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<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01//EN"><html lang="en-US-x-Hixie"><title>HTML Microdata</title><style type="text/css">
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   <p><a href="http://www.w3.org/"><img alt="W3C" height="48" src="http://www.w3.org/Icons/w3c_home" width="72"></a></p>

   <h1>HTML Microdata</h1>
   <h2 class="no-num no-toc" id="generatedID"></h2>
   <h2 class="no-num no-toc" id="w3c-working-draft-25-may-2011">W3C Working Draft 25 May 2011</h2>
   <dl><dt>This Version:</dt>
    <dd><a href="http://www.w3.org/TR/2011/WD-microdata-20110525/">http://www.w3.org/TR/2011/WD-microdata-20110525/</a></dd>
    <dt>Latest Published Version:</dt>
    <dd><a href="http://www.w3.org/TR/microdata/">http://www.w3.org/TR/microdata/</a></dd>
    <dt>Latest Editor's Draft:</dt>
    <dd><a class="latest-link" href="http://dev.w3.org/html5/md/Overview.html">http://dev.w3.org/html5/md/Overview.html</a></dd>

    <dt>Previous Versions:</dt>
    <dd><a href="http://www.w3.org/TR/2011/WD-microdata-20110405/">http://www.w3.org/TR/2011/WD-microdata-20110405/</a></dd>
    <dd><a href="http://www.w3.org/TR/2011/WD-microdata-20110113/">http://www.w3.org/TR/2011/WD-microdata-20110113/</a></dd>
    <dd><a href="http://www.w3.org/TR/2010/WD-microdata-20101019/">http://www.w3.org/TR/2010/WD-microdata-20101019/</a></dd>
    <dd><a href="http://www.w3.org/TR/2010/WD-microdata-20100624/">http://www.w3.org/TR/2010/WD-microdata-20100624/</a></dd>
    <dd><a href="http://www.w3.org/TR/2010/WD-microdata-20100304/">http://www.w3.org/TR/2010/WD-microdata-20100304/</a></dd>
    <dd><a href="http://www.w3.org/TR/2009/WD-html5-20090825/">http://www.w3.org/TR/2009/WD-html5-20090825/</a></dd>
<!-- :ZZZ -->
    <dt>Editor:</dt>
    <dd><a href="mailto:ian@hixie.ch">Ian Hickson</a>, Google, Inc.</dd>
   </dl><p class="copyright"><a href="http://www.w3.org/Consortium/Legal/ipr-notice#Copyright">Copyright</a>
   &copy; 2011 <a href="http://www.w3.org/"><abbr title="World Wide
   Web Consortium">W3C</abbr></a><sup>&reg;</sup> (<a href="http://www.csail.mit.edu/"><abbr title="Massachusetts
   Institute of Technology">MIT</abbr></a>, <a href="http://www.ercim.org/"><abbr title="European Research
   Consortium for Informatics and Mathematics">ERCIM</abbr></a>, <a href="http://www.keio.ac.jp/">Keio</a>), All Rights Reserved. W3C
   <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>


   <!-- UNDER NO CIRCUMSTANCES IS THE FOLLOWING PARAGRAPH TO BE REMOVED OR EDITED WITHOUT TALKING TO IAN FIRST -->
   <p class="alt">The bulk of the text of this specification is also
   available in the WHATWG <a href="http://www.whatwg.org/specs/web-apps/current-work/complete.html#microdata">Web Applications 1.0</a> specification, under a license that permits
   reuse of the specification text.</p>
   <!-- UNDER NO CIRCUMSTANCES IS THE PRECEDING PARAGRAPH TO BE REMOVED OR EDITED WITHOUT TALKING TO IAN FIRST -->


  </div><hr class="top"><h2 class="no-num no-toc" id="abstract">Abstract</h2><p>This specification defines the HTML microdata mechanism. This
  mechanism allows machine-readable data to be embedded in HTML
  documents in an easy-to-write manner, with an unambiguous parsing
  model. It is compatible with numerous other data formats including
  RDF and JSON.<h2 class="no-num no-toc" id="status-of-this-document">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 W3C publications and the most recently
  formally published revision of this technical report can be found in
  the <a href="http://www.w3.org/TR/">W3C technical reports index</a>
  at http://www.w3.org/TR/.</em></p><p>If you wish to make comments regarding this document in a manner
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  mailing lists and take part in the discussions.<div id="multipage-common">


  <p class="stability" id="wip"><strong>This is a work in
  progress!</strong> For the latest updates from the HTML WG, possibly
  including important bug fixes, please look at the <a href="http://dev.w3.org/html5/md/Overview.html">editor's draft</a> instead.
  There may also be a more
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 with changes based on resolution of Last Call issues.
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<p>The W3C Technical Architecture Group has sent the HTML Working Group a
<a href="http://lists.w3.org/Archives/Public/public-html/2011May/0336.html">note regarding a technical issue in this document</a>;
there is also a related bug open:
<a href="http://www.w3.org/Bugs/Public/show_bug.cgi?id=12713">12713 (Mapping microdata in RDF)</a>.</p>

<p>W3C anticipates that there will be changes to this specification as a
result of the resolution of Last Call issues. Per the usual W3C Process,
any significant changes to the specification will trigger a subsequent Last
Call.</p>

<!-- UNDER NO CIRCUMSTANCES IS THE FOLLOWING PARAGRAPH TO BE REMOVED OR EDITED WITHOUT TALKING TO IAN FIRST -->
<p>The latest stable version of the editor's draft of this
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  HTML specifications:<dl><dt>E-mail notifications of changes</dt>
   <dd>HTML-Diffs mailing list (diff-marked HTML versions for each change): <a href="http://lists.w3.org/Archives/Public/public-html-diffs/latest">http://lists.w3.org/Archives/Public/public-html-diffs/latest</a></dd>
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  </dl><!-- UNDER NO CIRCUMSTANCES IS THE PRECEDING LIST TO BE REMOVED OR EDITED WITHOUT TALKING TO IAN FIRST --><p>The W3C <a href="http://www.w3.org/html/wg/">HTML Working
  Group</a> is the W3C working group responsible for this
  specification's progress along the W3C Recommendation
  track.
  This specification is the 25 May 2011 Last Call Working Draft.
  The Last Call period ends 03 August 2011.
  </p><!-- UNDER NO CIRCUMSTANCES IS THE PRECEDING PARAGRAPH TO BE REMOVED OR EDITED WITHOUT TALKING TO IAN FIRST --><p>Work on this specification is also done at the <a href="http://www.whatwg.org/">WHATWG</a>. The W3C HTML working group
  actively pursues convergence with the WHATWG, as required by the <a href="http://www.w3.org/2007/03/HTML-WG-charter">W3C HTML working
  group charter</a>.</p><!-- UNDER NO CIRCUMSTANCES IS THE FOLLOWING PARAGRAPH TO BE REMOVED OR EDITED WITHOUT TALKING TO IAN FIRST --><p>This document was produced by a group operating under the <a href="http://www.w3.org/Consortium/Patent-Policy-20040205/">5
  February 2004 W3C Patent Policy</a>. W3C maintains a <a href="http://www.w3.org/2004/01/pp-impl/40318/status" rel="disclosure">public list of
  any patent disclosures</a> made in connection with the deliverables
  of the group; that page also includes instructions for disclosing a
  patent. An individual who has actual knowledge of a patent which the
  individual believes contains <a href="http://www.w3.org/Consortium/Patent-Policy-20040205/#def-essential">Essential
  Claim(s)</a> must disclose the information in accordance with <a href="http://www.w3.org/Consortium/Patent-Policy-20040205/#sec-Disclosure">section
  6 of the W3C Patent Policy</a>.<h2 class="no-num no-toc" id="contents">Table of Contents</h2>
<ol class="toc">
 <li><a href="#common-infrastructure"><span class="secno">1 </span>Common infrastructure</a>
  <ol>
   <li><a href="#conformance-requirements"><span class="secno">1.1 </span>Conformance requirements</a></li>
   <li><a href="#htmlpropertiescollection-0"><span class="secno">1.2 </span>HTMLPropertiesCollection</a></ol></li>
 <li><a href="#introduction"><span class="secno">2 </span>Introduction</a>
  <ol>
   <li><a href="#overview"><span class="secno">2.1 </span>Overview</a></li>
   <li><a href="#the-basic-syntax"><span class="secno">2.2 </span>The basic syntax</a></li>
   <li><a href="#typed-items"><span class="secno">2.3 </span>Typed items</a></li>
   <li><a href="#global-identifiers-for-items"><span class="secno">2.4 </span>Global identifiers for items</a></li>
   <li><a href="#selecting-names-when-defining-vocabularies"><span class="secno">2.5 </span>Selecting names when defining vocabularies</a></li>
   <li><a href="#using-the-microdata-dom-api"><span class="secno">2.6 </span>Using the microdata DOM API</a></ol></li>
 <li><a href="#encoding-microdata"><span class="secno">3 </span>Encoding microdata</a>
  <ol>
   <li><a href="#the-microdata-model"><span class="secno">3.1 </span>The microdata model</a></li>
   <li><a href="#items"><span class="secno">3.2 </span>Items</a></li>
   <li><a href="#names:-the-itemprop-attribute"><span class="secno">3.3 </span>Names: the <code>itemprop</code> attribute</a></li>
   <li><a href="#values"><span class="secno">3.4 </span>Values</a></li>
   <li><a href="#associating-names-with-items"><span class="secno">3.5 </span>Associating names with items</a></ol></li>
 <li><a href="#microdata-dom-api"><span class="secno">4 </span>Microdata DOM API</a>
  <ol>
   <li><a href="#drag-and-drop"><span class="secno">4.1 </span>Drag-and-drop</a></ol></li>
 <li><a href="#converting-html-to-other-formats"><span class="secno">5 </span>Converting HTML to other formats</a>
  <ol>
   <li><a href="#json"><span class="secno">5.1 </span>JSON</a></li>
   <li><a href="#rdf"><span class="secno">5.2 </span>RDF</a>
    <ol>
     <li><a href="#examples"><span class="secno">5.2.1 </span>Examples</a></ol></ol></li>
 <li><a href="#iana"><span class="secno">6 </span>IANA considerations</a>
  <ol>
   <li><a href="#application-microdata-json"><span class="secno">6.1 </span><code>application/microdata+json</code></a></ol></li>
 <li><a class="no-num" href="#references">References</a></li>
 <li><a class="no-num" href="#acknowledgements">Acknowledgements</a></ol>
<hr><h2 id="common-infrastructure"><span class="secno">1 </span>Common infrastructure</h2><p>This specification is designed to be used with a <dfn id="host-language">host
  language</dfn> that defines the following terms:<ul class="brief"><li>DOM <dfn id="collections">collections</dfn>
   <li>The <dfn id="htmlcollection-interface"><code>HTMLCollection</code> interface</dfn>
   <li><dfn id="reflect" title="reflect">Reflection</dfn> of IDL attributes
   <li><dfn id="tree-order">Tree order</dfn> in a DOM tree
   <li>A node's <dfn id="home-subtree">home subtree</dfn>
   <li><dfn id="url">URL</dfn>
   <li><dfn id="valid-url">Valid URL</dfn>
   <li><dfn id="absolute-url">Absolute URL</dfn>
   <li><dfn id="resolve-a-url">Resolve a URL</dfn>.
   <li><dfn id="alphanumeric-ascii-characters">Alphanumeric ASCII characters</dfn>
   <li><dfn id="space-characters">Space characters</dfn>
   <li><dfn id="split-a-string-on-spaces">Split a string on spaces</dfn>
   <li><dfn id="converted-to-ascii-uppercase">Converted to ASCII uppercase</dfn>
   <li><dfn id="prefix-match">Prefix match</dfn>
   <li><dfn id="html-elements">HTML elements</dfn>
   <li>The <dfn id="htmlelement"><code>HTMLElement</code></dfn> interface
   <li>The <dfn id="htmldocument"><code>HTMLDocument</code></dfn> interface
   <li><dfn id="the-title-element">The <code>title</code> element</dfn> in the context of an <code><a href="#htmldocument">HTMLDocument</a></code>
   <li><dfn id="flow-content">Flow content</dfn>
   <li><dfn id="phrasing-content">Phrasing content</dfn>
   <li>An element's <dfn id="concept-id" title="concept-ID">ID</dfn>
   <li>An element's <dfn id="language">language</dfn>
   <li>A set of <dfn id="global-attributes">global attributes</dfn>
   <li><dfn id="boolean-attribute">Boolean attribute</dfn>
   <li><dfn id="unordered-set-of-unique-space-separated-tokens">Unordered set of unique space-separated tokens</dfn>
   <li><dfn id="valid-non-negative-integer">Valid non-negative integer</dfn>
   <li><dfn id="concept-date" title="concept-date">Date</dfn>
   <li><dfn id="concept-time" title="concept-time">Time</dfn>
   <li><dfn id="concept-datetime" title="concept-datetime">Global date and time</dfn>
   <li><dfn id="valid-date-string">Valid date string</dfn>
   <li><dfn id="valid-global-date-and-time-string">Valid global date and time string</dfn>
   <li><dfn id="the-document-s-current-address">The document's current address</dfn>
   <li><dfn id="drag-and-drop-initialization-steps">Drag-and-drop initialization steps</dfn>
   <li>The <dfn id="list-of-dragged-nodes">list of dragged  nodes</dfn>
  </ul><p>The <a href="#host-language">host language</a> also defines the elements used in
  this specification.</p><h3 id="conformance-requirements"><span class="secno">1.1 </span>Conformance requirements</h3><p>All diagrams, examples, and notes in this specification are
  non-normative, as are all sections explicitly marked non-normative.
  Everything else in this specification is normative.<p>The key words "MUST", "MUST NOT", "REQUIRED",  "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and
  "OPTIONAL" in the normative parts of this document are to be
  interpreted as described in RFC2119. For readability, these words do
  not appear in all uppercase letters in this specification. <a href="#refsRFC2119">[RFC2119]</a><div class="impl">

  <p>Requirements phrased in the imperative as part of algorithms
  (such as "strip any leading space characters" or "return false and
  abort these steps") are to be interpreted with the meaning of the
  key word ("must", "should", "may", etc) used in introducing the
  algorithm.</p>

  <p>Conformance requirements phrased as algorithms or specific steps
  may be implemented in any manner, so long as the end result is
  equivalent. (In particular, the algorithms defined in this
  specification are intended to be easy to follow, and not intended to
  be performant.)</p>

  </div><h3 id="htmlpropertiescollection-0"><span class="secno">1.2 </span>HTMLPropertiesCollection</h3><p>The <code><a href="#htmlpropertiescollection">HTMLPropertiesCollection</a></code> interface represents a
  <a href="#collections" title="collections">collection</a> of elements that add
  name-value pairs to a particular <a href="#concept-item" title="concept-item">item</a> in the <span>microdata</span>
  model.<pre class="idl">interface <dfn id="htmlpropertiescollection">HTMLPropertiesCollection</dfn> : <span>HTMLCollection</span> {
  // inherits <span title="dom-HTMLCollection-length">length</span> and <span title="dom-HTMLCollection-item">item</span>()
  caller getter <a href="#propertynodelist">PropertyNodeList</a> <a href="#dom-htmlpropertiescollection-nameditem" title="dom-HTMLPropertiesCollection-namedItem">namedItem</a>(in DOMString name); // overrides inherited namedItem()
  readonly attribute <span>DOMStringList</span> <a href="#dom-htmlpropertiescollection-names" title="dom-HTMLPropertiesCollection-names">names</a>;
};

typedef sequence&lt;any&gt; <dfn id="propertyvaluearray">PropertyValueArray</dfn>;

interface <dfn id="propertynodelist">PropertyNodeList</dfn> : <span>NodeList</span> {
  <a href="#propertyvaluearray">PropertyValueArray</a> <a href="#dom-propertynodelist-getvalues" title="dom-PropertyNodeList-getValues">getValues</a>();
};</pre><dl class="domintro"><dt><var title="">collection</var> . <code title="dom-HTMLCollection-length">length</code></dt>
   <dd>
    <p>Returns the number of elements in the collection.</p>
   </dd>

   <dt><var title="">element</var> = <var title="">collection</var> . <code title="dom-HTMLCollection-item">item</code>(<var title="">index</var>)</dt>
   <dt><var title="">collection</var>[<var title="">index</var>]</dt>
   <dt><var title="">collection</var>(<var title="">index</var>)</dt>
   <dd>
    <p>Returns the element with index <var title="">index</var> from the collection. The items are sorted in <a href="#tree-order">tree order</a>.</p>
    <p>Returns null if <var title="">index</var> is out of range.</p>
   </dd>

   <dt><var title="">propertyNodeList</var> = <var title="">collection</var> . <code title="dom-HTMLPropertiesCollection-namedItem"><a href="#dom-htmlpropertiescollection-nameditem">namedItem</a></code>(<var title="">name</var>)</dt>
   <dt><var title="">collection</var>[<var title="">name</var>]</dt>
   <dt><var title="">collection</var>(<var title="">name</var>)</dt>
   <dd>
    <p>Returns a <code><a href="#propertynodelist">PropertyNodeList</a></code> object containing any elements that add a property named <var title="">name</var>.</p>
   </dd>

   <dt><var title="">collection</var> . <code title="dom-HTMLPropertiesCollection-names"><a href="#dom-htmlpropertiescollection-names">names</a></code></dt>
   <dd>
    <p>Returns a <code>DOMStringList</code> with the <a href="#property-names">property names</a> of the elements in the collection.</p>
   </dd>

   <dt><var title="">propertyNodeList</var> . <code title="dom-PropertyNodeList-getVlues">getValues</code>()</dt>
   <dd>
    <p>Returns an array of the various values that the relevant elements have.</p>
   </dd>

  </dl><div class="impl">

  <p>The object's <span>supported property indices</span> are as
  defined for <code>HTMLCollection</code> objects.</p>

  <p>The <span>supported property names</span> consist of the
  <a href="#property-names">property names</a> of all the elements <span>represented by
  the collection</span>.</p>

  <p>The <dfn id="dom-htmlpropertiescollection-names" title="dom-HTMLPropertiesCollection-names"><code>names</code></dfn>
  attribute must return a <span>live</span> <code>DOMStringList</code>
  object giving the <a href="#property-names">property names</a> of all the elements
  <span>represented by the collection</span>, listed in <a href="#tree-order">tree
  order</a>, but with duplicates removed, leaving only the first
  occurrence of each name. The same object must be returned each
  time.</p>

  <p>The <dfn id="dom-htmlpropertiescollection-nameditem" title="dom-HTMLPropertiesCollection-namedItem"><code>namedItem(<var title="">name</var>)</code></dfn> method must return a
  <code><a href="#propertynodelist">PropertyNodeList</a></code> object representing a
  <span>live</span> view of the <code><a href="#htmlpropertiescollection">HTMLPropertiesCollection</a></code>
  object, further filtered so that the only nodes in the
  <code><a href="#propertynodelist">PropertyNodeList</a></code> object are those that have a <a href="#property-names" title="property names">property name</a> equal to <var title="">name</var>. The nodes in the <code><a href="#propertynodelist">PropertyNodeList</a></code>
  object must be sorted in <a href="#tree-order">tree order</a>, and the same
  object must be returned each time a particular <var title="">name</var> is queried.</p>

  <hr><p>Members of the <code><a href="#propertynodelist">PropertyNodeList</a></code> interface inherited
  from the <code>NodeList</code> interface must behave as they would
  on a <code>NodeList</code> object.</p>

  <p>The <dfn id="dom-propertynodelist-getvalues" title="dom-PropertyNodeList-getValues"><code>getValues</code></dfn>
  method the <code><a href="#propertynodelist">PropertyNodeList</a></code> object must return a newly
  constructed array whose values are the values obtained from the
  <code title="dom-itemValue"><a href="#dom-itemvalue">itemValue</a></code> DOM property of each of
  the elements represented by the object, in <a href="#tree-order">tree
  order</a>.</p>

  </div><h2 id="introduction"><span class="secno">2 </span>Introduction</h2><h3 id="overview"><span class="secno">2.1 </span>Overview</h3><p><i>This section is non-normative.</i><p>Sometimes, it is desirable to annotate content with specific
  machine-readable labels, e.g. to allow generic scripts to provide
  services that are customised to the page, or to enable content from
  a variety of cooperating authors to be processed by a single script
  in a consistent manner.<p>For this purpose, authors can use the microdata features
  described in this section. Microdata allows nested groups of
  name-value pairs to be added to documents, in parallel with the
  existing content.<h3 id="the-basic-syntax"><span class="secno">2.2 </span>The basic syntax</h3><p><i>This section is non-normative.</i><p>At a high level, microdata consists of a group of name-value
  pairs. The groups are called <a href="#concept-item" title="concept-item">items</a>, and each name-value pair is a
  property. Items and properties are represented by regular
  elements.<p>To create an item, the <code title="attr-itemscope"><a href="#attr-itemscope">itemscope</a></code> attribute is used.<p>To add a property to an item, the <code title="attr-itemprop"><a href="#names:-the-itemprop-attribute">itemprop</a></code> attribute is used on one of
  the <a href="#concept-item" title="concept-item">item's</a> descendants.<div class="example">

   <p>Here there are two items, each of which has the property "name":</p>

   <pre>&lt;div itemscope&gt;
 &lt;p&gt;My name is &lt;span itemprop="name"&gt;Elizabeth&lt;/span&gt;.&lt;/p&gt;
&lt;/div&gt;

&lt;div itemscope&gt;
 &lt;p&gt;My name is &lt;span itemprop="name"&gt;Daniel&lt;/span&gt;.&lt;/p&gt;
&lt;/div&gt;</pre>

  </div><p>Properties generally have values that are strings.<div class="example">

   <p>Here the item has three properties:</p>

   <pre>&lt;div itemscope&gt;
 &lt;p&gt;My name is &lt;span itemprop="name"&gt;Neil&lt;/span&gt;.&lt;/p&gt;
 &lt;p&gt;My band is called &lt;span itemprop="band"&gt;Four Parts Water&lt;/span&gt;.&lt;/p&gt;
 &lt;p&gt;I am &lt;span itemprop="nationality"&gt;British&lt;/span&gt;.&lt;/p&gt;
&lt;/div&gt;</pre>

  </div><p>Properties can also have values that are <a href="#url" title="URL">URLs</a>. This is achieved using the <code>a</code>
  element and its <code title="attr-hyperlink-href">href</code>
  attribute, the <code>img</code> element and its <code title="attr-img-src">src</code> attribute, or other elements that
  link to or embed external resources.<div class="example">

   <p>In this example, the item has one property, "image", whose value
   is a URL:</p>

   <pre>&lt;div itemscope&gt;
 &lt;img itemprop="image" src="google-logo.png" alt="Google"&gt;
&lt;/div&gt;</pre>

  </div><p>Properties can also have values that are dates, times, or dates
  and times. This is achieved using the <code>time</code> element and
  its <code title="attr-time-datetime">datetime</code> attribute.<div class="example">

   <p>In this example, the item has one property,
   "birthday", whose value is a date:</p>

   <pre>&lt;div itemscope&gt;
 I was born on &lt;time itemprop="birthday" datetime="2009-05-10"&gt;May 10th 2009&lt;/time&gt;.
&lt;/div&gt;</pre>

  </div><p>Properties can also themselves be groups of name-value pairs, by
  putting the <code title="attr-itemscope"><a href="#attr-itemscope">itemscope</a></code> attribute
  on the element that declares the property.<p>Items that are not part of others are called <a href="#top-level-microdata-items">top-level
  microdata items</a>.<div class="example">

   <p>In this example, the outer item represents a person, and the
   inner one represents a band:</p>

   <pre>&lt;div itemscope&gt;
 &lt;p&gt;Name: &lt;span itemprop="name"&gt;Amanda&lt;/span&gt;&lt;/p&gt;
 &lt;p&gt;Band: &lt;span itemprop="band" itemscope&gt; &lt;span itemprop="name"&gt;Jazz Band&lt;/span&gt; (&lt;span itemprop="size"&gt;12&lt;/span&gt; players)&lt;/span&gt;&lt;/p&gt;
&lt;/div&gt;</pre>

   <p>The outer item here has two properties, "name" and
   "band". The "name" is "Amanda", and the
   "band" is an item in its own right, with two
   properties, "name" and "size". The
   "name" of the band is "Jazz Band", and the
   "size" is "12".</p>

   <p>The outer item in this example is a top-level microdata
   item.</p>

  </div><p>Properties that are not descendants of the element with the <code title="attr-itemscope"><a href="#attr-itemscope">itemscope</a></code> attribute can be associated
  with the <a href="#concept-item" title="concept-item">item</a> using the <code title="attr-itemref"><a href="#attr-itemref">itemref</a></code> attribute. This attribute takes
  a list of IDs of elements to crawl in addition to crawling the
  children of the element with the <code title="attr-itemscope"><a href="#attr-itemscope">itemscope</a></code> attribute.<div class="example">

   <p>This example is the same as the previous one, but all the
   properties are separated from their <a href="#concept-item" title="concept-item">items</a>:</p>

   <pre>&lt;div itemscope id="amanda" itemref="a b"&gt;&lt;/div&gt;
&lt;p id="a"&gt;Name: &lt;span itemprop="name"&gt;Amanda&lt;/span&gt;&lt;/p&gt;
&lt;div id="b" itemprop="band" itemscope itemref="c"&gt;&lt;/div&gt;
&lt;div id="c"&gt;
 &lt;p&gt;Band: &lt;span itemprop="name"&gt;Jazz Band&lt;/span&gt;&lt;/p&gt;
 &lt;p&gt;Size: &lt;span itemprop="size"&gt;12&lt;/span&gt; players&lt;/p&gt;
&lt;/div&gt;</pre>

   <p>This gives the same result as the previous example. The first
   item has two properties, "name", set to "Amanda", and "band", set
   to another item. That second item has two further properties,
   "name", set to "Jazz Band", and "size", set to "12".</p>

  </div><p>An <a href="#concept-item" title="concept-item">item</a> can have multiple
  properties with the same name and different values.<div class="example">

   <p>This example describes an ice cream, with two flavors:</p>

   <pre>&lt;div itemscope&gt;
 &lt;p&gt;Flavors in my favorite ice cream:&lt;/p&gt;
 &lt;ul&gt;
  &lt;li itemprop="flavor"&gt;Lemon sorbet&lt;/li&gt;
  &lt;li itemprop="flavor"&gt;Apricot sorbet&lt;/li&gt;
 &lt;/ul&gt;
&lt;/div&gt;</pre>

   <p>This thus results in an item with two properties, both
   "flavor", having the values "Lemon sorbet" and "Apricot
   sorbet".</p>

  </div><p>An element introducing a property can also introduce multiple
  properties at once, to avoid duplication when some of the properties
  have the same value.<div class="example">

   <p>Here we see an item with two properties,
   "favorite-color" and "favorite-fruit", both
   set to the value "orange":</p>

   <pre>&lt;div itemscope&gt;
 &lt;span itemprop="favorite-color favorite-fruit"&gt;orange&lt;/span&gt;
&lt;/div&gt;</pre>

  </div><p>It's important to note that there is no relationship between the
  microdata and the content of the document where the microdata is
  marked up.<div class="example">

   <p>There is no semantic difference, for instance, between the
   following two examples:</p>

   <pre>&lt;figure&gt;
 &lt;img src="castle.jpeg"&gt;
 &lt;figcaption&gt;&lt;span itemscope&gt;&lt;span itemprop="name"&gt;The Castle&lt;/span&gt;&lt;/span&gt; (1986)&lt;/figcaption&gt;
&lt;/figure&gt;</pre>

   <pre>&lt;span itemscope&gt;&lt;meta itemprop="name" content="The Castle"&gt;&lt;/span&gt;
&lt;figure&gt;
 &lt;img src="castle.jpeg"&gt;
 &lt;figcaption&gt;The Castle (1986)&lt;/figcaption&gt;
&lt;/figure&gt;</pre>

   <p>Both have a figure with a caption, and both, completely
   unrelated to the figure, have an item with a name-value pair with
   the name "name" and the value "The Castle". The only
   difference is that if the user drags the caption out of the
   document, in the former case, the item will be included in the
   drag-and-drop data. In neither case is the image in any way
   associated with the item.</p>

  </div><h3 id="typed-items"><span class="secno">2.3 </span>Typed items</h3><p><i>This section is non-normative.</i><p>The examples in the previous section show how information could
  be marked up on a page that doesn't expect its microdata to be
  re-used. Microdata is most useful, though, when it is used in
  contexts where other authors and readers are able to cooperate to
  make new uses of the markup.<p>For this purpose, it is necessary to give each <a href="#concept-item" title="concept-item">item</a> a type, such as
  "http://example.com/person", or "http://example.org/cat", or
  "http://band.example.net/". Types are identified as <a href="#url" title="URL">URLs</a>.<p>The type for an <a href="#concept-item" title="concept-item">item</a> is given
  as the value of an <code title="attr-itemtype"><a href="#attr-itemtype">itemtype</a></code>
  attribute on the same element as the <code title="attr-itemscope"><a href="#attr-itemscope">itemscope</a></code> attribute.<div class="example">

   <p>Here, the item's type is "http://example.org/animals#cat":</p>

<pre>&lt;section itemscope itemtype="http://example.org/animals#cat"&gt;
 &lt;h1 itemprop="name"&gt;Hedral&lt;/h1&gt;
 &lt;p itemprop="desc"&gt;Hedral is a male american domestic
 shorthair, with a fluffy black fur with white paws and belly.&lt;/p&gt;
 &lt;img itemprop="img" src="hedral.jpeg" alt="" title="Hedral, age 18 months"&gt;
&lt;/section&gt;</pre>

   <p>In this example the "http://example.org/animals#cat" item has three
   properties, a "name" ("Hedral"), a "desc" ("Hedral is..."), and an
   "img" ("hedral.jpeg").</p>

  </div><p>An item can only have one type. The type gives the context for
  the properties, thus defining a vocabulary: a property named "class"
  given for an item with the type "http://census.example/person" might
  refer to the economic class of an individual, while a property named
  "class" given for an item with the type "http://example.com/school/teacher"
  might refer to the classroom a teacher has been assigned.<h3 id="global-identifiers-for-items"><span class="secno">2.4 </span>Global identifiers for items</h3><p><i>This section is non-normative.</i><p>Sometimes, an <a href="#concept-item" title="concept-item">item</a> gives
  information about a topic that has a global identifier. For example,
  books can be identified by their ISBN number.<p>Vocabularies (as identified by the <code title="attr-itemtype"><a href="#attr-itemtype">itemtype</a></code> attribute) can be designed
  such that <a href="#concept-item" title="concept-item">items</a> get associated
  with their global identifier in an unambiguous way by expressing the
  global identifiers as <a href="#url" title="URL">URLs</a> given in an
  <code title="attr-itemid"><a href="#attr-itemid">itemid</a></code> attribute.<p>The exact meaning of the <a href="#url" title="URL">URLs</a> given in
  <code title="attr-itemid"><a href="#attr-itemid">itemid</a></code> attributes depends on the
  vocabulary used.<div class="example">

   <p>Here, an item is talking about a particular book:</p>

<pre>&lt;dl itemscope
    itemtype="http://vocab.example.net/book"
    <strong>itemid="urn:isbn:0-330-34032-8"</strong>&gt;
 &lt;dt&gt;Title
 &lt;dd itemprop="title"&gt;The Reality Dysfunction
 &lt;dt&gt;Author
 &lt;dd itemprop="author"&gt;Peter F. Hamilton
 &lt;dt&gt;Publication date
 &lt;dd&gt;&lt;time itemprop="pubdate" datetime="1996-01-26"&gt;26 January 1996&lt;/time&gt;
&lt;/dl&gt;</pre>

   <p>The "<code title="">http://vocab.example.net/book</code>"
   vocabulary in this example would define that the <code title="attr-itemid"><a href="#attr-itemid">itemid</a></code> attribute takes a <code title="">urn:</code> <a href="#url">URL</a> pointing to the ISBN of the
   book.</p>

  </div><h3 id="selecting-names-when-defining-vocabularies"><span class="secno">2.5 </span>Selecting names when defining vocabularies</h3><p><i>This section is non-normative.</i><p>Using microdata means using a vocabulary. For some purposes, an
  ad-hoc vocabulary is adequate. For others, a vocabulary will need to
  be designed. Where possible, authors are encouraged to re-use
  existing vocabularies, as this makes content re-use easier.<p>When designing new vocabularies, identifiers can be created
  either using <a href="#url" title="URL">URLs</a>, or, for properties, as
  plain words (with no dots or colons). For URLs, conflicts with other
  vocabularies can be avoided by only using identifiers that
  correspond to pages that the author has control over.<div class="example">

   <p>For instance, if Jon and Adam both write content at <code title="">example.com</code>, at <code title="">http://example.com/~jon/...</code> and <code title="">http://example.com/~adam/...</code> respectively, then
   they could select identifiers of the form
   "http://example.com/~jon/name" and "http://example.com/~adam/name"
   respectively.</p>

  </div><p>Properties whose names are just plain words can only be used
  within the context of the types for which they are intended;
  properties named using URLs can be reused in items of any type. If
  an item has no type, and is not part of another item, then if its
  properties have names that are just plain words, they are not
  intended to be globally unique, and are instead only intended for
  limited use. Generally speaking, authors are encouraged to use
  either properties with globally unique names (URLs) or ensure that
  their items are typed.<div class="example">

   <p>Here, an item is an "http://example.org/animals#cat", and most of the
   properties have names that are words defined in the context of that
   type. There are also a few additional properties whose names come
   from other vocabularies.</p>

<pre>&lt;section itemscope itemtype="http://example.org/animals#cat"&gt;
 &lt;h1 itemprop="name http://example.com/fn"&gt;Hedral&lt;/h1&gt;
 &lt;p itemprop="desc"&gt;Hedral is a male american domestic
 shorthair, with a fluffy &lt;span
 itemprop="http://example.com/color"&gt;black&lt;/span&gt; fur with &lt;span
 itemprop="http://example.com/color"&gt;white&lt;/span&gt; paws and belly.&lt;/p&gt;
 &lt;img itemprop="img" src="hedral.jpeg" alt="" title="Hedral, age 18 months"&gt;
&lt;/section&gt;</pre>

   <p>This example has one item with the type "http://example.org/animals#cat"
   and the following properties:</p>

   <table><thead><tr><td>Property
      <td>Value
    <tbody><tr><td>name
      <td>Hedral
     <tr><td>http://example.com/fn
      <td>Hedral
     <tr><td>desc
      <td>Hedral is a male american domestic shorthair, with a fluffy black fur with white paws and belly.
     <tr><td>http://example.com/color
      <td>black
     <tr><td>http://example.com/color
      <td>white
     <tr><td>img
      <td>.../hedral.jpeg
   </table></div><h3 id="using-the-microdata-dom-api"><span class="secno">2.6 </span>Using the microdata DOM API</h3><p><i>This section is non-normative.</i><p>The microdata becomes even more useful when scripts can use it to
  expose information to the user, for example offering it in a form
  that can be used by other applications.<p>The <code title="dom-document-getItems"><a href="#dom-document-getitems">document.getItems(<var title="">typeNames</var>)</a></code> method provides access to the
  <a href="#top-level-microdata-items">top-level microdata items</a>. It returns a
  <code>NodeList</code> containing the items with the specified types,
  or all types if no argument is specified.<p>Each <a href="#concept-item" title="concept-item">item</a> is represented in the
  DOM by the element on which the relevant <code title="attr-itemscope"><a href="#attr-itemscope">itemscope</a></code> attribute is found. These
  elements have their <code title="dom-itemScope"><a href="#dom-itemscope">element.itemScope</a></code> IDL attribute set to
  true.<p>The type of <a href="#concept-item" title="concept-item">items</a> can be
  obtained using the <code title="dom-itemType"><a href="#dom-itemtype">element.itemType</a></code> IDL attribute on the
  element with the <code title="attr-itemscope"><a href="#attr-itemscope">itemscope</a></code>
  attribute.<div class="example">

   <p>This sample shows how the <code title="dom-document-getItems"><a href="#dom-document-getitems">getItems()</a></code> method can be used
   to obtain a list of all the top-level microdata items of one type
   given in the document:</p>

   <pre>var cats = document.getItems("http://example.com/feline");</pre>

  </div><p>Once an element representing an <a href="#concept-item" title="concept-item">item</a> has been obtained, its properties
  can be extracted using the <code title="dom-properties"><a href="#dom-properties">properties</a></code> IDL attribute. This
  attribute returns an <code><a href="#htmlpropertiescollection">HTMLPropertiesCollection</a></code>, which can
  be enumerated to go through each element that adds one or more
  properties to the item. It can also be indexed by name, which will
  return an object with a list of the elements that add properties
  with that name.<p>Each element that adds a property also has a <code title="dom-itemValue"><a href="#dom-itemvalue">itemValue</a></code> IDL attribute that returns
  its value.<div class="example">

   <p>This sample gets the first item of type "http://example.net/user" and
   then pops up an alert using the "name" property from
   that item.</p>

   <pre>var user = document.getItems('http://example.net/user')[0];
alert('Hello ' + user.properties['name'][0].content + '!');</pre>

  </div><p>The <code><a href="#htmlpropertiescollection">HTMLPropertiesCollection</a></code> object, when indexed by
  name in this way, actually returns a <code><a href="#propertynodelist">PropertyNodeList</a></code>
  object with all the matching properties. The
  <code><a href="#propertynodelist">PropertyNodeList</a></code> object can be used to obtain all the
  values at once using <em>its</em> <code title="dom-PropertyNodeList-getValues"><a href="#dom-propertynodelist-getvalues">getValues</a></code> method,
  which returns an array of all the values.<div class="example">

   <p>In an earlier example, a "http://example.org/animals#cat" item had two
   "http://example.com/color" values. This script looks up the first such
   item and then lists all its values.</p>

   <pre>var cat = document.getItems('http://example.org/animals#cat')[0];
var colors = cat.properties['http://example.com/color'].getValues();
var result;
if (colors.length == 0) {
  result = 'Color unknown.';
} else if (colors.length == 1) {
  result = 'Color: ' + colors[0];
} else {
  result = 'Colors:';
  for (var i = 0; i &lt; colors.length; i += 1)
    result += ' ' + colors[i];
}</pre>

  </div><p>It's also possible to get a list of all the <a href="#property-names">property
  names</a> using the object's <code title="dom-HTMLPropertiesCollection-names"><a href="#dom-htmlpropertiescollection-names">names</a></code> IDL
  attribute.<div class="example">

   <p>This example creates a big list with a nested list for each item
   on the page, each with of all the property names used in that
   item.</p>

   <pre>var outer = document.createElement('ul');
var items = document.getItems();
for (var item = 0; item &lt; items.length; item += 1) {
  var itemLi = document.createElement('li');
  var inner = document.createElement('ul');
  for (var name = 0; name &lt; items[item].properties.names.length; name += 1) {
    var propLi = document.createElement('li');
    propLi.appendChild(document.createTextNode(items[item].properties.names[name]));
    inner.appendChild(propLi);
  }
  itemLi.appendChild(inner);
  outer.appendChild(itemLi);
}
document.body.appendChild(outer);</pre>

   <p>If faced with the following from an earlier example:</p>

   <pre>&lt;section itemscope itemtype="http://example.org/animals#cat"&gt;
 &lt;h1 itemprop="name http://example.com/fn"&gt;Hedral&lt;/h1&gt;
 &lt;p itemprop="desc"&gt;Hedral is a male american domestic
 shorthair, with a fluffy &lt;span
 itemprop="http://example.com/color"&gt;black&lt;/span&gt; fur with &lt;span
 itemprop="http://example.com/color"&gt;white&lt;/span&gt; paws and belly.&lt;/p&gt;
 &lt;img itemprop="img" src="hedral.jpeg" alt="" title="Hedral, age 18 months"&gt;
&lt;/section&gt;</pre>

   <p>...it would result in the following output:</p>

   <ul><li>
     <ul><li>name</li>
      <li>http://example.com/fn</li>
      <li>desc</li>
      <li>http://example.com/color</li>
      <li>img</li>
     </ul></li>
   </ul><p>(The duplicate occurrence of "http://example.com/color" is not included
   in the list.)</p>

  </div><h2 id="encoding-microdata"><span class="secno">3 </span>Encoding microdata</h2><p>The following attributes are added as <a href="#global-attributes">global
  attributes</a> to <a href="#html-elements">HTML elements</a>:<ul class="brief"><li><code title="attr-itemid"><a href="#attr-itemid">itemid</a></code></li>
   <li><code title="attr-itemprop"><a href="#names:-the-itemprop-attribute">itemprop</a></code></li>
   <li><code title="attr-itemref"><a href="#attr-itemref">itemref</a></code></li>
   <li><code title="attr-itemscope"><a href="#attr-itemscope">itemscope</a></code></li>
   <li><code title="attr-itemtype"><a href="#attr-itemtype">itemtype</a></code></li>
  </ul><h3 id="the-microdata-model"><span class="secno">3.1 </span>The microdata model</h3><p>The microdata model consists of groups of name-value pairs known
  as <a href="#concept-item" title="concept-item">items</a>.<p>Each group is known as an <a href="#concept-item" title="concept-item">item</a>. Each <a href="#concept-item" title="concept-item">item</a> can have an <a href="#item-type">item type</a>,
  a <a href="#global-identifier">global identifier</a> (if the <a href="#item-type">item type</a>
  <a href="#support-global-identifiers-for-items" title="support global identifiers for items">supports global
  identifiers for its items</a>), and a list of name-value
  pairs. Each name in the name-value pair is known as a <a href="#the-properties-of-an-item" title="the properties of an item">property</a>, and each <a href="#the-properties-of-an-item" title="the properties of an item">property</a> has one or more
  <a href="#concept-property-value" title="concept-property-value">values</a>. Each <a href="#concept-property-value" title="concept-property-value">value</a> is either a string or itself a group of
  name-value pairs (an <a href="#concept-item" title="concept-item">item</a>).<p>An <a href="#concept-item" title="concept-item">item</a> is said to be a
  <dfn id="typed-item">typed item</dfn> when either it has an <a href="#item-type">item type</a>,
  or it is the <a href="#concept-property-value" title="concept-property-value">value</a> of a <a href="#the-properties-of-an-item" title="the properties of an
  item">property</a> of a <a href="#typed-item">typed item</a>. The
  <dfn id="relevant-type">relevant type</dfn> for a <a href="#typed-item">typed item</a> is the <a href="#concept-item" title="concept-item">item</a>'s <a href="#item-type">item type</a>, if it has
  one, or else is the <a href="#relevant-type">relevant type</a> of the <a href="#concept-item" title="concept-item">item</a> for which it is a <a href="#the-properties-of-an-item" title="the
  properties of an item">property</a>'s <a href="#concept-property-value" title="concept-property-value">value</a>.<h3 id="items"><span class="secno">3.2 </span>Items</h3><p>Every <a href="#html-elements" title="HTML elements">HTML element</a> may have an
  <dfn id="attr-itemscope" title="attr-itemscope"><code>itemscope</code></dfn> attribute
  specified. The <code title="attr-itemscope"><a href="#attr-itemscope">itemscope</a></code>
  attribute is a <a href="#boolean-attribute">boolean attribute</a>.<p>An element with the <code title="attr-itemscope"><a href="#attr-itemscope">itemscope</a></code>
  attribute specified creates a new <dfn id="concept-item" title="concept-item">item</dfn>, a group of name-value pairs.<hr><p>Elements with an <code title="attr-itemscope"><a href="#attr-itemscope">itemscope</a></code>
  attribute may have an <dfn id="attr-itemtype" title="attr-itemtype"><code>itemtype</code></dfn> attribute
  specified, to give the <a href="#item-type">item type</a> of the <a href="#concept-item" title="concept-item">item</a>.<p>The <code title="attr-itemtype"><a href="#attr-itemtype">itemtype</a></code> attribute, if
  specified, must have a value that is a <a href="#valid-url">valid URL</a> that
  is an <a href="#absolute-url">absolute URL</a> for which the string "<code title="">http://www.w3.org/1999/xhtml/microdata#</code>" is not a
  <a href="#prefix-match">prefix match</a>.</p><p>The <dfn id="item-type">item type</dfn> of an <a href="#concept-item" title="concept-item">item</a> is the value of its element's <code title="attr-itemtype"><a href="#attr-itemtype">itemtype</a></code> attribute, if it has one and
  its value is not the empty string. If the <code title="attr-itemtype"><a href="#attr-itemtype">itemtype</a></code> attribute is missing or its
  value is the empty string, the <a href="#concept-item" title="concept-item">item</a> is said to have no <a href="#item-type">item
  type</a>.<p>The <a href="#item-type">item type</a> must be a type defined in an <span title="other applicable specifications">applicable
  specification</span>.<div class="impl">

   <p>Except if otherwise specified by that specification, the
   <a href="#url">URL</a> given as the <a href="#item-type">item type</a> should not be
   automatically dereferenced.</p>

   <p class="note">A specification could define that its <a href="#item-type">item
   type</a> can be derefenced to provide the user with help
   information, for example. In fact, vocabulary authors are
   encouraged to provide useful information at the given
   <a href="#url">URL</a>.</p>

   <p><a href="#item-type" title="item type">Item types</a> are opaque
   identifiers, and user agents must not dereference unknown <a href="#item-type" title="item type">item types</a>, or otherwise deconstruct them,
   in order to determine how to process <a href="#concept-item" title="concept-item">items</a> that use them.</p>

  </div><p>The <code title="attr-itemtype"><a href="#attr-itemtype">itemtype</a></code> attribute must
  not be specified on elements that do not have an <code title="attr-itemscope"><a href="#attr-itemscope">itemscope</a></code> attribute specified.<hr><p>Elements with an <code title="attr-itemscope"><a href="#attr-itemscope">itemscope</a></code>
  attribute and an <code title="attr-itemtype"><a href="#attr-itemtype">itemtype</a></code>
  attribute that references a vocabulary that is defined to
  <dfn id="support-global-identifiers-for-items">support global identifiers for items</dfn> may also have an
  <dfn id="attr-itemid" title="attr-itemid"><code>itemid</code></dfn> attribute
  specified, to give a global identifier for the <a href="#concept-item" title="concept-item">item</a>, so that it can be related to other
  <a href="#concept-item" title="concept-item">items</a> on pages elsewhere on the
  Web.<p>The <code title="attr-itemid"><a href="#attr-itemid">itemid</a></code> attribute, if
  specified, must have a value that is a <span>valid URL potentially
  surrounded by spaces</span>.<p>The <dfn id="global-identifier">global identifier</dfn> of an <a href="#concept-item" title="concept-item">item</a> is the value of its element's <code title="attr-itemid"><a href="#attr-itemid">itemid</a></code> attribute, if it has one, <a href="#resolve-a-url" title="resolve a url">resolved</a> relative to the element on
  which the attribute is specified. If the <code title="attr-itemid"><a href="#attr-itemid">itemid</a></code> attribute is missing or if
  resolving it fails, it is said to have no <a href="#global-identifier">global
  identifier</a>.<p>The <code title="attr-itemid"><a href="#attr-itemid">itemid</a></code> attribute must not be
  specified on elements that do not have both an <code title="attr-itemscope"><a href="#attr-itemscope">itemscope</a></code> attribute and an <code title="attr-itemtype"><a href="#attr-itemtype">itemtype</a></code> attribute specified, and must
  not be specified on elements with an <code title="attr-itemscope"><a href="#attr-itemscope">itemscope</a></code> attribute whose <code title="attr-itemtype"><a href="#attr-itemtype">itemtype</a></code> attribute specifies a
  vocabulary that does not <a href="#support-global-identifiers-for-items">support global identifiers for
  items</a>, as defined by that vocabulary's specification.<hr><p>Elements with an <code title="attr-itemscope"><a href="#attr-itemscope">itemscope</a></code>
  attribute may have an <dfn id="attr-itemref" title="attr-itemref"><code>itemref</code></dfn> attribute specified,
  to give a list of additional elements to crawl to find the
  name-value pairs of the <a href="#concept-item" title="concept-item">item</a>.<p>The <code title="attr-itemref"><a href="#attr-itemref">itemref</a></code> attribute, if
  specified, must have a value that is an <a href="#unordered-set-of-unique-space-separated-tokens">unordered set of
  unique space-separated tokens</a> that are
  <span>case-sensitive</span>, consisting of <a href="#concept-id" title="concept-ID">IDs</a> of elements in the same <a href="#home-subtree">home
  subtree</a>.<p>The <code title="attr-itemref"><a href="#attr-itemref">itemref</a></code> attribute must not
  be specified on elements that do not have an <code title="attr-itemscope"><a href="#attr-itemscope">itemscope</a></code> attribute specified.<h3 id="names:-the-itemprop-attribute"><span class="secno">3.3 </span>Names: the <dfn title="attr-itemprop"><code>itemprop</code></dfn> attribute</h3><p>Every <a href="#html-elements" title="HTML elements">HTML element</a> may have an
  <code title="attr-itemprop"><a href="#names:-the-itemprop-attribute">itemprop</a></code> attribute specified, if
  doing so <a href="#the-properties-of-an-item" title="the properties of an item">adds a
  property</a> to one or more <a href="#concept-item" title="concept-item">items</a> (as defined below).<p>The <code title="attr-itemprop"><a href="#names:-the-itemprop-attribute">itemprop</a></code> attribute, if
  specified, must have a value that is an <a href="#unordered-set-of-unique-space-separated-tokens">unordered set of
  unique space-separated tokens</a> that are
  <span>case-sensitive</span>, representing the names of the
  name-value pairs that it adds. The attribute's value must have at
  least one token.<p>Each token must be either:<ul><li>A <a href="#valid-url">valid URL</a> that is an <a href="#absolute-url">absolute URL</a>
   for which the string "<code title="">http://www.w3.org/1999/xhtml/microdata#</code>" is not a
   <a href="#prefix-match">prefix match</a>, or</li>

   <li>If the item is a <a href="#typed-item">typed item</a>: a <dfn id="defined-property-name">defined
   property name</dfn> allowed in this situation according to the
   specification that defines the <a href="#relevant-type">relevant type</a> for the
   item, or</li>

   <li>If the item is not a <a href="#typed-item">typed item</a>: a string that
   contains no U+002E FULL STOP characters (.) and no U+003A COLON
   characters (:).</li>

  </ul><p>Specifications that introduce <a href="#defined-property-name" title="defined property
  name">defined property names</a> that are not <a href="#absolute-url" title="absolute URL">absolute URLs</a> must ensure all such
  property names contain no U+002E FULL STOP characters (.), no U+003A
  COLON characters (:), and no <span title="space character">space
  characters</span>.<p>When an element with an <code title="concept-itemprop">itemprop</code> attribute <a href="#the-properties-of-an-item" title="the
  properties of an item">adds a property</a> to multiple <a href="#concept-item" title="concept-item">items</a>, the requirement above regarding
  the tokens applies for each <a href="#concept-item" title="concept-item">item</a>
  individually.</p><p>The <dfn id="property-names">property names</dfn> of an element are the tokens that
  the element's <code title="attr-itemprop"><a href="#names:-the-itemprop-attribute">itemprop</a></code> attribute
  is found to contain when its value is <a href="#split-a-string-on-spaces" title="split a string on
  spaces">split on spaces</a>, with the order preserved but with
  duplicates removed (leaving only the first occurrence of each
  name).<p>Within an <a href="#concept-item" title="concept-item">item</a>, the properties
  are unordered with respect to each other, except for properties with
  the same name, which are ordered in the order they are given by the
  algorithm that defines <a href="#the-properties-of-an-item">the properties of an item</a>.<div class="example">

   <p>In the following example, the "a" property has the values "1"
   and "2", <em>in that order</em>, but whether the "a" property comes
   before the "b" property or not is not important:</p>

   <pre>&lt;div itemscope&gt;
 &lt;p itemprop="a"&gt;1&lt;/p&gt;
 &lt;p itemprop="a"&gt;2&lt;/p&gt;
 &lt;p itemprop="b"&gt;test&lt;/p&gt;
&lt;/div&gt;</pre>

   <p>Thus, the following is equivalent:</p>

   <pre>&lt;div itemscope&gt;
 &lt;p itemprop="b"&gt;test&lt;/p&gt;
 &lt;p itemprop="a"&gt;1&lt;/p&gt;
 &lt;p itemprop="a"&gt;2&lt;/p&gt;
&lt;/div&gt;</pre>

   <p>As is the following:</p>

   <pre>&lt;div itemscope&gt;
 &lt;p itemprop="a"&gt;1&lt;/p&gt;
 &lt;p itemprop="b"&gt;test&lt;/p&gt;
 &lt;p itemprop="a"&gt;2&lt;/p&gt;
&lt;/div&gt;</pre>

   <p>And the following:</p>

   <pre>&lt;div itemscope itemref="x"&gt;
 &lt;p itemprop="b"&gt;test&lt;/p&gt;
 &lt;p itemprop="a"&gt;2&lt;/p&gt;
&lt;/div&gt;
&lt;div id="x"&gt;
 &lt;p itemprop="a"&gt;1&lt;/p&gt;
&lt;/div&gt;
</pre>

  </div><h3 id="values"><span class="secno">3.4 </span>Values</h3><p>The <dfn id="concept-property-value" title="concept-property-value">property value</dfn> of a
  name-value pair added by an element with an <code title="attr-itemprop"><a href="#names:-the-itemprop-attribute">itemprop</a></code> attribute depends on the
  element, as follows:<dl><dt>If the element also has an <code title="attr-itemscope"><a href="#attr-itemscope">itemscope</a></code> attribute</dt>

   <dd><p>The value is the <a href="#concept-item" title="concept-item">item</a>
   created by the element.</dd>


   <dt>If the element is a <code>meta</code> element</dt>

   <dd><p>The value is the value of the element's <code title="attr-content">content</code> attribute, if any, or the empty
   string if there is no such attribute.</dd>


   <dt>If the element is an <code>audio</code>, <code>embed</code>,
   <code>iframe</code>, <code>img</code>, <code>source</code>,
   <code>track</code>, or <code>video</code> element</dt>

   <dd><p>The value is the <a href="#absolute-url">absolute URL</a> that results from
   <a href="#resolve-a-url" title="resolve a url">resolving</a> the value of the
   element's <code title="">src</code> attribute relative to the
   element at the time the attribute is set, or the empty string if
   there is no such attribute or if <a href="#resolve-a-url" title="resolve a
   url">resolving</a> it results in an error.</dd>


   <dt>If the element is an <code>a</code>, <code>area</code>, or
   <code>link</code> element</dt>

   <dd><p>The value is the <a href="#absolute-url">absolute URL</a> that results from
   <a href="#resolve-a-url" title="resolve a url">resolving</a> the value of the
   element's <code title="">href</code> attribute relative to the
   element at the time the attribute is set, or the empty string if
   there is no such attribute or if <a href="#resolve-a-url" title="resolve a
   url">resolving</a> it results in an error.</dd>


   <dt>If the element is an <code>object</code> element</dt>

   <dd><p>The value is the <a href="#absolute-url">absolute URL</a> that results from
   <a href="#resolve-a-url" title="resolve a url">resolving</a> the value of the
   element's <code title="">data</code> attribute relative to the
   element at the time the attribute is set, or the empty string if
   there is no such attribute or if <a href="#resolve-a-url" title="resolve a
   url">resolving</a> it results in an error.</dd>


   <dt>If the element is a <code>time</code> element with a <code title="attr-time-datetime">datetime</code> attribute</dt>

   <dd><p>The value is the value of the element's <code title="attr-time-datetime">datetime</code> attribute.</dd>


   <dt>Otherwise</dt>

   <dd><p>The value is the element's
   <code>textContent</code>.</dd>

  </dl><p>The <dfn id="url-property-elements">URL property elements</dfn> are the <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>, and
  <code>video</code> elements.<p>If a property's <a href="#concept-property-value" title="concept-property-value">value</a>
  is an <a href="#absolute-url">absolute URL</a>, the property must be specified
  using a <a href="#url-property-elements" title="URL property elements">URL property
  element</a>.<p>If a property's <a href="#concept-property-value" title="concept-property-value">value</a>
  represents a <a href="#concept-date" title="concept-date">date</a>, <a href="#concept-time" title="concept-time">time</a>, or <a href="#concept-datetime" title="concept-datetime">global date and time</a>, the property
  must be specified using the <code title="attr-time-datetime">datetime</code> attribute of a
  <code>time</code> element.<h3 id="associating-names-with-items"><span class="secno">3.5 </span>Associating names with items</h3><p>To find <dfn id="the-properties-of-an-item">the properties of an item</dfn> defined by the
  element <var title="">root</var>, the user agent must try to
  <a href="#crawl-the-properties">crawl the properties</a> of the element <var title="">root</var>, with an empty list as the value of <var title="">memory</var>: if this fails, then <a href="#the-properties-of-an-item" title="the
  properties of an item">the properties of the item</a> defined by
  the element <var title="">root</var> is an empty list; otherwise, it
  is the returned list.<p>To <dfn id="crawl-the-properties">crawl the properties</dfn> of an element <var title="">root</var> with a list <var title="">memory</var>, the user
  agent must run the following steps. These steps either fail or
  return a list with a count of errors. The count of errors is used as
  part of the authoring conformance criteria below.<ol><li><p>If <var title="">root</var> is in <var title="">memory</var>, then the algorithm fails; abort these
   steps.</li>

   <li><p><a href="#collect-all-the-elements-in-the-item">Collect all the elements in the item</a> <var title="">root</var>; let <var title="">results</var> be the
   resulting list of elements, and <var title="">errors</var> be the
   resulting count of errors.</li>

   <li><p>Remove any elements from <var title="">results</var> that do
   not have an <code title="attr-itemprop"><a href="#names:-the-itemprop-attribute">itemprop</a></code> attribute
   specified.</li>

   <li><p>Let <var title="">new memory</var> be a new list consisting
   of the old list <var title="">memory</var> with the addition of
   <var title="">root</var>.</li>

   <li><p>For each element in <var title="">results</var> that has an
   <code title="attr-itemscope"><a href="#attr-itemscope">itemscope</a></code> attribute specified,
   <a href="#crawl-the-properties">crawl the properties</a> of the element, with <var title="">new memory</var> as the memory. If this fails, then remove
   the element from <var title="">results</var> and increment <var title="">errors</var>. (If it succeeds, the return value is
   discarded.)</li>

   <li><p>Sort <var title="">results</var> in <a href="#tree-order">tree
   order</a>.</li>

   <li><p>Return <var title="">results</var> and <var title="">errors</var>.</li>

  </ol><p>To <dfn id="collect-all-the-elements-in-the-item">collect all the elements in the item</dfn> <var title="">root</var>, the user agent must run these steps. They
  return a list of elements and a count of errors.<ol><li><p>Let <var title="">results</var> and <var title="">pending</var> be empty lists of elements.</li>

   <li><p>Let <var title="">errors</var> be zero.</li>

   <li><p>Add all the children elements of <var title="">root</var> to
   <var title="">pending</var>.</li>

   <li><p>If <var title="">root</var> has an <code title="attr-itemref"><a href="#attr-itemref">itemref</a></code> attribute, <a href="#split-a-string-on-spaces" title="split a
   string on spaces">split the value of that <code title="attr-itemref">itemref</code> attribute on spaces</a>. For
   each resulting token <var title="">ID</var>, if there is an element
   in the <a href="#home-subtree">home subtree</a> of <var title="">root</var> with
   the <a href="#concept-id" title="concept-ID">ID</a> <var title="">ID</var>, then
   add the first such element to <var title="">pending</var>.</li>

   <li><p><i>Loop</i>: Remove an element from <var title="">pending</var> and let <var title="">current</var> be that
   element.</li>

   <li><p>If <var title="">current</var> is already in <var title="">results</var>, increment <var title="">errors</var>.</li>

   <li><p>If <var title="">current</var> is not already in <var title="">results</var> and <var title="">current</var> does not
   have an <code title="attr-itemscope"><a href="#attr-itemscope">itemscope</a></code> attribute,
   then: add all the child elements of <var title="">current</var> to
   <var title="">pending</var>.</li>

   <li><p>If <var title="">current</var> is not already in <var title="">results</var>, then: add <var title="">current</var> to
   <var title="">results</var>.</li>

   <li><p><i>End of loop</i>: If <var title="">pending</var> is not
   empty, return to the step labeled <i>loop</i>.</li>

   <li><p>Return <var title="">results</var> and <var title="">errors</var>.</li>

  </ol><p>An <a href="#concept-item" title="concept-item">item</a> is a <dfn id="top-level-microdata-items" title="top-level microdata items">top-level microdata item</dfn> if
  its element does not have an <code title="attr-itemprop"><a href="#names:-the-itemprop-attribute">itemprop</a></code> attribute.<p>An <a href="#concept-item" title="concept-item">item</a> is a <dfn id="used-microdata-items" title="used
  microdata items">used microdata item</dfn> if it is a <a href="#top-level-microdata-items" title="top-level microdata items">top-level microdata item</a>,
  or if it has an <code title="attr-itemprop"><a href="#names:-the-itemprop-attribute">itemprop</a></code>
  attribute and would be <a href="#the-properties-of-an-item" title="the properties of an item">found
  to be the property</a> of an <a href="#concept-item" title="concept-item">item</a> that is itself a <a href="#used-microdata-items" title="used
  microdata items">used microdata item</a>.<p>All <a href="#concept-item" title="concept-item">items</a> in a document must be
  <a href="#used-microdata-items">used microdata items</a>.<p>A document must not contain any elements that have an <code title="attr-itemprop"><a href="#names:-the-itemprop-attribute">itemprop</a></code> attribute that would not be
  found to be a property of any of the <a href="#concept-item" title="concept-item">items</a> in that document were their <a href="#the-properties-of-an-item" title="the properties of an item">properties</a> all to be
  determined.<p>A document must not contain any <a href="#concept-item" title="concept-item">items</a> for which <a href="#crawl-the-properties" title="crawl the
  properties">crawling the properties</a> of the element, with an
  empty list as the value of <var title="">memory</var>, either fails
  or returns an error count other than zero.<p class="note">The algorithms in this section are especially
  inefficient, in the interests of keeping them easy to
  understand. Implementors are strongly encouraged to refactor and
  optimize them in their user agents.<div class="example">

   <p>In this example, a single license statement is applied to two
   works, using <code title="attr-itemref"><a href="#attr-itemref">itemref</a></code> from the
   items representing the works:</p>

   <pre>&lt;!DOCTYPE HTML&gt;
&lt;html&gt;
 &lt;head&gt;
  &lt;title&gt;Photo gallery&lt;/title&gt;
 &lt;/head&gt;
 &lt;body&gt;
  &lt;h1&gt;My photos&lt;/h1&gt;
  &lt;figure itemscope itemtype="http://n.whatwg.org/work" itemref="licenses"&gt;
   &lt;img itemprop="work" src="images/house.jpeg" alt="A white house, boarded up, sits in a forest."&gt;
   &lt;figcaption itemprop="title"&gt;The house I found.&lt;/figcaption&gt;
  &lt;/figure&gt;
  &lt;figure itemscope itemtype="http://n.whatwg.org/work" itemref="licenses"&gt;
   &lt;img itemprop="work" src="images/mailbox.jpeg" alt="Outside the house is a mailbox. It has a leaflet inside."&gt;
   &lt;figcaption itemprop="title"&gt;The mailbox.&lt;/figcaption&gt;
  &lt;/figure&gt;
  &lt;footer&gt;
   &lt;p id="licenses"&gt;All images licensed under the &lt;a itemprop="license"
   href="http://www.opensource.org/licenses/mit-license.php"&gt;MIT
   license&lt;/a&gt;.&lt;/p&gt;
  &lt;/footer&gt;
 &lt;/body&gt;
&lt;/html&gt;</pre>

   <p>The above results in two items with the type "<code title="">http://n.whatwg.org/work</code>", one with:</p>

   <dl class="brief"><dt>work
    <dd><code title="">images/house.jpeg</code>
    <dt>title
    <dd>The house I found.
    <dt>license
    <dd><code title="">http://www.opensource.org/licenses/mit-license.php</code>
   </dl><p>...and one with:</p>

   <dl class="brief"><dt>work
    <dd><code title="">images/mailbox.jpeg</code>
    <dt>title
    <dd>The mailbox.
    <dt>license
    <dd><code title="">http://www.opensource.org/licenses/mit-license.php</code>
   </dl></div><h2 id="microdata-dom-api"><span class="secno">4 </span>Microdata DOM API</h2><pre class="idl">[Supplemental] interface <a href="#htmldocument">HTMLDocument</a> {
  NodeList <a href="#dom-document-getitems" title="dom-document-getItems">getItems</a>(in optional DOMString typeNames); // <span>microdata</span>
};

[Supplemental] interface <a href="#htmlelement">HTMLElement</a> {
  // <span>microdata</span>
           attribute boolean <a href="#dom-itemscope" title="dom-itemScope">itemScope</a>;
           attribute DOMString <a href="#dom-itemtype" title="dom-itemType">itemType</a>;
           attribute DOMString <a href="#dom-itemid" title="dom-itemId">itemId</a>;
  [PutForwards=<span title="dom-DOMSettableTokenList-value">value</span>] readonly attribute <span>DOMSettableTokenList</span> <a href="#dom-itemref" title="dom-itemRef">itemRef</a>;
  [PutForwards=<span title="dom-DOMSettableTokenList-value">value</span>] readonly attribute <span>DOMSettableTokenList</span> <a href="#dom-itemprop" title="dom-itemProp">itemProp</a>;
  readonly attribute <a href="#htmlpropertiescollection">HTMLPropertiesCollection</a> <a href="#dom-properties" title="dom-properties">properties</a>;
           attribute any <a href="#dom-itemvalue" title="dom-itemValue">itemValue</a>;
};</pre><dl class="domintro"><dt><var title="">document</var> . <code title="dom-document-getItems"><a href="#dom-document-getitems">getItems</a></code>( [ <var title="">types</var> ] )</dt>

   <dd>

    <p>Returns a <code>NodeList</code> of the elements in the <code>Document</code> that create <a href="#concept-item" title="concept-item">items</a>, that are not part of other <a href="#concept-item" title="concept-item">items</a>, and that are of one of the types given in the argument, if any are listed.</p>

    <p>The <var title="">types</var> argument is interpreted as a space-separated list of types.</p>

   </dd>

   <dt><var title="">element</var> . <code title="dom-properties"><a href="#dom-properties">properties</a></code></dt>

   <dd>

    <p>If the element has an <code title="attr-itemscope"><a href="#attr-itemscope">itemscope</a></code> attribute, returns an
    <code><a href="#htmlpropertiescollection">HTMLPropertiesCollection</a></code> object with all the element's
    properties. Otherwise, an empty
    <code><a href="#htmlpropertiescollection">HTMLPropertiesCollection</a></code> object.</p>

   </dd>

   <dt><var title="">element</var> . <code title="dom-itemValue"><a href="#dom-itemvalue">itemValue</a></code> [ = <var title="">value</var> ]</dt>

   <dd>

    <p>Returns the element's <a href="#concept-property-value" title="concept-property-value">value</a>.</p>

    <p>Can be set, to change the element's <a href="#concept-property-value" title="concept-property-value">value</a>. Setting the <a href="#concept-property-value" title="concept-property-value">value</a> when the element has
    no <code title="attr-itemprop"><a href="#names:-the-itemprop-attribute">itemprop</a></code> attribute or when
    the element's value is an <a href="#concept-item" title="concept-item">item</a>
    throws an <code>INVALID_ACCESS_ERR</code> exception.</p>

   </dd>

  </dl><div class="impl">

  <p>The <dfn id="dom-document-getitems" title="dom-document-getItems"><code>document.getItems(<var title="">typeNames</var>)</code></dfn> method takes an optional
  string that contains an <a href="#unordered-set-of-unique-space-separated-tokens">unordered set of unique
  space-separated tokens</a> that are <span>case-sensitive</span>,
  representing types. When called, the method must return a
  <span>live</span> <code>NodeList</code> object containing all the
  elements in the document, in <a href="#tree-order">tree order</a>, that are each
  <a href="#top-level-microdata-items">top-level microdata items</a> with a <a href="#item-type" title="item
  type">type</a> equal to one of the types specified in that
  argument, having obtained the types by <a href="#split-a-string-on-spaces" title="split a string
  on spaces">splitting the string on spaces</a>. If there are no
  tokens specified in the argument, or if the argument is missing,
  then the method must return a <code>NodeList</code> containing all
  the <a href="#top-level-microdata-items">top-level microdata items</a> in the document. When the
  method is invoked on a <code>Document</code> object again with the
  same argument, the user agent may return the same object as the
  object returned by the earlier call. In other cases, a new
  <code>NodeList</code> object must be returned.</p>

  <p>The <dfn id="dom-itemscope" title="dom-itemScope"><code>itemScope</code></dfn> IDL
  attribute on <a href="#html-elements">HTML elements</a> must <a href="#reflect">reflect</a>
  the <code title="attr-itemscope"><a href="#attr-itemscope">itemscope</a></code> content attribute.
  The <dfn id="dom-itemtype" title="dom-itemType"><code>itemType</code></dfn> IDL
  attribute on <a href="#html-elements">HTML elements</a> must <a href="#reflect">reflect</a>
  the <code title="attr-itemtype"><a href="#attr-itemtype">itemtype</a></code> content attribute,
  as if it was a regular string attribute, not a <a href="#url">URL</a>
  string attribute.  The <dfn id="dom-itemid" title="dom-itemId"><code>itemId</code></dfn> IDL attribute on
  <a href="#html-elements">HTML elements</a> must <a href="#reflect">reflect</a> the <code title="attr-itemid"><a href="#attr-itemid">itemid</a></code> content attribute. The <dfn id="dom-itemprop" title="dom-itemProp"><code>itemProp</code></dfn> IDL attribute on
  <a href="#html-elements">HTML elements</a> must <a href="#reflect">reflect</a> the <code title="attr-itemprop"><a href="#names:-the-itemprop-attribute">itemprop</a></code> content attribute. The <dfn id="dom-itemref" title="dom-itemRef"><code>itemRef</code></dfn> IDL attribute on
  <a href="#html-elements">HTML elements</a> must <a href="#reflect">reflect</a> the <code title="attr-itemref"><a href="#attr-itemref">itemref</a></code> content attribute.</p>

  <p>The <dfn id="dom-properties" title="dom-properties"><code>properties</code></dfn> IDL
  attribute on <a href="#html-elements">HTML elements</a> must return an
  <code><a href="#htmlpropertiescollection">HTMLPropertiesCollection</a></code> rooted at the
  <code>Document</code> node, whose filter matches only elements that
  have <a href="#property-names">property names</a> and are <a href="#the-properties-of-an-item" title="the properties
  of an item">the properties of the item</a> created by the element
  on which the attribute was invoked, while that element is an <a href="#concept-item" title="concept-item">item</a>, and matches nothing the rest of
  the time.</p>

  <p>The <dfn id="dom-itemvalue" title="dom-itemValue"><code>itemValue</code></dfn> IDL
  attribute's behavior depends on the element, as follows:</p>

  <dl><dt>If the element has no <code title="attr-itemprop"><a href="#names:-the-itemprop-attribute">itemprop</a></code> attribute</dt>

   <dd><p>The attribute must return null on getting and must throw an
   <code>INVALID_ACCESS_ERR</code> exception on setting.</p>


   <dt>If the element has an <code title="attr-itemscope"><a href="#attr-itemscope">itemscope</a></code> attribute</dt>

   <dd><p>The attribute must return the element itself on getting and
   must throw an <code>INVALID_ACCESS_ERR</code> exception on
   setting.</p>


   <dt>If the element is a <code>meta</code> element</dt>

   <dd><p>The attribute must act as it would if it was <a href="#reflect" title="reflect">reflecting</a> the element's <code title="attr-meta-content">content</code> content
   attribute.</dd>


   <dt>If the element is an <code>audio</code>, <code>embed</code>,
   <code>iframe</code>, <code>img</code>, <code>source</code>,
   <code>track</code>, or <code>video</code> element</dt>

   <dd><p>The attribute must act as it would if it was <a href="#reflect" title="reflect">reflecting</a> the element's <code title="">src</code> content attribute.</dd>


   <dt>If the element is an <code>a</code>, <code>area</code>, or
   <code>link</code> element</dt>

   <dd><p>The attribute must act as it would if it was <a href="#reflect" title="reflect">reflecting</a> the element's <code title="">href</code> content attribute.</dd>


   <dt>If the element is an <code>object</code> element</dt>

   <dd><p>The attribute must act as it would if it was <a href="#reflect" title="reflect">reflecting</a> the element's <code title="">data</code> content attribute.</dd>


   <dt>If the element is a <code>time</code> element with a <code title="attr-time-datetime">datetime</code> attribute</dt>

   <dd><p>The attribute must act as it would if it was <a href="#reflect" title="reflect">reflecting</a> the element's <code title="attr-time-datetime">datetime</code> content
   attribute.</dd>


   <dt>Otherwise</dt>

   <dd><p>The attribute must act the same as the element's
   <code>textContent</code> attribute.</dd>

  </dl><p>When the <code title="dom-itemValue"><a href="#dom-itemvalue">itemValue</a></code> IDL
  attribute is <a href="#reflect" title="reflect">reflecting</a> a content
  attribute or acting like the element's <code>textContent</code>
  attribute, the user agent must, on setting, convert the new value to
  the IDL <code title="">DOMString</code> value before using it
  according to the mappings described above.</p>

  </div><div class="exmaple">

   <p>In this example, a script checks to see if a particular element
   <var title="">element</var> is declaring a particular property, and
   if it is, it increments a counter:</p>

   <pre>if (element.itemProp.contains('color'))
  count += 1;</pre>

  </div><div class="exmaple">

   <p>This script iterates over each of the values of an element's
   <code title="attr-itemref"><a href="#attr-itemref">itemref</a></code> attribute, calling a
   function for each referenced element:</p>

   <pre>for (var index = 0; index &lt; element.itemRef.length; index += 1)
  process(document.getElementById(element.itemRef[index]));</pre>

  </div><div class="impl">

  <h3 id="drag-and-drop"><span class="secno">4.1 </span>Drag-and-drop</h3>

  <p>The <a href="#drag-and-drop-initialization-steps">drag-and-drop initialization steps</a> are:

  <ol><li>
    <p>The user agent must take the <a href="#list-of-dragged-nodes">list of dragged nodes</a>
    and <a href="#extracting-json" title="extracting JSON">extract the microdata from those
    nodes into a JSON form</a>, and then must add the resulting
    string to the <code title="dom-DragEvent-dataTransfer">dataTransfer</code> member,
    associated with the <code title="">application/microdata+json</code> format.</p>
   </li>
  </ol></div><div class="impl">

  <h2 id="converting-html-to-other-formats"><span class="secno">5 </span>Converting HTML to other formats</h2>

  <h3 id="json"><span class="secno">5.1 </span>JSON</h3>

  <p>Given a list of nodes <var title="">nodes</var> in a
  <code>Document</code>, a user agent must run the following algorithm
  to <dfn id="extracting-json" title="extracting JSON">extract the microdata from those
  nodes into a JSON form</dfn>:</p>

  <ol><li><p>Let <var title="">result</var> be an empty object.</li>

   <li><p>Let <var title="">items</var> be an empty array.</li>

   <li><p>For each <var title="">node</var> in <var title="">nodes</var>, check if the element is a <a href="#top-level-microdata-items" title="top-level microdata items">top-level microdata item</a>,
   and if it is then <a href="#get-the-object">get the object</a> for that element and
   add it to <var title="">items</var>.</li>

   <li><p>Add an entry to <var title="">result</var> called "<code title="">items</code>" whose value is the array <var title="">items</var>.</li>

   <li><p>Return the result of serializing <var title="">result</var>
   to JSON.</li>

  </ol><p>When the user agent is to <dfn id="get-the-object">get the object</dfn> for an item
  <var title="">item</var>, it must run the following substeps:</p>

  <ol><li><p>Let <var title="">result</var> be an empty object.</li>

   <li><p>If the <var title="">item</var> has an <a href="#item-type">item
   type</a>, add an entry to <var title="">result</var> called
   "<code title="">type</code>" whose value is the <a href="#item-type">item
   type</a> of <var title="">item</var>.</li>

   <li><p>If the <var title="">item</var> has an <a href="#global-identifier">global
   identifier</a>, add an entry to <var title="">result</var>
   called "<code title="">id</code>" whose value is the <a href="#global-identifier">global
   identifier</a> of <var title="">item</var>.</li>

   <li><p>Let <var title="">properties</var> be an empty
   object.</li>

   <li>

    <p>For each element <var title="">element</var> that has one or
    more <a href="#property-names">property names</a> and is one of <a href="#the-properties-of-an-item" title="the
    properties of an item">the properties of the item</a> <var title="">item</var>, in the order those elements are given by the
    algorithm that returns <a href="#the-properties-of-an-item">the properties of an item</a>, run
    the following substeps:</p>

    <ol><li><p>Let <var title="">value</var> be the <a href="#concept-property-value" title="concept-property-value">property value</a> of <var title="">element</var>.</li>

     <li><p>If <var title="">value</var> is an <a href="#concept-item" title="concept-item">item</a>, then <a href="#get-the-object">get the
     object</a> for <var title="">value</var>, and then replace
     <var title="">value</var> with the object returned from those
     steps.</li>

     <li>

      <p>For each name <var title="">name</var> in <var title="">element</var>'s <a href="#property-names">property names</a>, run the
      following substeps:</p>

      <ol><li><p>If there is no entry named <var title="">name</var> in
       <var title="">properties</var>, then add an entry named <var title="">name</var> to <var title="">properties</var> whose
       value is an empty array.</li>

       <li><p>Append <var title="">value</var> to the entry named <var title="">name</var> in <var title="">properties</var>.</li>

      </ol></li>

    </ol></li>

   <li><p>Add an entry to <var title="">result</var> called "<code title="">properties</code>" whose value is the object <var title="">properties</var>.</li>

   <li><p>Return <var title="">result</var>.</li>

  </ol><h3 id="rdf"><span class="secno">5.2 </span>RDF</h3>

  <p>To <dfn id="extracting-rdf" title="extracting rdf">convert a <code>Document</code> to
  RDF</dfn>, a user agent must run the following algorithm:</p>

  <ol><li>

    <p>If <a href="#the-title-element">the <code>title</code> element</a> is not null,
    then generate the following triple:</p>

    <dl class="triple"><dt>subject   <dd> <a href="#the-document-s-current-address">the document's current address</a>
     <dt>predicate <dd> <code title="">http://purl.org/dc/terms/title</code>
     <dt>object    <dd> the concatenation of the data of all the child <span title="text node">text nodes</span> of <a href="#the-title-element">the <code>title</code> element</a>, in <a href="#tree-order">tree order</a>, as a plain literal, with the language information set from the <a href="#language">language</a> of <a href="#the-title-element">the <code>title</code> element</a>, if it is not unknown.

    </dl></li>

   <li>

    <p>For each <code>a</code>, <code>area</code>, and
    <code>link</code> element in the <code>Document</code>, run these
    substeps:</p>

    <ol><li><p>If the element does not have a <code title="">rel</code>
     attribute, then skip this element.</li>

     <li><p>If the element does not have an <code title="">href</code>
     attribute, then skip this element.</li>

     <li><p>If <a href="#resolve-a-url" title="resolve a URL">resolving</a> the
     element's <code title="">href</code> attribute relative to the
     element is not successful, then skip this element.</li>

     <li><p>Otherwise, <a href="#split-a-string-on-spaces" title="split a string on spaces">split
     the value of the element's <code title="">rel</code> attribute on
     spaces</a>, obtaining <var title="">list of tokens</var>.</li>

     <li><p>Convert each token in <var title="">list of tokens</var>
     that does not contain a U+003A COLON characters (:) <span title="converted to ASCII lowercase">to ASCII
     lowercase</span>.</li>

     <li><p>Coalesce duplicate tokens in <var title="">list of
     tokens</var>.</li>

     <li><p>If <var title="">list of tokens</var> contains both the
     tokens <code title="rel-alternate">alternate</code> and <code title="rel-stylesheet">stylesheet</code>, then remove them both
     and replace them with the single (uppercase) token <code title="">ALTERNATE-STYLESHEET</code>.</li>

     <li>

      <p>For each token <var title="">token</var> in <var title="">list of tokens</var> that contains no U+003A COLON
      characters (:), generate the following triple:</p>

      <dl class="triple"><dt>subject   <dd> <a href="#the-document-s-current-address">the document's current address</a>
       <dt>predicate <dd> the <span>fragment-escaped</span> concatenation of the string "<code title="">http://www.w3.org/1999/xhtml/vocab#</code>" and <var title="">token</var>
       <dt>object    <dd> the <a href="#absolute-url">absolute URL</a> that results from <a href="#resolve-a-url" title="resolve a URL">resolving</a> the value of the element's <code title="">href</code> attribute relative to the element
      </dl><p>For each token <var title="">token</var> in <var title="">list of tokens</var> that is an <a href="#absolute-url">absolute
      URL</a>, generate the following triple:</p>

      <dl class="triple"><dt>subject   <dd> <a href="#the-document-s-current-address">the document's current address</a>
       <dt>predicate <dd> <var title="">token</var>
       <dt>object    <dd> the <a href="#absolute-url">absolute URL</a> that results from <a href="#resolve-a-url" title="resolve a URL">resolving</a> the value of the element's <code title="">href</code> attribute relative to the element
      </dl></li>

    </ol></li>

   <li>

    <p>For each <code>meta</code> element in the <code>Document</code>
    that has a <code title="attr-meta-name">name</code> attribute and
    a <code title="attr-meta-content">content</code> attribute, if the
    value of the <code title="attr-meta-name">name</code> attribute
    contains no U+003A COLON characters (:), generate the following
    triple:</p>

    <dl class="triple"><dt>subject   <dd> <a href="#the-document-s-current-address">the document's current address</a>
     <dt>predicate <dd> the <span>fragment-escaped</span> concatenation of the string "<code title="">http://www.w3.org/1999/xhtml/vocab#</code>" and the value of the element's <code title="attr-meta-name">name</code> attribute, <span>converted to ASCII lowercase</span>
     <dt>object    <dd> the value of the element's <code title="attr-meta-content">content</code> attribute, as a plain literal, with the language information set from the <a href="#language">language</a> of the element, if it is not unknown
    </dl><p>For each <code>meta</code> element in the <code>Document</code>
    that has a <code title="attr-meta-name">name</code> attribute and
    a <code title="attr-meta-content">content</code> attribute, if the
    value of the <code title="attr-meta-name">name</code> attribute is
    an <a href="#absolute-url">absolute URL</a>, generate the following triple:</p>

    <dl class="triple"><dt>subject   <dd> <a href="#the-document-s-current-address">the document's current address</a>
     <dt>predicate <dd> the value of the element's <code title="attr-meta-name">name</code> attribute
     <dt>object    <dd> the value of the element's <code title="attr-meta-content">content</code> attribute, as a plain literal, with the language information set from the <a href="#language">language</a> of the element, if it is not unknown
    </dl></li>

   <li>

    <p>For each <code>blockquote</code> and <code>q</code> element in
    the <code>Document</code> that has a <code title="">cite</code>
    attribute that <a href="#resolve-a-url" title="resolve a url">resolves</a>
    successfully relative to the element, generate the following
    triple:</p>

    <dl class="triple"><dt>subject   <dd> <a href="#the-document-s-current-address">the document's current address</a>
     <dt>predicate <dd> <code title="">http://purl.org/dc/terms/source</code>
     <dt>object    <dd> the <a href="#absolute-url">absolute URL</a> that results from <a href="#resolve-a-url" title="resolve a URL">resolving</a> the value of the element's <code title="">cite</code> attribute relative to the element
    </dl></li>

   <li>

    <p>Let <var title="">memory</var> be a mapping of items to
    subjects, initially empty.</p>

   </li>

   <li>

    <p>For each element that is also a <a href="#top-level-microdata-items" title="top-level
    microdata items">top-level microdata item</a>, run the
    following steps:</p>

    <ol><li>

      <p><a href="#generate-the-triples-for-an-item" title="generate the triples for an item">Generate the
      triples for the item</a>. Pass a reference to <var title="">memory</var> as the item/subject list. Let <var title="">result</var> be the subject returned.</p>

     </li>

     <li>

      <p>Generate the following triple:</p>

      <dl class="triple"><dt>subject   <dd> <a href="#the-document-s-current-address">the document's current address</a>
       <dt>predicate <dd> <code title="">http://www.w3.org/1999/xhtml/microdata#item</code>
       <dt>object    <dd> <var title="">result</var>
      </dl></li>

    </ol></li>

  </ol><p>When the user agent is to <dfn id="generate-the-triples-for-an-item">generate the triples for an
  item</dfn> <var title="">item</var>, given a reference to an
  item/subject list <var title="">memory</var>, and optionally given a
  fallback type <var title="">fallback type</var> and property name
  <var title="">fallback name</var>, it must run the following
  steps:</p>

  <ol><li><p>If there is an entry for <var title="">item</var> in <var title="">memory</var>, then let <var title="">subject</var> be the
   subject of that entry. Otherwise, if <var title="">item</var> has a
   <a href="#global-identifier">global identifier</a> and that <a href="#global-identifier">global
   identifier</a> is an <a href="#absolute-url">absolute URL</a>, let <var title="">subject</var> be that <a href="#global-identifier">global
   identifier</a>. Otherwise, let <var title="">subject</var> be a
   new blank node.</li>

   <li><p>Add a mapping from <var title="">item</var> to <var title="">subject</var> in <var title="">memory</var>, if there
   isn't one already.</li>

   <li><p>If <var title="">item</var> has an <a href="#item-type">item type</a>
   and that <a href="#item-type">item type</a> is an <a href="#absolute-url">absolute URL</a>,
   let <var title="">type</var> be that <a href="#item-type">item
   type</a>. Otherwise, let <var title="">type</var> be the empty
   string.</li>


   <li>

    <p>If <var title="">type</var> is not the empty string, run the
    following steps:</p>

    <ol><li><p>Generate the following triple:</p>

      <dl class="triple"><dt>subject   <dd> <var title="">subject</var>
       <dt>predicate <dd> <code title="">http://www.w3.org/1999/02/22-rdf-syntax-ns#type</code>
       <dt>object    <dd> <var title="">type</var>
      </dl></li>

     <li><p>If <var title="">type</var> does not contain a U+0023
     NUMBER SIGN character (#), then append a U+0023 NUMBER SIGN
     character (#) to <var title="">type</var>.</li>

     <li><p>If <var title="">type</var> does not have a U+003A COLON
     character (:) after its U+0023 NUMBER SIGN character (#), append
     a U+003A COLON character (:) to <var title="">type</var>.</li>

    </ol></li>

   <li>

    <p>If <var title="">type</var> is the empty string, but <var title="">fallback type</var> is not, run the following
    substeps:</p>

    <ol><li><p>Let <var title="">type</var> have the value of <var title="">fallback type</var>.</li>

     <li><p>If <var title="">type</var> does not contain a U+0023
     NUMBER SIGN character (#), then append a U+0023 NUMBER SIGN
     character (#) to <var title="">type</var>.</li>


     <li><p>If <var title="">type</var> does not have a U+003A COLON
     character (:) after its U+0023 NUMBER SIGN character (#), append
     a U+003A COLON character (:) to <var title="">type</var>.</li>

     <li><p>If the last character of <var title="">type</var> is not a
     U+003A COLON character (:), append a U+0025 PERCENT SIGN
     character (%), a U+0032 DIGIT TWO character (2), and a U+0030
     DIGIT ZERO character (0) to <var title="">type</var>.</li>

     <li><p>Append the <span>fragment-escaped</span> value of <var title="">fallback name</var> to <var title="">type</var>.</li>

    </ol></li>

   <li>

    <p>For each element <var title="">element</var> that has one or
    more <a href="#property-names">property names</a> and is one of <a href="#the-properties-of-an-item" title="the
    properties of an item">the properties of the item</a> <var title="">item</var>, in the order those elements are given by the
    algorithm that returns <a href="#the-properties-of-an-item">the properties of an item</a>, run
    the following substep:</p>

    <ol><li>

      <p>For each name <var title="">name</var> in <var title="">element</var>'s <a href="#property-names">property names</a>, run the
      following substeps:</p>

      <ol><li><p>If <var title="">type</var> is the empty string and <var title="">name</var> is not an <a href="#absolute-url">absolute URL</a>, then
       abort these substeps.</li>

       <li><p>Let <var title="">value</var> be the <a href="#concept-property-value" title="concept-property-value">property value</a> of <var title="">element</var>.</li>

       <li><p>If <var title="">value</var> is an <a href="#concept-item" title="concept-item">item</a>, then <a href="#generate-the-triples-for-an-item" title="generate
       the triples for an item">generate the triples</a> for <var title="">value</var>. Pass a reference to <var title="">memory</var> as the item/subject list, and pass <var title="">type</var> as the fallback type and <var title="">name</var> as the fallback property name. Replace <var title="">value</var> by the subject returned from those
       steps.</li>


       <li><p>Otherwise, if <var title="">element</var> is not one of
       the <a href="#url-property-elements">URL property elements</a>, let <var title="">value</var> be a plain literal, with the language
       information set from the <a href="#language">language</a> of the element, if
       it is not unknown.</li>

       <li>

        <dl><dt>If <var title="">name</var> is an <a href="#absolute-url">absolute
         URL</a></dt>

         <dd>

          <p>Let <var title="">predicate</var> be <var title="">name</var>.</p>

         </dd>

         <dt>If <var title="">name</var> contains no U+003A COLON
         characters (:)</dt>

         <dd>

          <ol><li><p>Let <var title="">s</var> be <var title="">type</var>.</li>

           <li><p>If the last character of <var title="">s</var> is
           not a U+003A COLON character (:), append a U+0025 PERCENT
           SIGN character (%), a U+0032 DIGIT TWO character (2), and a
           U+0030 DIGIT ZERO character (0) to <var title="">s</var>.</li>

           <li><p>Append the <span>fragment-escaped</span> value of
           <var title="">name</var> to <var title="">s</var>.</li>

           <li>

            <p>Let <var title="">predicate</var> be the concatenation
            of the string "<code title="">http://www.w3.org/1999/xhtml/microdata#</code>"
            and the <span>fragment-escaped</span> value of <var title="">s</var>.</p>
            <p class="example">For example if the string <var title="">s</var> is "<code title="">http://example.com/a#:q%20r</code>", the
            resulting <var title="">predicate</var> would be "<code title="">http://www.w3.org/1999/xhtml/microdata#http://example.com/a%23:q%20r</code>".</p>

           </li>

          </ol></dd>

        </dl></li>

       <li>

        <p>Generate the following triple:</p>

        <dl class="triple"><dt>subject   <dd> <var title="">subject</var>
         <dt>predicate <dd> <var title="">predicate</var>
         <dt>object    <dd> <var title="">value</var>
        </dl></li>

      </ol></li>

    </ol></li>

   <li><p>Return <var title="">subject</var>.</li>

  </ol><h4 id="examples"><span class="secno">5.2.1 </span>Examples</h4>

  <p><i>This section is non-normative.</i></p>

  <div class="example">

   <p>Here is an example of some HTML using Microdata to express RDF
   statements:</p>

   <pre>&lt;dl itemscope
    itemtype="http://purl.org/vocab/frbr/core#Work"
    itemid="http://books.example.com/works/45U8QJGZSQKDH8N"&gt;
 &lt;dt&gt;Title&lt;/dt&gt;
 &lt;dd&gt;&lt;cite itemprop="http://purl.org/dc/terms/title"&gt;Just a Geek&lt;/cite&gt;&lt;/dd&gt;
 &lt;dt&gt;By&lt;/dt&gt;
 &lt;dd&gt;&lt;span itemprop="http://purl.org/dc/elements/1.1/creator"&gt;Wil Wheaton&lt;/span&gt;&lt;/dd&gt;
 &lt;dt&gt;Format&lt;/dt&gt;
 &lt;dd itemprop="http://purl.org/vocab/frbr/core#realization"
     itemscope
     itemtype="http://purl.org/vocab/frbr/core#Expression"
     itemid="http://books.example.com/products/9780596007683.BOOK"&gt;
  &lt;link itemprop="http://purl.org/dc/terms/type" href="http://books.example.com/product-types/BOOK"&gt;
  Print
 &lt;/dd&gt;
 &lt;dd itemprop="http://purl.org/vocab/frbr/core#realization"
     itemscope
     itemtype="http://purl.org/vocab/frbr/core#Expression"
     itemid="http://books.example.com/products/9780596802189.EBOOK"&gt;
  &lt;link itemprop="http://purl.org/dc/terms/type" href="http://books.example.com/product-types/EBOOK"&gt;
  Ebook
 &lt;/dd&gt;
&lt;/dl&gt;</pre>

   <p>This is equivalent to the following Turtle:</p>

  <pre class="turtle">@prefix dct: &lt;http://purl.org/dc/terms/&gt; .
 @prefix dce: &lt;http://purl.org/dc/elements/1.1/&gt; .
 @prefix frbr: &lt;http://purl.org/vocab/frbr/core#&gt; .

&lt;http://books.example.com/works/45U8QJGZSQKDH8N&gt; a frbr:Work ;
     dce:creator "Wil Wheaton"@en ;
     dct:title "Just a Geek"@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 ;
     dct:type &lt;http://books.example.com/product-types/BOOK&gt; .

&lt;http://books.example.com/products/9780596802189.EBOOK&gt; a frbr:Expression ;
     dct:type &lt;http://books.example.com/product-types/EBOOK&gt; .</pre>

  </div>

  <div class="example">

   <p>The following snippet of HTML has microdata for two people with
   the same address:</p>

   <pre>&lt;p&gt;
 Both
 &lt;span itemscope itemtype="http://microformats.org/profile/hcard" itemref="home"&gt;&lt;span itemprop="fn"
 &gt;&lt;span itemprop="n" itemscope&gt;&lt;span itemprop="given-name"&gt;Princeton&lt;/span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/span&gt;
 and
 &lt;span itemscope itemtype="http://microformats.org/profile/hcard" itemref="home"&gt;&lt;span itemprop="fn"
 &gt;&lt;span itemprop="n" itemscope&gt;&lt;span itemprop="given-name"&gt;Trekkie&lt;/span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/span&gt;
 live at
 &lt;span id="home" itemprop="adr" itemscope&gt;&lt;span itemprop="street-address"&gt;Avenue Q&lt;/span&gt;.&lt;/span&gt;
&lt;/p&gt;</pre>

   <p>It generates these triples expressed in Turtle (including a
   triple that in this case is expressed twice, though that is not
   meaningful in RDF):</p>

   <pre class="turtle">@prefix rdf: &lt;http://www.w3.org/1999/02/22-rdf-syntax-ns#&gt; .
@prefix dct: &lt;http://purl.org/dc/terms/&gt; .
@prefix hcard: &lt;http://www.w3.org/1999/xhtml/microdata#http://microformats.org/profile/hcard%23:&gt; .

&lt;&gt; &lt;http://www.w3.org/1999/xhtml/microdata#item&gt; _:n0 ;
   &lt;http://www.w3.org/1999/xhtml/microdata#item&gt; _:n1 .
_:n0  rdf:type &lt;http://microformats.org/profile/hcard&gt; ;
      hcard:fn "Princeton" ;
      hcard:n _:n0a
      hcard:adr _:n2 .
_:n0a hcard:n%20given-name "Princeton" .
_:n1  rdf:type &lt;http://microformats.org/profile/hcard&gt; ;
      hcard:fn "Trekkie" ;
      hcard:n _:n1a
      hcard:adr _:n2 .
_:n1a hcard:n%20given-name "Trekkie" .
_:n2  hcard:adr%20street-address "Avenue Q" ;
      hcard:adr%20street-address "Avenue Q" .</pre>

  </div>


  </div><h2 id="iana"><span class="secno">6 </span>IANA considerations</h2><h3 id="application-microdata-json"><span class="secno">6.1 </span><dfn><code>application/microdata+json</code></dfn></h3><p>This registration is for community review and will be submitted
  to the IESG for review, approval, and registration with IANA.</p><dl><dt>Type name:</dt>
   <dd>application</dd>
   <dt>Subtype name:</dt>
   <dd>microdata+json</dd>
   <dt>Required parameters:</dt>
   <dd>Same as for <code>application/json</code> <a href="#refsJSON">[JSON]</a></dd>
   <dt>Optional parameters:</dt>
   <dd>Same as for <code>application/json</code> <a href="#refsJSON">[JSON]</a></dd>
   <dt>Encoding considerations:</dt>
   <dd>Always UTF-8.</dd>
   <dt>Security considerations:</dt>
   <dd>Same as for <code>application/json</code> <a href="#refsJSON">[JSON]</a></dd>
   <dt>Interoperability considerations:</dt>
   <dd>Same as for <code>application/json</code> <a href="#refsJSON">[JSON]</a></dd>
   <dt>Published specification:</dt>
   <dd>

    Labeling a resource with the
    <code><a href="#application-microdata-json">application/microdata+json</a></code> type asserts that the
    resource is a JSON text that consists of an object with a single
    entry called "<code title="">items</code>" consisting of an array
    of entries, each of which consists of an object with an entry
    called "<code title="">id</code>" whose value is a string, an
    entry called "<code title="">type</code>" whose value is another
    string, and an entry called "<code title="">properties</code>"
    whose value is an object whose entries each have a value
    consisting of an array of either objects or strings, the objects
    being of the same form as the objects in the aforementioned "<code title="">items</code>" entry. As such, the relevant specifications
    are the JSON specification and this specification. <a href="#refsJSON">[JSON]</a>

   </dd>
   <dt>Applications that use this media type:</dt>
   <dd>Same as for <code>application/json</code> <a href="#refsJSON">[JSON]</a></dd>
   <dt>Additional information:</dt>
   <dd>
    <dl><dt>Magic number(s):</dt>
     <dd>Same as for <code>application/json</code> <a href="#refsJSON">[JSON]</a></dd>
     <dt>File extension(s):</dt>
     <dd>Same as for <code>application/json</code> <a href="#refsJSON">[JSON]</a></dd>
     <dt>Macintosh file type code(s):</dt>
     <dd>Same as for <code>application/json</code> <a href="#refsJSON">[JSON]</a></dd>
    </dl></dd>
   <dt>Person &amp; email address to contact for further information:</dt>
   <dd>Ian Hickson &lt;ian@hixie.ch&gt;</dd>
   <dt>Intended usage:</dt>
   <dd>Common</dd>
   <dt>Restrictions on usage:</dt>
   <dd>No restrictions apply.</dd>
   <dt>Author:</dt>
   <dd>Ian Hickson &lt;ian@hixie.ch&gt;</dd>
   <dt>Change controller:</dt>
   <dd>W3C</dd>
  </dl><p>Fragment identifiers used with
  <code><a href="#application-microdata-json">application/microdata+json</a></code> resources have the same
  semantics as when used with <code>application/json</code> (namely,
  at the time of writing, no semantics at all). <a href="#refsJSON">[JSON]</a><h2 class="no-num" id="references">References</h2><p>All references are normative unless marked "Non-normative".</p><dl><dt id="refsHTML5">[HTML5]</dt>
   <dd>
   (Non-normative)
   <cite><a href="http://dev.w3.org/html5/spec/">HTML5</a></cite>,
   I. Hickson. W3C.</dd>

   <dt id="refsJSON">[JSON]</dt>
   <dd><cite><a href="http://tools.ietf.org/html/rfc4627">The
   application/json Media Type for JavaScript Object Notation
   (JSON)</a></cite>, D. Crockford. IETF.</dd>

   <dt id="refsRFC2119">[RFC2119]</dt>
   <dd><cite><a href="http://tools.ietf.org/html/rfc2119">Key words for use in
   RFCs to Indicate Requirement Levels</a></cite>, S. Bradner. IETF.</dd>

   <dt id="refsWEBIDL">[WEBIDL]</dt>
      <dd><cite><a href="http://dev.w3.org/2006/webapi/WebIDL/">Web
   IDL</a></cite>, C. McCormack. W3C.</dd>

  </dl><h2 class="no-num" id="acknowledgements">Acknowledgements</h2><p>Thanks to the participants of the microdata usability study for
  allowing us to use their mistakes as a guide for designing the
  microdata feature.<p>For a full list of acknowledgements, please see the HTML5
  specification. <a href="#refsHTML5">[HTML5]</a>