em></dd>
+          <dt>predicate</dt>
+          <dd><code>http://www.w3.org/2000/01/rdf-schema#subPropertyOf</code></dd>
+          <dt>object</dt>
+          <dd><em>value</em></dd>
+        </dl>
+        <p>If the value is an array, generate a triple for each value of that array.</p>
+      </li>
+      <li>Return <em>expandedURI</em>.</li>
+    </ol>
+  </section>
+  
+  <section id="generate-property-values">
+    <h3><span class="secno">5.5 </span>Generate Property Values</h3>
+    <p>Property value serialization makes use of <em>subject</em>, <em>predicate</em> and <em>values</em>.</p>
+
+    <ol class="algorithm">
+      <li>If the <a href="#dfn-registry" class="internalDFN">registry</a> contains a URI prefix that is a character for character match of
+        <em>predicate</em> up to the length of the URI prefix, set <em>vocab</em> as that URI prefix.
+         Otherwise set <em>vocab</em> to null.</li>
+      <li>If <em>vocab</em> is not null
+        and <a href="#dfn-registry" class="internalDFN">registry</a> has an entry for <em>vocab</em> that is a JSON Object, let
+        <em>registry object</em> be that value. Otherwise set <em>registry object</em> to null.</li>
+      <li>If <em>registry object</em> is not null and <em>registry object</em> contains key
+        <a href="#dfn-properties" class="internalDFN"><code>properties</code></a>
+        which has a JSON Object value, let <em>properties</em> be that value. Otherwise, set <em>properties</em>
+        to null.</li>
+      <li>If <em>properties</em> is not null, and <em>properties</em> contains a key, which after
+        <a href="#generate-predicate-uri">Generate Predicate URI</a> expansion has a value which is a JSON Object, let
+        <em>property override</em> be that value. Otherwise, set <em>property override</em> to null.</li>
+      <li>If <em>property override</em> contains the key
+        <a href="#dfn-multiplevalues" class="internalDFN"><code>multipleValues</code></a>, set that as <em>method</em>.</li>
+      <li>Otherwise, if <em>registry object</em> con  contains the key
+        <a href="#dfn-multiplevalues" class="internalDFN"><code>multipleValues</code></a>, set that as <em>method</em>.</li>
+      <li>Otherwise, set <em>method</em> to <code>unordered</code>.</li>
+      <li id="values-unordered">If <em>method</em> is <code>unordered</code>,
+        for each <em>value</em> in <em>values</em>, generate the following triple:
+        <dl class="triple">
+          <dt>subject</dt>
+          <dd><em>subject</em></dd>
+          <dt>predicate</dt>
+          <dd><em>predicate</em></dd>
+          <dt>object</dt>
+          <dd><em>value</em></dd>
+        </dl>
+      </li>
+      <li id="values-list">Otherwise, if <em>method</em> is <code>list</code>:
+        <ol class="algorithm">
+          <li>Set <em>value</em> to the value returned from <a href="#generate-collection">generate an RDF
+            Collection</a>.
+          </li>
+          <li>
+            Generate the following triple:
+            <dl class="triple">
+              <dt>subject</dt>
+              <dd><em>subject</em></dd>
+              <dt>predicate</dt>
+              <dd><em>predicate</em></dd>
+              <dt>object</dt>
+              <dd><em>value</em></dd>
+            </dl>
+          </li>
+        </ol>
+      </li>
+    </ol>
+  </section>
+
+  <section id="generate-collection">
+    <h3><span class="secno">5.6 </span>Generate RDF Collection</h3>
+    <p>
+      An <dfn id="dfn-rdf-collection">RDF Collection</dfn> is a mechanism for defining ordered sequences of objects in RDF (See <cite><a href="http://www.w3.org/TR/rdf-syntax/#collections">RDF Collections</a></cite> in
+      [<cite><a class="bibref" href="#bib-RDF-SCHEMA">RDF-SCHEMA</a></cite>]). As the RDF data-model is that of an unordered graph, a linking method using properties
+      <code>rdf:first</code> and <code>rdf:next </code>is required to be able to specify a particular order.
+    </p>
+    <p>
+      In the microdata to RDF mapping, <a href="#dfn-rdf-collection" class="internalDFN">RDF Collection</a>s are used when an item has more than one value
+      associated with a given property to ensure that the original document order is maintained. The following
+      procedure should be used to generate triples when an <a href="#dfn-item" class="internalDFN">item</a> property has more than one value
+      (contained in <em>list</em>):
+    </p>
+    <ol class="algorithm">
+      <li>
+        Create a new array <em>array</em> containing a <a href="#dfn-blank-node" class="internalDFN">blank node</a> for every value in <em>list</em>.
+      </li>
+      <li>
+        For each pair of <em>bnode</em> from <em>array</em> and <em>value</em> from <em>list</em> the following
+        triple is generated:
+        <dl class="triple">
+          <dt>subject</dt>
+          <dd><em>bnode</em></dd>
+          <dt>predicate</dt>
+          <dd><code>http://www.w3.org/1999/02/22-rdf-syntax-ns#first</code></dd>
+          <dt>object</dt>
+          <dd><em>value</em></dd>
+        </dl>
+      </li>
+      <li>
+        For each <em>bnode</em> in <em>array</em> the following triple is generated:
+        <dl class="triple">
+          <dt>subject</dt>
+          <dd><em>bnode</em></dd>
+          <dt>predicate</dt>
+          <dd><code>http://www.w3.org/1999/02/22-rdf-syntax-ns#rest</code></dd>
+          <dt>object</dt>
+          <dd>
+            next <em>bnode</em> in <em>array</em> or, if that does not exist,
+            <code>http://www.w3.org/1999/02/22-rdf-syntax-ns#nil</code>
+          </dd>
+        </dl>
+      </li>
+      <li>
+        Return the first <a href="#dfn-blank-node" class="internalDFN">blank node</a> from <em>array</em>.
+      </li>
+    </ol>
+  </section>
+</section>
+
+<section class="appendix informative" id="testing">
+  
+<!--OddPage-->
+<h2><span class="secno">A. </span>Testing</h2><p><em>This section is non-normative.</em></p>
+  <p>A test suite [<cite><a class="bibref" href="#bib-MICRODATA-RDF-TESTS">MICRODATA-RDF-TESTS</a></cite>] under development to help processor developers verify
+    conformance to this specification.</p>
+</section>
+
+<section class="appendix informative" id="markup-examples">
+
+<!--OddPage-->
+<h2><span class="secno">B. </span>Markup Examples</h2><p><em>This section is non-normative.</em></p>
+
+<p>The microdata example below expresses book information as an FRBR Work item.</p>
+
+<div class="example"><div class="example-title"><span>Example 16</span></div><pre class="example">&lt;dl itemscope
+    itemtype=&quot;http://purl.org/vocab/frbr/core#Work&quot;
+    itemid=&quot;http://books.example.com/works/45U8QJGZSQKDH8N&quot;
+    lang=&quot;en&quot;&gt;
+ &lt;dt&gt;Title&lt;/dt&gt;
+ &lt;dd&gt;&lt;cite itemprop=&quot;http://purl.org/dc/terms/title&quot;&gt;Just a Geek&lt;/cite&gt;&lt;/dd&gt;
+ &lt;dt&gt;By&lt;/dt&gt;
+ &lt;dd&gt;&lt;span itemprop=&quot;http://purl.org/dc/terms/creator&quot;&gt;Wil Wheaton&lt;/span&gt;&lt;/dd&gt;
+ &lt;dt&gt;Format&lt;/dt&gt;
+ &lt;dd itemprop=&quot;http://purl.org/vocab/frbr/core#realization&quot;
+     itemscope
+     itemtype=&quot;http://purl.org/vocab/frbr/core#Expression&quot;
+     itemid=&quot;http://books.example.com/products/9780596007683.BOOK&quot;&gt;
+  &lt;link itemprop=&quot;http://purl.org/dc/terms/type&quot; href=&quot;http://books.example.com/product-types/BOOK&quot;&gt;
+  Print
+ &lt;/dd&gt;
+ &lt;dd itemprop=&quot;http://purl.org/vocab/frbr/core#realization&quot;
+     itemscope
+     itemtype=&quot;http://purl.org/vocab/frbr/core#Expression&quot;
+     itemid=&quot;http://books.example.com/products/9780596802189.EBOOK&quot;&gt;
+  &lt;link itemprop=&quot;http://purl.org/dc/terms/type&quot; href=&quot;http://books.example.com/product-types/EBOOK&quot;&gt;
+  Ebook
+ &lt;/dd&gt;
+&lt;/dl&gt;</pre></div>
+
+<p>Assuming that <a href="#dfn-registry" class="internalDFN">registry</a> contains a an entry for <code>http://purl.org/vocab/frbr/core#</code>
+  with <a href="#dfn-propertyuri" class="internalDFN"><code>propertyURI</code></a> set to <code>vocabulary</code>,
+  this is equivalent to the following Turtle:</p>
+<div class="example"><div class="example-title"><span>Example 17</span></div><pre class="example">@prefix dc: &lt;http://purl.org/dc/terms/&gt; .
[email protected] md: &lt;http://www.w3.org/ns/md#&gt; .
[email protected] frbr: &lt;http://purl.org/vocab/frbr/core#&gt; .
[email protected] rdfa: &lt;http://www.w3.org/ns/rdfa#&gt; .
+
+&lt;&gt; md:item (&lt;http://books.example.com/works/45U8QJGZSQKDH8N&gt;) ;
+  rdfa:usesVocabulary frbr: .
+
+&lt;http://books.example.com/works/45U8QJGZSQKDH8N&gt; a frbr:Work ;
+  dc:creator &quot;Wil Wheaton&quot;@en ;
+  dc:title &quot;Just a Geek&quot;@en ;
+  frbr:realization &lt;http://books.example.com/products/9780596007683.BOOK&gt;,
+    &lt;http://books.example.com/products/9780596802189.EBOOK&gt; .
+
+&lt;http://books.example.com/products/9780596007683.BOOK&gt; a frbr:Expression ;
+  dc:type &lt;http://books.example.com/product-types/BOOK&gt; .
+
+&lt;http://books.example.com/products/9780596802189.EBOOK&gt; a frbr:Expression ;
+  dc:type &lt;http://books.example.com/product-types/EBOOK&gt; .</pre></div>
+
+<p>The following snippet of HTML has microdata for two people with the same address. This illustrates two
+  <a href="#dfn-item" class="internalDFN">item</a>s referencing a third item, and how only a single RDF resource definition is created
+  for that third item.</p>
+<div class="example"><div class="example-title"><span>Example 18</span></div><pre class="example">&lt;p&gt;
+ Both
+ &lt;span itemscope itemtype=&quot;http://microformats.org/profile/hcard&quot; itemref=&quot;home&quot;&gt;
+   &lt;span itemprop=&quot;fn&quot;
+       &gt;&lt;span itemprop=&quot;n&quot; itemscope
+       &gt;&lt;span itemprop=&quot;given-name&quot;&gt;Princeton&lt;/span&gt;&lt;/span&gt;&lt;/span&gt;
+  &lt;/span&gt;
+ and
+ &lt;span itemscope itemtype=&quot;http://microformats.org/profile/hcard&quot; itemref=&quot;home&quot;&gt;
+   &lt;span itemprop=&quot;fn&quot;
+     &gt;&lt;span itemprop=&quot;n&quot; itemscope
+       &gt;&lt;span itemprop=&quot;given-name&quot;&gt;Trekkie&lt;/span&gt;&lt;/span&gt;&lt;/span&gt;
+  &lt;/span&gt;
+ live at
+ &lt;span id=&quot;home&quot; itemprop=&quot;adr&quot; itemscope&gt;
+   &lt;span itemprop=&quot;street-address&quot;&gt;Avenue Q&lt;/span&gt;.
+ &lt;/span&gt;
+&lt;/p&gt;</pre></div>
+
+<p>Assuming that <a href="#dfn-registry" class="internalDFN">registry</a> contains a an entry for <code>http://microformats.org/profile/hcard</code>
+  with <a href="#dfn-propertyuri" class="internalDFN"><code>propertyURI</code></a> set to <code>vocabulary</code>,
+  it generates these triples expressed in Turtle:</p>
+
+<div class="example"><div class="example-title"><span>Example 19</span></div><pre class="example">@prefix md: &lt;http://www.w3.org/ns/md#&gt; .
[email protected] hcard: &lt;http://microformats.org/profile/hcard#&gt; .
[email protected] rdfa: &lt;http://www.w3.org/ns/rdfa#&gt; .
+
+&lt;&gt; md:item (
+  [ a &lt;http://microformats.org/profile/hcard&gt;;
+    hcard:fn &quot;Princeton&quot;;
+    hcard:n [ hcard:given-name &quot;Princeton&quot; ];
+    hcard:adr _:a
+  ]
+  [ a &lt;http://microformats.org/profile/hcard&gt;;
+    hcard:fn &quot;Trekkie&quot;;
+    hcard:n [ hcard:given-name &quot;Trekkie&quot; ];
+    hcard:adr _:a
+  ]) ;
+  rdfa:usesVocabulary &lt;http://microformats.org/profile/hcard&gt; .
+
+_:a hcard:street-address &quot;Avenue Q&quot; .</pre></div>
+
+<p>The following snippet of HTML has microdata for a playlist, and illustrates overriding a property
+  to place elements in an RDF Collection. This also illustrates the use of the <code>schema:additionalType</code>
+  property to relate recordings to the <cite><a href="http://musicontology.com/">Music Ontology</a></cite>:</p>
+<div class="example"><div class="example-title"><span>Example 20</span></div><pre class="example">&lt;div itemscope itemtype=&quot;http://schema.org/MusicPlaylist&quot;&gt;
+  &lt;span itemprop=&quot;name&quot;&gt;Classic Rock Playlist&lt;/span&gt;
+  &lt;meta itemprop=&quot;numTracks&quot; content=&quot;2&quot;/&gt;
+  &lt;p&gt;Including works by
+    &lt;span itemprop=&quot;byArtist&quot;&gt;Lynard Skynard&lt;/span&gt; and
+    &lt;span itemprop=&quot;byArtist&quot;&gt;AC/DC&lt;/span&gt;&lt;/p&gt;.
+
+  &lt;div itemprop=&quot;tracks&quot; itemscope itemtype=&quot;http://schema.org/MusicRecording&quot;&gt;
+    &lt;link itemprop=&quot;additionalType&quot; href=&quot;http://purl.org/ontology/mo/MusicalManifestation&quot;/&gt;
+    1.&lt;span itemprop=&quot;name&quot;&gt;Sweet Home Alabama&lt;/span&gt; -
+    &lt;span itemprop=&quot;byArtist&quot;&gt;Lynard Skynard&lt;/span&gt;
+    &lt;link href=&quot;sweet-home-alabama&quot; itemprop=&quot;url&quot; /&gt;
+   &lt;/div&gt;
+
+  &lt;div itemprop=&quot;tracks&quot; itemscope itemtype=&quot;http://schema.org/MusicRecording&quot;&gt;
+    &lt;link itemprop=&quot;additionalType&quot; href=&quot;http://purl.org/ontology/mo/MusicalManifestation&quot;/&gt;
+    2.&lt;span itemprop=&quot;name&quot;&gt;Shook you all Night Long&lt;/span&gt; -
+    &lt;span itemprop=&quot;byArtist&quot;&gt;AC/DC&lt;/span&gt;
+    &lt;link href=&quot;shook-you-all-night-long&quot; itemprop=&quot;url&quot; /&gt;
+  &lt;/div&gt;
+&lt;/div&gt;</pre></div>
+
+<p>Assuming that <a href="#dfn-registry" class="internalDFN">registry</a> contains a an entry for <code>http://schema.org/</code>
+  with <a href="#dfn-propertyuri" class="internalDFN"><code>propertyURI</code></a> set to <code>vocabulary</code>,
+  <a href="#dfn-multiplevalues" class="internalDFN"><code>multipleValues</code></a> set to <code>unordered</code> with the properties
+  <code>track</code> and <code>byArtist</code> having <a href="#dfn-multiplevalues" class="internalDFN"><code>multipleValues</code></a> set to <code>list</code>,
+  it generates these triples expressed in Turtle:</p>
+
+<div class="example"><div class="example-title"><span>Example 21</span></div><pre class="example">@prefix md: &lt;http://www.w3.org/ns/md#&gt; .
[email protected] mo: &lt;http://purl.org/ontology/mo/&gt; .
[email protected] rdf: &lt;http://www.w3.org/1999/02/22-rdf-syntax-ns#&gt; .
[email protected] rdfa: &lt;http://www.w3.org/ns/rdfa#&gt; .
[email protected] schema: &lt;http://schema.org/&gt; .
+
+&lt;&gt; md:item ([ a schema:MusicPlaylist;
+  schema:name &quot;Classic Rock Playlist&quot;;
+  schema:byArtist (&quot;Lynard Skynard&quot; &quot;AC/DC&quot;);
+  schema:numTracks &quot;2&quot;;
+  schema:tracks (
+    [ a schema:MusicRecording, mo:MusicalManifestation;
+      schema:additionalType mo:MusicalManifestation;
+      schema:byArtist (&quot;Lynard Skynard&quot;);
+      schema:name &quot;Sweet Home Alabama&quot;;
+      schema:url &lt;sweet-home-alabama&gt;]
+    [ a schema:MusicRecording, mo:MusicalManifestation;
+      schema:additionalType mo:MusicalManifestation;
+      schema:byArtist (&quot;AC/DC&quot;);;
+      schema:name &quot;Shook you all Night Long&quot;;
+      schema:url &lt;shook-you-all-night-long&gt;]
+  )]);
+  rdfa:usesVocabulary schema: .
+  
+schema:additionalType rdfs:subPropertyOf rdf:type .</pre></div>
+
+</section>
+
+<section class="appendix informative" id="example-registry">
+  
+<!--OddPage-->
+<h2><span class="secno">C. </span>Example <a href="#dfn-registry" class="internalDFN">registry</a></h2><p><em>This section is non-normative.</em></p>
+  <p>The following is an example <a href="#dfn-registry" class="internalDFN">registry</a> in JSON format.</p>
+
+  <div class="example"><div class="example-title"><span>Example 22</span></div><pre class="example">{
+  &quot;http://schema.org/&quot;: {
+    &quot;propertyURI&quot;:    &quot;vocabulary&quot;,
+    &quot;multipleValues&quot;: &quot;unordered&quot;,
+    &quot;properties&quot;: {
+      &quot;additionalType&quot;: {&quot;subPropertyOf&quot;: &quot;http://www.w3.org/1999/02/22-rdf-syntax-ns#type&quot;},
+      &quot;blogPosts&quot;: {&quot;multipleValues&quot;: &quot;list&quot;},
+      &quot;blogPosts&quot;: {&quot;multipleValues&quot;: &quot;list&quot;},
+      &quot;breadcrumb&quot;: {&quot;multipleValues&quot;: &quot;list&quot;},
+      &quot;byArtist&quot;: {&quot;multipleValues&quot;: &quot;list&quot;},
+      &quot;creator&quot;: {&quot;multipleValues&quot;: &quot;list&quot;},
+      &quot;episode&quot;: {&quot;multipleValues&quot;: &quot;list&quot;},
+      &quot;episodes&quot;: {&quot;multipleValues&quot;: &quot;list&quot;},
+      &quot;event&quot;: {&quot;multipleValues&quot;: &quot;list&quot;},
+      &quot;events&quot;: {&quot;multipleValues&quot;: &quot;list&quot;},
+      &quot;founder&quot;: {&quot;multipleValues&quot;: &quot;list&quot;},
+      &quot;founders&quot;: {&quot;multipleValues&quot;: &quot;list&quot;},
+      &quot;itemListElement&quot;: {&quot;multipleValues&quot;: &quot;list&quot;},
+      &quot;musicGroupMember&quot;: {&quot;multipleValues&quot;: &quot;list&quot;},
+      &quot;performerIn&quot;: {&quot;multipleValues&quot;: &quot;list&quot;},
+      &quot;actor&quot;: {&quot;multipleValues&quot;: &quot;list&quot;},
+      &quot;actors&quot;: {&quot;multipleValues&quot;: &quot;list&quot;},
+      &quot;performer&quot;: {&quot;multipleValues&quot;: &quot;list&quot;},
+      &quot;performers&quot;: {&quot;multipleValues&quot;: &quot;list&quot;},
+      &quot;producer&quot;: {&quot;multipleValues&quot;: &quot;list&quot;},
+      &quot;recipeInstructions&quot;: {&quot;multipleValues&quot;: &quot;list&quot;},
+      &quot;season&quot;: {&quot;multipleValues&quot;: &quot;list&quot;},
+      &quot;seasons&quot;: {&quot;multipleValues&quot;: &quot;list&quot;},
+      &quot;subEvent&quot;: {&quot;multipleValues&quot;: &quot;list&quot;},
+      &quot;subEvents&quot;: {&quot;multipleValues&quot;: &quot;list&quot;},
+      &quot;track&quot;: {&quot;multipleValues&quot;: &quot;list&quot;},
+      &quot;tracks&quot;: {&quot;multipleValues&quot;: &quot;list&quot;}
+    }
+  },
+  &quot;http://microformats.org/profile/hcard&quot;: {
+    &quot;propertyURI&quot;:    &quot;vocabulary&quot;,
+    &quot;multipleValues&quot;: &quot;unordered&quot;
+  },
+  &quot;http://microformats.org/profile/hcalendar#&quot;: {
+    &quot;propertyURI&quot;:    &quot;vocabulary&quot;,
+    &quot;multipleValues&quot;: &quot;unordered&quot;,
+    &quot;properties&quot;: {
+      &quot;categories&quot;: {&quot;multipleValues&quot;: &quot;list&quot;}
+    }
+  }
+}</pre></div>
+</section>
+
+<section class="appendix informative" id="acknowledgements">
+  
+<!--OddPage-->
+<h2><span class="secno">D. </span>Acknowledgements</h2><p><em>This section is non-normative.</em></p>
+  <p>Thanks to Richard Cyganiak for property URI and vocabulary terminology and the general excellent
+    consideration of practical problems in generating RDF from microdata.</p>
+</section>
+
+
+
+<section id="references" class="appendix">
+<!--OddPage-->
+<h2><span class="secno">E. </span>References</h2><section id="normative-references"><h3><span class="secno">E.1 </span>Normative references</h3><dl class="bibliography"><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-MICRODATA">[MICRODATA]</dt><dd><cite><a href="http://www.w3.org/TR/2012/WD-microdata-20120329/">HTML Microdata</a></cite> Ian Hickson Editor. W3C Working Draft. (Work in progress). 29 March 2012. This edition of the HTML Microdata specification is http://www.w3.org/TR/2012/WD-microdata-20120329/. The <a href="http://www.w3.org/TR/microdata/">latest edition of HTML Microdata</a> is available at http://www.w3.org/TR/microdata/
+</dd><dt id="bib-OWL2-OVERVIEW">[OWL2-OVERVIEW]</dt><dd>W3C OWL Working Group. <a href="http://www.w3.org/TR/2009/REC-owl2-overview-20091027/"><cite>OWL 2 Web Ontology Language: Overview.</cite></a> 27 October 2009. W3C Recommendation. URL: <a href="http://www.w3.org/TR/2009/REC-owl2-overview-20091027/">http://www.w3.org/TR/2009/REC-owl2-overview-20091027/</a> 
+</dd><dt id="bib-OWL2-PROFILES">[OWL2-PROFILES]</dt><dd>Boris Motik; Bernardo Cuenca Grau; Ian Horrocks; Zhe Wu; Achille Fokoue; Carsten Lutz. <a href="http://www.w3.org/TR/2009/REC-owl2-profiles-20091027/"><cite>OWL 2 Web Ontology Language:Profiles.</cite></a> 27 October 2009. W3C Recommendation. URL: <a href="http://www.w3.org/TR/2009/REC-owl2-profiles-20091027/">http://www.w3.org/TR/2009/REC-owl2-profiles-20091027/</a> 
+</dd><dt id="bib-OWL2-RDF-BASED-SEMANTICS">[OWL2-RDF-BASED-SEMANTICS]</dt><dd>Michael Schneider. <a href="http://www.w3.org/TR/2009/REC-owl2-rdf-based-semantics-20091027/"><cite>OWL 2 Web Ontology Language:RDF-Based Semantics.</cite></a> 27 October 2009. W3C Recommendation. URL: <a href="http://www.w3.org/TR/2009/REC-owl2-rdf-based-semantics-20091027/">http://www.w3.org/TR/2009/REC-owl2-rdf-based-semantics-20091027/</a> 
+</dd><dt id="bib-RDF-CONCEPTS">[RDF-CONCEPTS]</dt><dd>Graham Klyne; Jeremy J. Carroll. <a href="http://www.w3.org/TR/2004/REC-rdf-concepts-20040210"><cite>Resource Description Framework (RDF): Concepts and Abstract Syntax.</cite></a> 10 February 2004. W3C Recommendation. URL: <a href="http://www.w3.org/TR/2004/REC-rdf-concepts-20040210">http://www.w3.org/TR/2004/REC-rdf-concepts-20040210</a> 
+</dd><dt id="bib-RDF-MT">[RDF-MT]</dt><dd>Patrick Hayes. <a href="http://www.w3.org/TR/2004/REC-rdf-mt-20040210"><cite>RDF Semantics.</cite></a> 10 February 2004. W3C Recommendation. URL: <a href="http://www.w3.org/TR/2004/REC-rdf-mt-20040210">http://www.w3.org/TR/2004/REC-rdf-mt-20040210</a> 
+</dd><dt id="bib-RDF-SCHEMA">[RDF-SCHEMA]</dt><dd>Dan Brickley; Ramanathan V. Guha. <a href="http://www.w3.org/TR/2004/REC-rdf-schema-20040210"><cite>RDF Vocabulary Description Language 1.0: RDF Schema.</cite></a> 10 February 2004. W3C Recommendation. URL: <a href="http://www.w3.org/TR/2004/REC-rdf-schema-20040210">http://www.w3.org/TR/2004/REC-rdf-schema-20040210</a> 
+</dd><dt id="bib-RFC3986">[RFC3986]</dt><dd>T. Berners-Lee; R. Fielding; L. Masinter. <a href="http://www.ietf.org/rfc/rfc3986.txt"><cite>Uniform Resource Identifier (URI): Generic Syntax.</cite></a> January 2005. Internet RFC 3986. URL: <a href="http://www.ietf.org/rfc/rfc3986.txt">http://www.ietf.org/rfc/rfc3986.txt</a> 
+</dd></dl></section><section id="informative-references"><h3><span class="secno">E.2 </span>Informative references</h3><dl class="bibliography"><dt id="bib-MICRODATA-RDF-SUPPLEMENT">[MICRODATA-RDF-SUPPLEMENT]</dt><dd><cite><a href="http://dvcs.w3.org/hg/htmldata/raw-file/default/microdata-supplement/index.html">Microdata to RDF Supplement</a></cite> Gregg Kellogg Editor. World Wide Web Consortium (work in progress). 22 January 2012.
+</dd><dt id="bib-MICRODATA-RDF-TESTS">[MICRODATA-RDF-TESTS]</dt><dd><cite><a href="http://dvcs.w3.org/hg/htmldata/raw-file/default/microdata-rdf/tests/index.html">Microdata to RDF Tests</a></cite> Gregg Kellogg, Ivan Herman Editors. World Wide Web Consortium (work in progress). 22 March 2012.
+</dd><dt id="bib-RDF-SYNTAX-GRAMMAR">[RDF-SYNTAX-GRAMMAR]</dt><dd>Dave Beckett. <a href="http://www.w3.org/TR/2004/REC-rdf-syntax-grammar-20040210"><cite>RDF/XML Syntax Specification (Revised).</cite></a> 10 February 2004. W3C Recommendation. URL: <a href="http://www.w3.org/TR/2004/REC-rdf-syntax-grammar-20040210">http://www.w3.org/TR/2004/REC-rdf-syntax-grammar-20040210</a> 
+</dd><dt id="bib-RDFA-CORE">[RDFA-CORE]</dt><dd>Shane McCarron; et al. <a href="http://www.w3.org/TR/2012/REC-rdfa-core-20120607/"><cite>RDFa Core 1.1: Syntax and processing rules for embedding RDF through attributes.</cite></a> 7 June 2012. W3C Recommendation. URL: <a href="http://www.w3.org/TR/2012/REC-rdfa-core-20120607/">http://www.w3.org/TR/2012/REC-rdfa-core-20120607/</a> 
+</dd></dl></section></section></body></html>
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