htmlbook.xsd

<?xml version="1.0"?>
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns="http://www.w3.org/1999/xhtml" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:svg="http://www.w3.org/2000/svg" targetNamespace="http://www.w3.org/1999/xhtml" elementFormDefault="qualified" attributeFormDefault="unqualified">

<xs:import namespace="http://www.w3.org/1998/Math/MathML" schemaLocation="mathml3/mathml3.xsd"/>
<xs:import namespace="http://www.w3.org/2000/svg" schemaLocation="svg/SVG.xsd"/>

<xs:element name="html">
  <xs:complexType>
    <xs:sequence>
      <xs:element ref="head"/>
      <xs:element ref="body"/>
    </xs:sequence>
    <xs:attributeGroup ref="globals"/>
  </xs:complexType>
</xs:element>
  
<xs:element name="head">
  <xs:complexType>
    <xs:sequence>
      <!-- Note that in order to produce a valid content model, title must be first -->
        <xs:element ref="title"/>
        <xs:choice minOccurs="0" maxOccurs="unbounded">
          <xs:element ref="base"/>
          <xs:element ref="command"/>
          <xs:element ref="link"/>
          <xs:element ref="meta"/>
          <xs:element ref="script"/>
          <xs:element ref="style"/>
      </xs:choice>
    </xs:sequence>
    <xs:attributeGroup ref="globals"/>
  </xs:complexType>
</xs:element>
  
<xs:element name="body">
  <xs:complexType>
    <xs:sequence>
      <xs:element ref="h1" minOccurs="0"/>
      <xs:element name="h2" minOccurs="0" type="subheading"/>
      <xs:element name="figure" minOccurs="0" type="coverfigure"/>
      <xs:choice maxOccurs="unbounded">
        <xs:element ref="nav"/>
        <xs:element name="section" type="bookmaindiv"/>
        <!-- Separate out parts, as they have specific child requirements -->
        <xs:element name="div" type="bookpart"/>
      </xs:choice>
    </xs:sequence>
    <xs:attribute name="data-type" use="required" fixed="book"/>
    <xs:attributeGroup ref="globals"/>
  </xs:complexType>
</xs:element>
  
<xs:element name="title">
  <xs:complexType mixed="true">
    <xs:complexContent>
      <xs:extension base="empty_elem_global_attrs"/>
    </xs:complexContent>
  </xs:complexType>
</xs:element>
  
<!-- HTML5 spec requires either href attr, target attr, or both, (not possible to represent this in Schema).
     In HTMLBook, we are formally requiring href -->
<xs:element name="base">
  <xs:complexType>
    <xs:complexContent>
      <xs:extension base="empty_elem_global_attrs">
        <xs:attribute name="href" type="xs:anyURI" use="required"/>
        <xs:attribute name="target" type="xs:string"/>
      </xs:extension>
    </xs:complexContent>
  </xs:complexType>
</xs:element>
    
<xs:element name="link">
  <xs:complexType>
    <xs:complexContent>
      <xs:extension base="empty_elem_global_attrs">
        <xs:attribute name="href" type="xs:anyURI" use="required"/>
        <xs:attribute name="hreflang" type="xs:language"/>
        <xs:attribute name="media" type="xs:string"/>
        <xs:attribute name="ref" type="xs:NMTOKENS"/>
        <xs:attribute name="sizes" type="xs:NMTOKENS"/>
        <xs:attribute name="type" type="xs:string"/>
      </xs:extension>
    </xs:complexContent>
  </xs:complexType>
</xs:element>

<!-- For HTMLBook, all book metadata should be encapsulated in name-value pairs using @name and @content attrs, respectively.
     These two attrs are required on each element.
-->
<xs:element name="meta">
  <xs:complexType>
    <xs:complexContent mixed="true">
      <xs:extension base="empty_elem_global_attrs">
        <xs:attribute name="name" type="xs:string" use="required"/>
        <xs:attribute name="content" type="xs:string" use="required"/>
        <xs:attribute name="charset" type="xs:string"/>
        <xs:attribute name="http-equiv">
          <xs:simpleType>
            <xs:restriction base="xs:token">
              <xs:enumeration value="content-language"/>
              <xs:enumeration value="content-type"/>
              <xs:enumeration value="default-style"/>
              <xs:enumeration value="refresh"/>
              <xs:enumeration value="set-cookie"/>
            </xs:restriction>
          </xs:simpleType>
        </xs:attribute>
      </xs:extension>
    </xs:complexContent>
  </xs:complexType>
</xs:element>

  <!-- Not supporting the "noscript" element in HTMLBook, as HTML5 spec states 
    "it has no effect in the XHTML syntax" (http://www.w3.org/TR/2011/WD-html5-20110525/scripting-1.html#the-noscript-element) -->
<!-- <xs:element name="noscript"> -->

<!-- In HTMLBook, not allowing JS content to be embedded directly in script tag, and are requiring a @src attr -->
<xs:element name="script">
  <xs:complexType>
    <xs:complexContent>
      <xs:extension base="empty_elem_global_attrs">
        <xs:attribute name="src" type="xs:anyURI" use="required"/>
        <xs:attribute name="async">
          <xs:simpleType>
            <xs:restriction base="xs:token">
              <xs:pattern value="([Aa][Ss][Yy][Nn][Cc])?"/>
            </xs:restriction>
          </xs:simpleType>
        </xs:attribute>
        <xs:attribute name="defer">
          <xs:simpleType>
            <xs:restriction base="xs:token">
              <xs:pattern value="([Dd][Ee][Ff][Ee][Rr])?"/>
            </xs:restriction>
          </xs:simpleType>
        </xs:attribute>
        <xs:attribute name="type" type="xs:string"/>
        <xs:attribute name="charset" type="xs:string"/>
      </xs:extension>
    </xs:complexContent>
  </xs:complexType>
</xs:element>
    
<xs:element name="style">
  <xs:complexType mixed="true">
      <xs:attribute name="media" type="xs:string"/>
      <xs:attribute name="type" type="xs:string"/>
      <xs:attribute name="scoped">
        <xs:simpleType>
          <xs:restriction base="xs:token">
            <xs:pattern value="([Ss][Cc][Oo][Pp][Ee][Dd])?"></xs:pattern>
          </xs:restriction>
        </xs:simpleType>
      </xs:attribute>
      <xs:attributeGroup ref="globals"/>
  </xs:complexType>
</xs:element>
  
<!-- Block elements -->
  
<!-- For now, limit "address" to support only inline element children -->
<xs:element name="address" type="inlines_mml_and_svg"/>

<xs:element name="aside" type="sidebar"/>

<!-- Note, per HTML5 spec, the actual requirements are a choice between:
    * a @src attribute on <audio> elem and no <source> children
    * no @src attribute on <audio> elem and 1 or more <source> children
    But this logic is impossible to capture in Schema, so not going to enforce -->
<xs:element name="audio">
  <xs:complexType mixed="true">
    <xs:sequence>
      <xs:element ref="source" minOccurs="0" maxOccurs="unbounded"/>
      <xs:element ref="track" minOccurs="0" maxOccurs="unbounded"/>
    </xs:sequence>
    <xs:attributeGroup ref="generalmediaattributes"/>
    <xs:attributeGroup ref="globals"/>
  </xs:complexType>
</xs:element>
  
<xs:element name="blockquote">
  <xs:complexType>
    <xs:complexContent>
      <xs:extension base="block_xor_inline_children">
        <xs:attribute name="cite" type="xs:anyURI"/>
      </xs:extension>
    </xs:complexContent>
  </xs:complexType>
</xs:element> 

<xs:element name="canvas">
  <xs:complexType>
    <xs:complexContent>
      <xs:extension base="block_xor_inline_children">
        <xs:attribute name="width" type="positive_int"/>
        <xs:attribute name="height" type="positive_int"/>
      </xs:extension>
    </xs:complexContent>
  </xs:complexType>
</xs:element>
  
<xs:element name="details">
  <xs:complexType mixed="true">
    <xs:sequence>
      <xs:element ref="summary" minOccurs="0" maxOccurs="1"/>
      <xs:choice>
        <xs:group ref="blockelements" minOccurs="0" maxOccurs="unbounded"/>
        <xs:group ref="inlineelements" minOccurs="0" maxOccurs="unbounded"/>
      </xs:choice>
    </xs:sequence>
    <xs:attribute name="open">
      <xs:simpleType>
        <xs:restriction base="xs:token">
          <xs:pattern value="([Oo][Pp][Ee][Nn])?"/>
        </xs:restriction>
      </xs:simpleType>
    </xs:attribute>
    <xs:attributeGroup ref="globals"/>
  </xs:complexType>
</xs:element>

<!-- Two choices for div content model:
     1. Block children only, with an optional h1-h6 to start
     2. Inline children only, no heading
-->
<xs:element name="div">
  <xs:complexType mixed="true">
    <xs:choice>
      <!-- Option 1: Optional heading(s) followed by block elements -->
      <xs:sequence>
        <xs:group ref="headings" minOccurs="0" maxOccurs="unbounded"/>
        <xs:group ref="blockelements" minOccurs="0" maxOccurs="unbounded"/>
      </xs:sequence>
      <!-- Option 2: inlines and text only -->
      <xs:group ref="inlineelements" minOccurs="0" maxOccurs="unbounded"/>
    </xs:choice>
    <xs:attributeGroup ref="globals"/>
  </xs:complexType>
</xs:element>
    
<xs:element name="dl">
  <xs:complexType>
    <xs:sequence maxOccurs="unbounded">
      <xs:element ref="dt" minOccurs="1" maxOccurs="unbounded"/>
      <xs:element ref="dd" minOccurs="1" maxOccurs="unbounded"/>
    </xs:sequence>
    <xs:attributeGroup ref="globals"/>
  </xs:complexType>
</xs:element>

<xs:element name="embed">
  <xs:complexType>
    <xs:complexContent>
      <xs:extension base="empty_elem_global_attrs">
        <xs:attribute name="src" type="xs:anyURI"/>
        <xs:attribute name="type" type="xs:string"/>
        <xs:attribute name="width" type="xs:string"/>
        <xs:attribute name="height" type="xs:string"/>
      </xs:extension>
    </xs:complexContent>
  </xs:complexType>
</xs:element>
  
<xs:element name="fieldset">
  <xs:complexType mixed="true">
    <xs:sequence>
      <xs:element ref="legend" minOccurs="0" maxOccurs="1"/>
      <xs:choice>
        <xs:group ref="blockelements" minOccurs="0" maxOccurs="unbounded"/>
        <xs:group ref="inlineelements" minOccurs="0" maxOccurs="unbounded"/>
      </xs:choice>
    </xs:sequence>
    <xs:attribute name="disabled" type="disabled_boolean"/>    
    <xs:attribute name="name" type="xs:string"/>
    <xs:attribute name="form" type="xs:IDREF"/>
    <xs:attributeGroup ref="globals"/>
  </xs:complexType>
</xs:element>

<!-- We're deviating from the HTML5 spec in that we're only allowing block elements inside figure,
     and we're requiring a caption (which can come at either beginning or end) -->
<xs:element name="figure">
  <xs:complexType>
    <xs:choice>
      <xs:sequence>
        <xs:element ref="figcaption"/>
        <xs:group ref="figure_elements" maxOccurs="unbounded"/>
      </xs:sequence>
      <xs:sequence>
        <xs:group ref="figure_elements" maxOccurs="unbounded"/>
        <xs:element ref="figcaption"/>
      </xs:sequence>
    </xs:choice>
    <xs:attributeGroup ref="globals"/>
  </xs:complexType>
</xs:element>

<!-- Custom type for cover figures; no caption -->
<xs:complexType name="coverfigure">
  <xs:group ref="figure_elements" maxOccurs="unbounded"/>
  <xs:attribute name="data-type" fixed="cover" use="required"/>
  <xs:attributeGroup ref="globals"/>
</xs:complexType>

<xs:element name="form">
  <xs:complexType>
    <xs:choice minOccurs="0" maxOccurs="unbounded">
      <!-- All block elements, except "form"; yes, I'm reproducing the list here, rather than split up the
           "blockelements" group -->
      <xs:element ref="address"/>
      <xs:element ref="aside"/>
      <xs:element ref="audio"/>
      <xs:element ref="blockquote"/>
      <xs:element ref="canvas"/>
      <xs:element ref="details"/>
      <xs:element ref="div"/>
      <xs:element ref="dl"/>
      <xs:element ref="embed"/>
      <xs:element ref="fieldset"/>
      <xs:element ref="figure"/>
      <xs:element ref="hr"/>
      <xs:element ref="iframe"/>
      <xs:element ref="map"/>
      <xs:element ref="mml:math"/>
      <xs:element ref="menu"/>
      <xs:element ref="object"/>
      <xs:element ref="ol"/>
      <xs:element ref="p"/>
      <xs:element ref="pre"/>
      <xs:element ref="svg:svg"/>
      <xs:element ref="table"/>
      <xs:element ref="ul"/>
      <xs:element ref="video"/>
    </xs:choice>
    <xs:attribute name="accept-charset" type="xs:NMTOKENS"/>
    <xs:attribute name="action">
      <xs:simpleType>
        <xs:restriction base="xs:anyURI">
          <xs:minLength value="1"/>
        </xs:restriction>
      </xs:simpleType>
    </xs:attribute>
    <xs:attribute name="autocomplete" type="on_off"/>
    <xs:attribute name="enctype" type="enctype_formenctype"/>    
    <xs:attribute name="method" type="method_formmethod"/>    
    <!-- HTML5 also requires a form's name attribute to be unique among all other forms' name attributes,
         but skipping that requirement here -->
    <xs:attribute name="name">
      <xs:simpleType>
        <xs:restriction base="xs:string">
          <xs:minLength value="1"/>
        </xs:restriction>
      </xs:simpleType>
    </xs:attribute>
    <xs:attribute name="novalidate">
      <xs:simpleType>
        <xs:restriction base="xs:token">
          <xs:pattern value="([Nn][Oo][Vv][Aa][Ll][Ii][Dd][Aa][Tt][Ee])?"/>
        </xs:restriction>
      </xs:simpleType>
    </xs:attribute>
    <xs:attribute name="target" type="xs:string"/>
    <xs:attributeGroup ref="globals"/>
  </xs:complexType>
</xs:element>
  
<xs:element name="hr" type="empty_elem_global_attrs"/>
  
<xs:element name="iframe">
  <xs:complexType mixed="true">
    <xs:group ref="inlineelements" minOccurs="0" maxOccurs="unbounded"/>
    <!-- Differing from HTML5 spec in that we're requiring a @src attribute here -->
    <xs:attribute name="src" use="required" type="xs:anyURI"/>
    <xs:attribute name="srcdoc" type="xs:string"/>
    <xs:attribute name="name" type="xs:string"/>
    <xs:attribute name="sandbox">
      <xs:simpleType>
        <xs:restriction base="xs:string">
          <!-- Ugly regex alert, because backreferences are not allowed in XML Schema -->
          <xs:pattern value="allow-(same-origin|top-navigation|forms|scripts)( allow-(same-origin|top-navigation|forms|scripts))*"/>
        </xs:restriction>
      </xs:simpleType>
    </xs:attribute>
    <xs:attribute name="seamless">
      <xs:simpleType>
        <xs:restriction base="xs:token">
          <xs:pattern value="([Ss][Ee][Aa][Mm][Ll][Ee][Ss][Ss])?"/>
        </xs:restriction>
      </xs:simpleType>
    </xs:attribute>
    <xs:attribute name="width" type="xs:string"/>
    <xs:attribute name="height" type="xs:string"/>
    <xs:attributeGroup ref="globals"/>
  </xs:complexType>
</xs:element>

<!-- Requiring block content model for "map" element for simplicity -->
<xs:element name="map">
  <xs:complexType>
    <xs:group ref="map_elements" minOccurs="0" maxOccurs="unbounded"/>
    <!-- Not enforcing two restrictions from HTML5 for name attribute: uniqueness against other name attributes on map, 
         and requirement that it match id value, if present -->
    <xs:attribute name="name" use="required">
      <xs:simpleType>
        <xs:restriction base="xs:token">
          <!-- nonempty and no spaces -->
          <xs:minLength value="1"/>
          <xs:pattern value="[^ ]*"></xs:pattern>
        </xs:restriction>
      </xs:simpleType>
    </xs:attribute>
    <xs:attributeGroup ref="globals"/>
  </xs:complexType>
</xs:element>

<!-- Not imposing any HTMLBook specific constraints on menu content; deferring to HTML5 spec -->
<xs:element name="menu">
  <xs:complexType>
    <xs:choice>
      <xs:element ref="li" maxOccurs="unbounded"/>
      <xs:choice>
        <xs:group ref="blockelements" minOccurs="0" maxOccurs="unbounded"/>
        <xs:group ref="inlineelements" minOccurs="0" maxOccurs="unbounded"/>
      </xs:choice>
    </xs:choice>
    <xs:attribute name="type">
      <xs:simpleType>
        <xs:restriction base="xs:token">
          <xs:enumeration value="context"/>
          <xs:enumeration value="toolbar"/>
        </xs:restriction>
      </xs:simpleType>
    </xs:attribute>
    <xs:attribute name="label" type="xs:string"/>
    <xs:attributeGroup ref="globals"/>
  </xs:complexType>
</xs:element>
  
<!--Follows the EPUB 3 spec for nav elements; see http://www.idpf.org/epub/30/spec/epub30-contentdocs.html#sec-xhtml-nav -->
<xs:element name="nav">
  <xs:complexType>
    <xs:sequence>
      <xs:group ref="headings" minOccurs="0"/>
      <xs:element name="ol" type="nav_doc_ol" minOccurs="0"/>
    </xs:sequence>
    <xs:attribute name="data-type" use="required" fixed="toc"/>
    <xs:attributeGroup ref="globals"/>
  </xs:complexType>
</xs:element>
  
<xs:element name="object">
  <xs:complexType mixed="true">
    <xs:sequence>
      <xs:element ref="param" minOccurs="0" maxOccurs="1"/>
      <xs:choice>
        <xs:group ref="blockelements" minOccurs="0" maxOccurs="unbounded"/>
        <xs:group ref="inlineelements" minOccurs="0" maxOccurs="unbounded"/>
      </xs:choice>
    </xs:sequence>
    <xs:attribute name="data">
      <xs:simpleType>
        <xs:restriction base="xs:anyURI">
          <xs:minLength value="1"/>
        </xs:restriction>
      </xs:simpleType>
    </xs:attribute>
    <xs:attribute name="type" type="xs:string"/>
    <xs:attribute name="name" type="xs:string"/>
    <xs:attribute name="usemap" type="hash_name"/>    
    <!-- form attribute must refer to ID of a <form> element, but we're just checking that it's an IDREF -->
    <xs:attribute name="form" type="xs:IDREF"/>
    <xs:attribute name="width" type="xs:string"/>
    <xs:attribute name="height" type="xs:string"/>
    <xs:attributeGroup ref="globals"/>
  </xs:complexType>
</xs:element>

<xs:element name="ol">
  <xs:complexType>
    <xs:sequence>
      <!-- "li"s in an "ol" can have a value attribute -->
      <xs:element name="li" minOccurs="0" maxOccurs="unbounded">
        <xs:complexType>
          <xs:complexContent>
            <xs:extension base="block_xor_inline_children">
              <xs:attribute name="value" type="positive_int"/>
            </xs:extension>
          </xs:complexContent>
        </xs:complexType>
      </xs:element>
    </xs:sequence>
    <xs:attributeGroup ref="ol_attrs"/>
    <xs:attributeGroup ref="globals"/>
  </xs:complexType>
</xs:element>
  
<xs:element name="p" type="inlines_mml_and_svg"/>
  
<xs:element name="pre">
  <xs:complexType>
    <xs:complexContent>
      <xs:extension base="inlines_mml_and_svg">
        <xs:attribute name="data-code-language" type="xs:token"/>
      </xs:extension>
    </xs:complexContent>
  </xs:complexType>
</xs:element>
  
<!-- Default global version of "section" element is for chapter-level book divisions
     (allows for modularization of HTML files at the chapter level),
     but see other complex types below for content models for lower-level sections --> 
<xs:element name="section" type="bookmaindiv"/>
  
<xs:element name="table">
  <xs:complexType>
    <xs:sequence>
      <xs:element ref="caption" minOccurs="0"/>
      <xs:element ref="colgroup" minOccurs="0" maxOccurs="unbounded"/>
      <xs:element ref="thead" minOccurs="0"/>
      <xs:choice>
        <xs:element ref="tbody" minOccurs="0" maxOccurs="unbounded"/>
        <xs:element ref="tr" maxOccurs="unbounded"/>
      </xs:choice>
      <!-- In order to simplify and ensure determinist content model, departing from the HTML5 spec
           and requiring tfoot to come at end of table, which is more intuitive anyway -->
      <xs:element ref="tfoot" minOccurs="0"/>
    </xs:sequence>
    <xs:attribute name="border">
      <xs:simpleType>
        <xs:restriction base="xs:string">
          <!-- Per HTML5 spec, we're accepting either the value 1 or an empty string here -->
          <xs:pattern value="1?"></xs:pattern>
        </xs:restriction>
      </xs:simpleType>
    </xs:attribute>
    <xs:attributeGroup ref="globals"/>
  </xs:complexType>
</xs:element>
  
<xs:element name="ul">
  <xs:complexType>
    <xs:sequence>
      <xs:element ref="li" minOccurs="0" maxOccurs="unbounded"/>
    </xs:sequence>
    <xs:attributeGroup ref="globals"/>
  </xs:complexType>
</xs:element>
  
<xs:element name="video">
  <xs:complexType mixed="true">
    <xs:sequence>
      <xs:element ref="source" minOccurs="0" maxOccurs="unbounded"/>
      <xs:element ref="track" minOccurs="0" maxOccurs="unbounded"/>
    </xs:sequence>
    <xs:attributeGroup ref="videomediaattributes"/>
    <xs:attributeGroup ref="globals"/>
  </xs:complexType>
</xs:element>
  
<!-- Inline elements -->

<!-- Open question: allow block content within an <a>? Right now, restricting only to inline elements -->   
<xs:element name="a">
  <xs:complexType>
    <xs:complexContent>
      <xs:extension base="inlines_mml_and_svg">
        <!-- ToDo: Any further attribute restrictions -->
        <xs:attribute name="href" type="xs:anyURI"/>
        <xs:attribute name="hreflang" type="xs:language"/>
        <xs:attribute name="rel" type="xs:NMTOKENS"/>
        <xs:attribute name="target" type="xs:string"/>
        <xs:attribute name="type" type="xs:string"/>
        <!-- The following attributes are for indexterms -->
        <xs:attribute name="data-primary" type="xs:string"/>
        <xs:attribute name="data-secondary" type="xs:string"/>
        <xs:attribute name="data-tertiary" type="xs:string"/>
        <xs:attribute name="data-see" type="xs:string"/>
        <xs:attribute name="data-seealso" type="xs:string"/>
        <xs:attribute name="data-sortas" type="xs:string"/>
      </xs:extension>
    </xs:complexContent>
  </xs:complexType>
</xs:element>
  
<xs:element name="abbr" type="inlines_mml_and_svg"/>

<xs:element name="b" type="inlines_mml_and_svg"/>
  
<xs:element name="bdi" type="inlines_mml_and_svg"/>
  
<xs:element name="bdo">
  <xs:complexType  mixed="true">
    <xs:sequence>
      <xs:group ref="inlines_plus_mml_and_svg" minOccurs="0" maxOccurs="unbounded"/>
    </xs:sequence>
    <!-- Adding the dir attribute here instead of specifying it in the "globals" attribute group
         to modify to include use="required" --> 
    <xs:attribute name="dir" use="required">
      <xs:simpleType>
        <xs:restriction base="xs:token">
          <xs:enumeration value="ltr"/>
          <xs:enumeration value="rtl"/>              
        </xs:restriction>
      </xs:simpleType>
    </xs:attribute>
    <xs:attributeGroup ref="globals_minus_dir"/>
  </xs:complexType>
</xs:element>
  
<xs:element name="br" type="empty_elem_global_attrs"/>

<xs:element name="button">
  <!-- button elements can have any inline children, excluding other interactive elements -->
  <xs:complexType mixed="true">
    <xs:choice minOccurs="0" maxOccurs="unbounded">
      <xs:element ref="a"/>
      <xs:element ref="abbr"/>
      <xs:element ref="b"/>
      <xs:element ref="bdi"/>
      <xs:element ref="bdo"/>
      <xs:element ref="br"/>
      <xs:element ref="cite"/>
      <xs:element ref="code"/>
      <xs:element ref="del"/>
      <xs:element ref="dfn"/>
      <xs:element ref="em"/>
      <xs:element ref="i"/>
      <xs:element ref="img"/>
      <xs:element ref="ins"/>
      <xs:element ref="kbd"/> 
      <xs:element ref="mark"/>  
      <xs:element ref="meter"/>
      <xs:element ref="output"/>
      <xs:element ref="progress"/>
      <xs:element ref="q"/>
      <xs:element ref="ruby"/>
      <xs:element ref="s"/>
      <xs:element ref="samp"/>
      <xs:element ref="small"/>
      <xs:element ref="span"/>
      <xs:element ref="strong"/>
      <xs:element ref="sub"/>
      <xs:element ref="sup"/>
      <xs:element ref="time"/>
      <xs:element ref="u"/>
      <xs:element ref="var"/>
      <xs:element ref="wbr"/>
    </xs:choice>
    <xs:attribute name="autofocus" type="autofocus_boolean"/>    
    <xs:attribute name="disabled" type="disabled_boolean"/>    
    <!-- form attribute must refer to ID of a <form> element, but we're just checking that it's an IDREF -->
    <xs:attribute name="form" type="xs:IDREF"/>
    <xs:attribute name="formaction">
      <xs:simpleType>
        <xs:restriction base="xs:anyURI">
          <xs:minLength value="1"/>
        </xs:restriction>
      </xs:simpleType>
    </xs:attribute>
    <xs:attribute name="formenctype" type="enctype_formenctype"/>    
    <xs:attribute name="formmethod" type="method_formmethod"/>    
    <xs:attribute name="formnovalidate" type="formnovalidate_boolean"/>    
    <xs:attribute name="formtarget" type="xs:string"/>
    <xs:attribute name="name" type="xs:string"/>
    <xs:attribute name="type">
      <xs:simpleType>
        <xs:restriction base="xs:token">
          <xs:enumeration value="submit"/>
          <xs:enumeration value="reset"/>
          <xs:enumeration value="button"/>
        </xs:restriction>
      </xs:simpleType>
    </xs:attribute>
    <xs:attribute name="value" type="xs:string"/>
    <xs:attributeGroup ref="globals"/>
  </xs:complexType>
</xs:element>
  
<xs:element name="cite" type="inlines_mml_and_svg"/>

<!-- Can also be used in document head -->
<xs:element name="command">
  <xs:complexType>
    <xs:complexContent>
      <xs:extension base="empty_elem_global_attrs">
        <xs:attribute name="type">
          <xs:simpleType>
            <xs:restriction base="xs:token">
              <xs:enumeration value="command"/>
              <xs:enumeration value="checkbox"/>
              <xs:enumeration value="radio"/>
            </xs:restriction>
          </xs:simpleType>
        </xs:attribute>
        <xs:attribute name="label" use="required">
          <xs:simpleType>
            <xs:restriction base="xs:string">
              <xs:minLength value="1"/>
            </xs:restriction>
          </xs:simpleType>
        </xs:attribute>
        <xs:attribute name="icon" type="xs:anyURI"/>
        <xs:attribute name="disabled" type="disabled_boolean"/>        
        <xs:attribute name="checked" type="checked_boolean"/>        
        <!-- In HTML5 spec, "radio" attribute can only be enabled for type="radio", but can't enforce that in Schema -->
        <xs:attribute name="radiogroup" type="xs:string"/>
      </xs:extension>
    </xs:complexContent>
  </xs:complexType>
</xs:element>

<xs:element name="code" type="inlines_mml_and_svg"/>
  
<xs:element name="datalist">
  <xs:complexType>
    <xs:choice>
      <xs:group ref="inlineelements" minOccurs="0" maxOccurs="unbounded"/>
      <xs:element ref="option" minOccurs="0" maxOccurs="unbounded"/>
    </xs:choice>
    <xs:attributeGroup ref="globals"/>
  </xs:complexType>
</xs:element>
  
<!-- To simplify content model, "del" element is only allowed in inline contexts in HTMLBook -->
<xs:element name="del">
  <xs:complexType>
    <xs:complexContent>
      <xs:extension base="inlines_mml_and_svg">
        <xs:attribute name="cite" type="xs:anyURI"/>
        <xs:attribute name="datetime" type="xs:string"/>
      </xs:extension>
    </xs:complexContent>
  </xs:complexType>
</xs:element>
  
<xs:element name="dfn">
  <!-- dfn elements can have any inline children, excluding another "dfn" element -->
  <xs:complexType mixed="true">
      <xs:choice minOccurs="0" maxOccurs="unbounded">
        <!-- Yeah we're enumerating all the inline options (from "inlineelements") here minus dfn, as there's no way to exclude just one item for a group,
             and I don't want to break up the "inlineelements" group below-->
        <xs:element ref="a"/>
        <xs:element ref="abbr"/>
        <xs:element ref="b"/>
        <xs:element ref="bdi"/>
        <xs:element ref="bdo"/>
        <xs:element ref="br"/>
        <xs:element ref="button"/>
        <xs:element ref="command"/>
        <xs:element ref="cite"/>
        <xs:element ref="code"/>
        <xs:element ref="datalist"/>
        <xs:element ref="del"/>
        <xs:element ref="em"/>
        <xs:element ref="i"/>
        <xs:element ref="img"/>
        <xs:element ref="input"/>
        <xs:element ref="ins"/>
        <xs:element ref="kbd"/>
        <xs:element ref="keygen"/>  
        <xs:element ref="label"/>  
        <xs:element ref="mark"/>  
        <xs:element ref="meter"/>
        <xs:element ref="output"/>
        <xs:element ref="progress"/>
        <xs:element ref="q"/>
        <xs:element ref="ruby"/>
        <xs:element ref="s"/>
        <xs:element ref="samp"/>
        <xs:element ref="select"/>
        <xs:element ref="small"/>
        <xs:element ref="span"/>
        <xs:element ref="strong"/>
        <xs:element ref="sub"/>
        <xs:element ref="sup"/>
        <xs:element ref="textarea"/>
        <xs:element ref="time"/>
        <xs:element ref="u"/>
        <xs:element ref="var"/>
        <xs:element ref="wbr"/>
        <xs:element ref="mml:math"/>
        <xs:element ref="svg:svg"/>
      </xs:choice>
      <xs:attributeGroup ref="globals"/>
  </xs:complexType>
</xs:element>
  
<xs:element name="em" type="inlines_mml_and_svg"/>
  
<xs:element name="i" type="inlines_mml_and_svg"/>
  
<xs:element name="img">
  <xs:complexType>
    <xs:complexContent>
      <xs:extension base="empty_elem_global_attrs">
        <xs:attribute name="alt" type="xs:string"/>
        <xs:attribute name="usemap" type="hash_name"/>
        <!-- In HTML5 spec, "ismap" attr requires that img have an "a" ancestor with "href" attr, but we are not enforcing that restriction in Schema -->
        <xs:attribute name="ismap">
          <xs:simpleType>
            <xs:restriction base="xs:token">
              <xs:pattern value="([Ii][Ss][Mm][Aa][Pp])?"></xs:pattern>
            </xs:restriction>
          </xs:simpleType>
        </xs:attribute>
        <xs:attribute name="src" use="required" type="xs:anyURI"/>
        <xs:attribute name="width" type="xs:string"/>
        <xs:attribute name="height" type="xs:string"/>
      </xs:extension>
    </xs:complexContent>
  </xs:complexType>
</xs:element>
  
<xs:element name="input">
  <xs:complexType>
    <xs:complexContent>
      <xs:extension base="empty_elem_global_attrs">
        <xs:attribute name="accept" type="xs:NMTOKENS"/>
        <xs:attribute name="alt" type="xs:string"/>
        <xs:attribute name="autocomplete" type="on_off"/>
        <xs:attribute name="autofocus" type="autofocus_boolean"/>
        <xs:attribute name="checked" type="checked_boolean"/>
        <xs:attribute name="dirname" type="xs:string"/>
        <xs:attribute name="disabled" type="disabled_boolean"/>
        <!-- form attribute must refer to ID of a <form> element, but we're just checking that it's an IDREF -->
        <xs:attribute name="form" type="xs:IDREF"/>
        <xs:attribute name="formaction" type="xs:anyURI"/>
        <xs:attribute name="formenctype" type="enctype_formenctype"/>
        <xs:attribute name="formmethod" type="method_formmethod"/>
        <xs:attribute name="formnovalidate" type="formnovalidate_boolean"/>
        <xs:attribute name="formtarget" type="xs:string"/>
        <xs:attribute name="height" type="xs:string"/>
        <!-- "list" attr must refer to the id attr of a "datalist" element, but here we just check that it's an IDREF -->
        <xs:attribute name="list" type="xs:IDREF"/>
        <xs:attribute name="max" type="xs:string"/>
        <xs:attribute name="maxlength" type="positive_int"/>
        <xs:attribute name="min" type="xs:string"/>
        <xs:attribute name="multiple" type="multiple_boolean"/>        
        <xs:attribute name="name">
          <xs:simpleType>
            <xs:restriction base="xs:string">
              <xs:minLength value="1"/>
            </xs:restriction>
          </xs:simpleType>
        </xs:attribute>
        <xs:attribute name="pattern" type="xs:string"/>
        <xs:attribute name="placeholder" type="xs:string"/>
        <xs:attribute name="readonly" type="readonly_boolean"/>        
        <xs:attribute name="required" type="required_boolean"/>        
        <xs:attribute name="size" type="positive_int"/>
        <xs:attribute name="src" type="xs:anyURI"/>
        <xs:attribute name="step">
          <xs:simpleType>
            <xs:restriction base="xs:float">
              <xs:minExclusive value="0"/>
            </xs:restriction>
          </xs:simpleType>
        </xs:attribute>
        <xs:attribute name="type">
          <xs:simpleType>
            <xs:restriction base="xs:token">
              <xs:enumeration value="hidden"/>
              <xs:enumeration value="text"/>
              <xs:enumeration value="search"/>
              <xs:enumeration value="tel"/>
              <xs:enumeration value="url"/>
              <xs:enumeration value="email"/>
              <xs:enumeration value="password"/>
              <xs:enumeration value="datetime"/>
              <xs:enumeration value="date"/>
              <xs:enumeration value="month"/>
              <xs:enumeration value="week"/>
              <xs:enumeration value="time"/>
              <xs:enumeration value="datetime-local"/>
              <xs:enumeration value="number"/>
              <xs:enumeration value="range"/>
              <xs:enumeration value="color"/>
              <xs:enumeration value="checkbox"/>
              <xs:enumeration value="radio"/>
              <xs:enumeration value="file"/>
              <xs:enumeration value="submit"/>
              <xs:enumeration value="image"/>
              <xs:enumeration value="reset"/>
              <xs:enumeration value="button"/>
            </xs:restriction>
          </xs:simpleType>
        </xs:attribute>
        <xs:attribute name="value" type="xs:string"/>
        <xs:attribute name="width" type="xs:string"/>
      </xs:extension>
    </xs:complexContent>
  </xs:complexType>
</xs:element>
  
<!-- To simplify content model, "ins" element is only allowed in inline contexts in HTMLBook -->
<xs:element name="ins">
  <xs:complexType>
    <xs:complexContent>
      <xs:extension base="inlines_mml_and_svg">
        <xs:attribute name="cite" type="xs:anyURI"/>
        <xs:attribute name="datetime" type="xs:string"/>
      </xs:extension>
    </xs:complexContent>
  </xs:complexType>
</xs:element>

<xs:element name="kbd" type="inlines_mml_and_svg"/>

<xs:element name="keygen">
  <xs:complexType>
    <xs:complexContent>
      <xs:extension base="empty_elem_global_attrs">
        <xs:attribute name="autofocus" type="autofocus_boolean"/>
        <xs:attribute name="challenge" type="xs:string"/>
        <xs:attribute name="disabled" type="disabled_boolean"/>
        <!-- form attribute must refer to ID of a <form> element, but we're just checking that it's an IDREF -->
        <xs:attribute name="form" type="xs:IDREF"/>
        <xs:attribute name="keytype">
          <xs:simpleType>
            <xs:restriction base="xs:token">
              <!-- HTML5 spec indicates just one enumerated value -->
              <xs:enumeration value="rsa"/>
            </xs:restriction>
          </xs:simpleType>  
        </xs:attribute>
        <xs:attribute name="name" type="xs:string"/>
      </xs:extension>
    </xs:complexContent>
  </xs:complexType>
</xs:element>
  
<xs:element name="label">
  <!-- label elements can have any inline children, excluding another "label" element -->
  <xs:complexType mixed="true">
      <xs:choice minOccurs="0" maxOccurs="unbounded">
        <!-- Yeah we're enumerating all the inline options (from "inlineelements") here minus label, as there's no way to exclude just one item for a group,
             and I don't want to break up the "inlineelements" group below-->
        <xs:element ref="a"/>
        <xs:element ref="abbr"/>
        <xs:element ref="b"/>
        <xs:element ref="bdi"/>
        <xs:element ref="bdo"/>
        <xs:element ref="br"/>
        <xs:element ref="button"/>
        <xs:element ref="command"/>
        <xs:element ref="cite"/>
        <xs:element ref="code"/>
        <xs:element ref="datalist"/>
        <xs:element ref="del"/>
        <xs:element ref="dfn"/>
        <xs:element ref="em"/>
        <xs:element ref="i"/>
        <xs:element ref="img"/>
        <xs:element ref="input"/>
        <xs:element ref="ins"/>
        <xs:element ref="kbd"/>
        <xs:element ref="keygen"/>
        <xs:element ref="mark"/>  
        <xs:element ref="meter"/>
        <xs:element ref="output"/>
        <xs:element ref="progress"/>
        <xs:element ref="q"/>
        <xs:element ref="ruby"/>
        <xs:element ref="s"/>
        <xs:element ref="samp"/>
        <xs:element ref="select"/>
        <xs:element ref="small"/>
        <xs:element ref="span"/>
        <xs:element ref="strong"/>
        <xs:element ref="sub"/>
        <xs:element ref="sup"/>
        <xs:element ref="textarea"/>
        <xs:element ref="time"/>
        <xs:element ref="u"/>
        <xs:element ref="var"/>
        <xs:element ref="wbr"/>
        <xs:element ref="mml:math"/>
        <xs:element ref="svg:svg"/>
      </xs:choice>
      <xs:attribute name="for" type="xs:IDREF"/>
      <xs:attribute name="form" type="xs:IDREF"/>
      <xs:attributeGroup ref="globals"/>
  </xs:complexType>
</xs:element>
  
<xs:element name="mark" type="inlines_mml_and_svg"/>
  
<xs:element name="meter">
  <!-- meter elements can have any inline children, excluding another "meter" element -->
  <xs:complexType mixed="true">
      <xs:choice minOccurs="0" maxOccurs="unbounded">
        <!-- Yeah we're enumerating all the inline options (from "inlineelements") here minus meter, as there's no way to exclude just one item for a group,
             and I don't want to break up the "inlineelements" group below-->
        <xs:element ref="a"/>
        <xs:element ref="abbr"/>
        <xs:element ref="b"/>
        <xs:element ref="bdi"/>
        <xs:element ref="bdo"/>
        <xs:element ref="br"/>
        <xs:element ref="button"/>
        <xs:element ref="command"/>
        <xs:element ref="cite"/>
        <xs:element ref="code"/>
        <xs:element ref="datalist"/>
        <xs:element ref="del"/>
        <xs:element ref="dfn"/>
        <xs:element ref="em"/>
        <xs:element ref="i"/>
        <xs:element ref="img"/>
        <xs:element ref="input"/>
        <xs:element ref="ins"/>
        <xs:element ref="label"/>
        <xs:element ref="kbd"/>
        <xs:element ref="keygen"/>
        <xs:element ref="mark"/>
        <xs:element ref="output"/>
        <xs:element ref="progress"/>
        <xs:element ref="q"/>
        <xs:element ref="ruby"/>
        <xs:element ref="s"/>
        <xs:element ref="samp"/>
        <xs:element ref="select"/>
        <xs:element ref="small"/>
        <xs:element ref="span"/>
        <xs:element ref="strong"/>
        <xs:element ref="sub"/>
        <xs:element ref="sup"/>
        <xs:element ref="textarea"/>
        <xs:element ref="time"/>
        <xs:element ref="u"/>
        <xs:element ref="var"/>
        <xs:element ref="wbr"/>
        <xs:element ref="mml:math"/>
        <xs:element ref="svg:svg"/>
      </xs:choice>
      <xs:attribute name="form" type="xs:IDREF"/>
      <xs:attribute name="high" type="xs:float"/>
      <xs:attribute name="low" type="xs:float"/>
      <xs:attribute name="max" type="xs:float"/>
      <xs:attribute name="min" type="xs:float"/>
      <xs:attribute name="optimum" type="xs:float"/>
      <xs:attribute name="value" type="xs:float"/>
      <xs:attributeGroup ref="globals"/>
  </xs:complexType>
</xs:element>
  
<xs:element name="output">
  <xs:complexType mixed="true">
    <xs:complexContent>
      <xs:extension base="inlines_mml_and_svg">
        <!-- output element has a few additional attributes -->
        <xs:attribute name="for" type="xs:IDREF"/>
        <xs:attribute name="form" type="xs:IDREF"/>
        <xs:attribute name="name" type="nonemptystring"/>
      </xs:extension>
    </xs:complexContent>
  </xs:complexType>
</xs:element>
  
<xs:element name="progress">
  <!-- progress elements can have any inline children, excluding another "progress" element -->
  <xs:complexType mixed="true">
    <xs:choice minOccurs="0" maxOccurs="unbounded">
      <!-- Yeah we're enumerating all the inline options (from "inlineelements") here minus progress, as there's no way to exclude just one item for a group,
           and I don't want to break up the "inlineelements" group below-->
      <xs:element ref="a"/>
      <xs:element ref="abbr"/>
      <xs:element ref="b"/>
      <xs:element ref="bdi"/>
      <xs:element ref="bdo"/>
      <xs:element ref="br"/>
      <xs:element ref="button"/>
      <xs:element ref="command"/>
      <xs:element ref="cite"/>
      <xs:element ref="code"/>
      <xs:element ref="datalist"/>
      <xs:element ref="del"/>
      <xs:element ref="dfn"/>
      <xs:element ref="em"/>
      <xs:element ref="i"/>
      <xs:element ref="img"/>
      <xs:element ref="input"/>
      <xs:element ref="ins"/>
      <xs:element ref="label"/>
      <xs:element ref="kbd"/>
      <xs:element ref="keygen"/>
      <xs:element ref="mark"/>
      <xs:element ref="meter"/>
      <xs:element ref="output"/>
      <xs:element ref="q"/>
      <xs:element ref="ruby"/>
      <xs:element ref="s"/>
      <xs:element ref="samp"/>
      <xs:element ref="select"/>
      <xs:element ref="small"/>
      <xs:element ref="span"/>
      <xs:element ref="strong"/>
      <xs:element ref="sub"/>
      <xs:element ref="sup"/>
      <xs:element ref="textarea"/>
      <xs:element ref="time"/>
      <xs:element ref="u"/>
      <xs:element ref="var"/>
      <xs:element ref="wbr"/>
      <xs:element ref="mml:math"/>
      <xs:element ref="svg:svg"/>
    </xs:choice>
    <xs:attribute name="form" type="xs:IDREF"/>
    <xs:attribute name="max" type="xs:float"/>
    <xs:attribute name="value" type="xs:float"/>
    <xs:attributeGroup ref="globals"/>
  </xs:complexType>
</xs:element>

<xs:element name="q">
  <xs:complexType mixed="true">
    <xs:complexContent>
      <xs:extension base="inlines_mml_and_svg">
        <xs:attribute name="cite" type="xs:anyURI"/>
      </xs:extension>
    </xs:complexContent>
  </xs:complexType>
</xs:element>
  
<xs:element name="ruby">
  <xs:complexType mixed="true">
    <xs:complexContent>
      <xs:extension base="inlines_mml_and_svg">
          <xs:choice>
            <xs:element ref="rt"/>
            <xs:sequence>
              <xs:element ref="rp"/>
              <xs:element ref="rt"/>
              <xs:element ref="rp"/>
            </xs:sequence>
          </xs:choice>
      </xs:extension>
    </xs:complexContent>
  </xs:complexType>
</xs:element>
  
<xs:element name="s" type="inlines_mml_and_svg"/>
  
<xs:element name="samp" type="inlines_mml_and_svg"/>

<xs:element name="select">
  <xs:complexType>
    <xs:choice>
      <xs:element ref="option" minOccurs="0" maxOccurs="unbounded"/>
      <xs:element ref="optgroup" minOccurs="0" maxOccurs="unbounded"/>
    </xs:choice>
    <xs:attribute name="autofocus" type="autofocus_boolean"/>
    <xs:attribute name="disabled" type="disabled_boolean"/>
    <!-- form attribute must refer to ID of a <form> element, but we're just checking that it's an IDREF -->
    <xs:attribute name="form" type="xs:IDREF"/>
    <xs:attribute name="multiple" type="multiple_boolean"/>
    <xs:attribute name="name">
      <xs:simpleType>
        <xs:restriction base="xs:string">
          <xs:minLength value="1"/>
        </xs:restriction>
      </xs:simpleType>
    </xs:attribute>
    <xs:attribute name="required" type="required_boolean"/>
    <xs:attribute name="size" type="positive_int"/>
    <xs:attributeGroup ref="globals"/>
  </xs:complexType>
</xs:element>
  
<xs:element name="small" type="inlines_mml_and_svg"/>
  
<xs:element name="span" type="inlines_mml_and_svg"/>
  
<xs:element name="strong" type="inlines_mml_and_svg"/>
  
<xs:element name="sub" type="inlines_mml_and_svg"/>
  
<xs:element name="sup" type="inlines_mml_and_svg"/>
  
<xs:element name="textarea">
  <xs:complexType mixed="true">
    <xs:attribute name="autofocus" type="autofocus_boolean"/>
    <xs:attribute name="cols" type="positive_int"/>
    <xs:attribute name="dirname" type="xs:string"/>
    <xs:attribute name="disabled" type="disabled_boolean"/>
    <!-- form attribute must refer to ID of a <form> element, but we're just checking that it's an IDREF -->
    <xs:attribute name="form" type="xs:IDREF"/>
    <xs:attribute name="maxlength" type="positive_int"/>
    <xs:attribute name="name">
      <xs:simpleType>
        <xs:restriction base="xs:string">
          <xs:minLength value="1"/>
        </xs:restriction>
      </xs:simpleType>
    </xs:attribute>
    <xs:attribute name="placeholder" type="xs:string"/>
    <xs:attribute name="readonly" type="readonly_boolean"/>
    <xs:attribute name="required" type="required_boolean"/>
    <xs:attribute name="rows" type="positive_int"/>
    <xs:attribute name="wrap">
      <xs:simpleType>
        <xs:restriction base="xs:token">
          <xs:enumeration value="soft"/>
          <xs:enumeration value="hard"/>
        </xs:restriction>
      </xs:simpleType>
    </xs:attribute>
    <xs:attributeGroup ref="globals"/>
  </xs:complexType>
</xs:element>
  
<xs:element name="time">
  <!-- time elements can have any inline children, excluding another "time" element -->
  <xs:complexType mixed="true">
    <xs:choice minOccurs="0" maxOccurs="unbounded">
      <!-- Yeah we're enumerating all the inline options (from "inlineelements") here minus time, as there's no way to exclude just one item for a group,
           and I don't want to break up the "inlineelements" group below-->
      <xs:element ref="a"/>
      <xs:element ref="abbr"/>
      <xs:element ref="b"/>
      <xs:element ref="bdi"/>
      <xs:element ref="bdo"/>
      <xs:element ref="br"/>
      <xs:element ref="button"/>
      <xs:element ref="command"/>
      <xs:element ref="cite"/>
      <xs:element ref="code"/>
      <xs:element ref="datalist"/>
      <xs:element ref="del"/>
      <xs:element ref="dfn"/>
      <xs:element ref="em"/>
      <xs:element ref="i"/>
      <xs:element ref="img"/>
      <xs:element ref="input"/>
      <xs:element ref="ins"/>
      <xs:element ref="label"/>
      <xs:element ref="kbd"/>
      <xs:element ref="keygen"/>
      <xs:element ref="mark"/>
      <xs:element ref="meter"/>
      <xs:element ref="output"/>
      <xs:element ref="progress"/>
      <xs:element ref="q"/>
      <xs:element ref="ruby"/>
      <xs:element ref="s"/>
      <xs:element ref="samp"/>
      <xs:element ref="select"/>
      <xs:element ref="small"/>
      <xs:element ref="span"/>
      <xs:element ref="strong"/>
      <xs:element ref="sub"/>
      <xs:element ref="sup"/>
      <xs:element ref="textarea"/>
      <xs:element ref="u"/>
      <xs:element ref="var"/>
      <xs:element ref="wbr"/>
      <xs:element ref="mml:math"/>
      <xs:element ref="svg:svg"/>
    </xs:choice>
    <xs:attribute name="pubdate">
      <xs:simpleType>
        <xs:restriction base="xs:string">
          <xs:pattern value="([Pp][Uu][Bb][Dd][Aa][Tt][Ee])?"/>
        </xs:restriction>
      </xs:simpleType>
    </xs:attribute>
    <xs:attribute name="datetime" type="xs:string"/>
    <xs:attributeGroup ref="globals"/>
  </xs:complexType>
</xs:element>
  
<xs:element name="u" type="inlines_mml_and_svg"/>
  
<xs:element name="var" type="inlines_mml_and_svg"/>
  
<xs:element name="wbr" type="empty_elem_global_attrs"/>
    
<!-- Miscellaneous elements -->
<xs:element name="area">
  <xs:complexType>
    <xs:complexContent>
      <xs:extension base="empty_elem_global_attrs">
        <xs:attribute name="alt" type="xs:string"/>
        <xs:attribute name="coords">
          <xs:simpleType>
            <xs:restriction base="xs:string">
              <!-- Regex for string of comma-separated numbers -->
              <!-- Yes, this'll match a string that ends in a comma,
                   but close enough for validation purposes, given that XML Schema doesn't support lookaheads -->
              <xs:pattern value="[0-9][0-9,]*"/>
            </xs:restriction>
          </xs:simpleType>
        </xs:attribute>
        <xs:attribute name="shape">
          <xs:simpleType>
            <xs:restriction base="xs:token">
              <xs:enumeration value="circle"/>
              <xs:enumeration value="circ"/>
              <xs:enumeration value="default"/>
              <xs:enumeration value="poly"/>
              <xs:enumeration value="polygon"/>
              <xs:enumeration value="rect"/>
              <xs:enumeration value="rectangle"/>
            </xs:restriction>
          </xs:simpleType>
        </xs:attribute>
        <xs:attribute name="href" type="xs:anyURI"/>
        <xs:attribute name="target" type="xs:string"/>
        <xs:attribute name="rel">
          <xs:simpleType>
            <xs:restriction base="xs:string">
              <!-- Ugly regex alert -->
              <xs:pattern value="(alternate|author|bookmark|external|help|icon|license|next|nofollow|noreferrer|pingback|prefetch|prev|search|sidebar|stylesheet|tag)( (alternate|author|bookmark|external|help|icon|license|next|nofollow|noreferrer|pingback|prefetch|prev|search|sidebar|stylesheet|tag))*"/>
            </xs:restriction>
          </xs:simpleType>
        </xs:attribute>
        <xs:attribute name="media" type="xs:string"/>
        <xs:attribute name="hreflang" type="xs:language"/>
        <xs:attribute name="type" type="xs:string"/>
      </xs:extension>
    </xs:complexContent>
  </xs:complexType>
</xs:element>
  
<xs:element name="caption" type="caption"/>
  
<xs:element name="col">
  <xs:complexType>
    <xs:complexContent>
      <xs:extension base="empty_elem_global_attrs">
        <xs:attribute name="span" type="xs:int"/>
      </xs:extension>
    </xs:complexContent>
  </xs:complexType>
</xs:element>
  
<xs:element name="colgroup">
  <!-- Technically, colgroup requires an either/or situation, where if there is a span attribute, there should be no <col> children.
       Not possible to represent this in XML Schema -->
  <xs:complexType>
    <xs:sequence>
      <xs:element ref="col" minOccurs="0" maxOccurs="unbounded"/>
    </xs:sequence>
    <xs:attribute name="span" type="xs:int"/>
    <xs:attributeGroup ref="globals"/>
  </xs:complexType>
</xs:element>
  
<xs:element name="dd" type="block_xor_inline_children"/>

<xs:element name="dt" type="inlines_mml_and_svg"/>

<xs:element name="figcaption" type="caption"/>
  
<xs:element name="legend" type="inlines_mml_and_svg"/>
  
<xs:element name="li" type="block_xor_inline_children"/>
  
<xs:element name="optgroup">
  <xs:complexType>
    <xs:sequence>
      <xs:element ref="option" minOccurs="0" maxOccurs="unbounded"/>
    </xs:sequence>
    <xs:attribute name="disabled" type="disabled_boolean"/>
    <xs:attribute name="label" type="xs:string" use="required"/>
    <xs:attributeGroup ref="globals"/>
  </xs:complexType>
</xs:element>
  
<xs:element name="option">
  <xs:complexType mixed="true">
    <xs:complexContent>
      <xs:extension base="empty_elem_global_attrs">
        <xs:attribute name="disabled" type="disabled_boolean"/>        
        <xs:attribute name="label" type="xs:string"/>
        <xs:attribute name="selected">
          <xs:simpleType>
            <xs:restriction base="xs:token">
              <xs:pattern value="([Ss][Ee][Ll][Ee][Cc][Tt][Ee][Dd])?"/>
            </xs:restriction>
          </xs:simpleType>
        </xs:attribute>
        <xs:attribute name="value" type="xs:string"/>
      </xs:extension>
    </xs:complexContent>
  </xs:complexType>
</xs:element>
  
<xs:element name="param">
  <xs:complexType>
    <xs:complexContent>
      <xs:extension base="empty_elem_global_attrs">
        <xs:attribute name="name" type="xs:string" use="required"/>
        <xs:attribute name="value" type="xs:string" use="required"/>        
      </xs:extension>
    </xs:complexContent>
  </xs:complexType>
</xs:element>
  
<xs:element name="rp" type="inlines_mml_and_svg"/>
  
<xs:element name="rt" type="inlines_mml_and_svg"/>
  
<xs:element name="source">
  <xs:complexType>
    <xs:complexContent>
      <xs:extension base="empty_elem_global_attrs">
        <xs:attribute name="media" type="xs:string"/>
        <xs:attribute name="src" type="xs:anyURI" use="required"/>
        <xs:attribute name="type" type="xs:string"/>
      </xs:extension>
    </xs:complexContent>
  </xs:complexType>  
</xs:element>

<xs:element name="summary" type="inlines_mml_and_svg"/>
  
<xs:element name="tbody" type="tablegrouping"/>
  
<xs:element name="td">
  <xs:complexType>
    <xs:complexContent>
      <xs:extension base="block_xor_inline_children">
        <xs:attributeGroup ref="tablecellattributes"/>
      </xs:extension>
    </xs:complexContent>
  </xs:complexType>
</xs:element>
  
<xs:element name="th">
  <xs:complexType>
    <xs:complexContent>
      <xs:extension base="inlines_mml_and_svg">
        <xs:attributeGroup ref="tablecellattributes"/>
        <xs:attribute name="scope">
          <xs:simpleType>
            <xs:restriction base="xs:token">
              <xs:enumeration value="auto"/>
              <xs:enumeration value="col"/>
              <xs:enumeration value="colgroup"/>
              <xs:enumeration value="row"/>
              <xs:enumeration value="rowgroup"/>
            </xs:restriction>
          </xs:simpleType>
        </xs:attribute>
      </xs:extension>
    </xs:complexContent>
  </xs:complexType>
</xs:element>

<xs:element name="thead" type="tablegrouping"/>
  
<xs:element name="tfoot" type="tablegrouping"/>
  
<xs:element name="tr">
  <xs:complexType>
    <xs:choice>
      <xs:element ref="td" minOccurs="0" maxOccurs="unbounded"/>
      <xs:element ref="th" minOccurs="0" maxOccurs="unbounded"/>
    </xs:choice>
    <xs:attributeGroup ref="globals"/>
  </xs:complexType>
</xs:element>
  
<xs:element name="track">
  <xs:complexType>
    <xs:complexContent>
      <xs:extension base="empty_elem_global_attrs">
        <xs:attribute name="default">
          <xs:simpleType>
            <xs:restriction base="xs:token">
              <xs:pattern value="([Dd][Ee][Ff][Aa][Uu][Ll][Tt])?"/>
            </xs:restriction>
          </xs:simpleType>
        </xs:attribute>
        <xs:attribute name="kind">
          <xs:simpleType>
            <xs:restriction base="xs:token">
              <xs:enumeration value="captions"/>
              <xs:enumeration value="chapters"/>
              <xs:enumeration value="descriptions"/>
              <xs:enumeration value="metadata"/>
              <xs:enumeration value="subtitles"/>
            </xs:restriction>
          </xs:simpleType>
        </xs:attribute>
        <xs:attribute name="label" type="xs:string"/>
        <xs:attribute name="src" type="xs:anyURI"/>
        <xs:attribute name="srclang" type="xs:language"/>
      </xs:extension>
    </xs:complexContent>
  </xs:complexType>
</xs:element>

<!-- Heading elements -->
<xs:element name="h1" type="inlines_mml_and_svg"/>

<xs:element name="h2" type="inlines_mml_and_svg"/>

<xs:element name="h3" type="inlines_mml_and_svg"/>
  
<xs:element name="h4" type="inlines_mml_and_svg"/>
  
<xs:element name="h5" type="inlines_mml_and_svg"/>
  
<xs:element name="h6" type="inlines_mml_and_svg"/>
  
  
<!-- Global simple type definitions; see also global complex types section -->

<!-- For data-type attribute on book division <sections>, except part -->
<xs:simpleType name="bookmaindivtype">
  <xs:restriction base="xs:string">
    <xs:enumeration value="acknowledgments"/>
    <xs:enumeration value="afterword"/>
    <xs:enumeration value="appendix"/>
    <xs:enumeration value="bibliography"/>
    <xs:enumeration value="chapter"/>
    <xs:enumeration value="colophon"/>
    <xs:enumeration value="conclusion"/>
    <xs:enumeration value="copyright-page"/>
    <xs:enumeration value="dedication"/>
    <xs:enumeration value="foreword"/>
    <xs:enumeration value="glossary"/>
    <xs:enumeration value="halftitlepage"/>
    <xs:enumeration value="index"/>
    <xs:enumeration value="introduction"/>
    <xs:enumeration value="preface"/>
    <xs:enumeration value="titlepage"/>
    <xs:enumeration value="toc"/>
  </xs:restriction>
</xs:simpleType>
  
<!-- Used for attributes that require a nonempty string (e.g., "name" attribute on <output> -->
<xs:simpleType name="nonemptystring">
  <xs:restriction base="xs:string">
    <xs:pattern value=".+"/>
  </xs:restriction>
</xs:simpleType>
  
<!-- Used for positive integers -->
<xs:simpleType name="positive_int">
  <xs:restriction base="xs:integer">
    <xs:minExclusive value="0"/>
  </xs:restriction>
</xs:simpleType>
  
<!-- For types of subheadings: subtitle, author attributions, etc. -->
<!-- ToDo: Add additional types as required -->
<xs:simpleType name="subheadingtype">
  <xs:restriction base="xs:string">
    <xs:enumeration value="subtitle"/>
    <xs:enumeration value="author"/>
  </xs:restriction>
</xs:simpleType>
  
<!-- Restrict boolean type to only allow "true", "false", or empty string -->
<xs:simpleType name="true_false">
  <xs:restriction base="xs:token">
    <xs:enumeration value="true"/>
    <xs:enumeration value="false"/>
    <xs:enumeration value=""/>
  </xs:restriction>
</xs:simpleType>
  
<!-- For attributes enumerated as on/off (e.g., autocomplete) -->
<xs:simpleType name="on_off">
  <xs:restriction base="xs:token">
    <xs:enumeration value="on"/>
    <xs:enumeration value="off"/>
  </xs:restriction>
</xs:simpleType>
  
<!--- autofocus boolean -->
<xs:simpleType name="autofocus_boolean">
  <xs:restriction base="xs:token">
    <xs:pattern value="([Aa][Uu][Tt][Oo][Ff][Oo][Cc][Uu][Ss])?"/>
  </xs:restriction>
</xs:simpleType>
  
<!-- checked boolean -->
<xs:simpleType name="checked_boolean">
  <xs:restriction base="xs:token">
    <xs:pattern value="([Cc][Hh][Ee][Cc][Kk][Ee][Dd])?"/>
  </xs:restriction>
</xs:simpleType>
  
<!-- disabled boolean -->
<xs:simpleType name="disabled_boolean">
  <xs:restriction base="xs:token">
    <xs:pattern value="([Dd][Ii][Ss][Aa][Bb][Ll][Ee][Dd])?"/>
  </xs:restriction>
</xs:simpleType>
  
<!-- formnovalidate boolean -->
<xs:simpleType name="formnovalidate_boolean">
  <xs:restriction base="xs:token">
    <xs:pattern value="([Ff][Oo][Rr][Mm][Nn][Oo][Vv][Aa][Ll][Ii][Dd][Aa][Tt][Ee])?"></xs:pattern>
  </xs:restriction>
</xs:simpleType>
  
<!-- multiple boolean -->
<xs:simpleType name="multiple_boolean">
  <xs:restriction base="xs:token">
    <xs:pattern value="([Mm][Uu][Ll][Tt][Ii][Pp][Ll][Ee])?"></xs:pattern>
  </xs:restriction>
</xs:simpleType>
 
<!-- readonly boolean -->
<xs:simpleType name="readonly_boolean">
  <xs:restriction base="xs:token">
    <xs:pattern value="([Rr][Ee][Aa][Dd][Oo][Nn][Ll][Yy])?"></xs:pattern>
  </xs:restriction>
</xs:simpleType>
  
<!-- required boolean -->
<xs:simpleType name="required_boolean">
  <xs:restriction base="xs:token">
    <xs:pattern value="([Rr][Ee][Qq][Uu][Ii][Rr][Ee][Dd])?"/>
  </xs:restriction>
</xs:simpleType>  
  
<!-- for enctype/formenctype attributes used on form elements -->
<xs:simpleType name="enctype_formenctype">
  <xs:restriction base="xs:string">
    <xs:enumeration value="application/x-www-form-urlencoded"/>
    <xs:enumeration value="multipart/form-data"/>
    <xs:enumeration value="text/plain"/>
  </xs:restriction>
</xs:simpleType>
  
<!-- for method/formmethod attributes used on form elements -->
<xs:simpleType name="method_formmethod">
  <xs:restriction base="xs:token">
    <xs:enumeration value="get"/>
    <xs:enumeration value="post"/>
  </xs:restriction>
</xs:simpleType>
  
<!-- For hash-name references; we're just checking that string starts with #, not that the reference is actually there -->
<xs:simpleType name="hash_name">
  <xs:restriction base="xs:string">
    <xs:pattern value="#.+"/>
  </xs:restriction>
</xs:simpleType>
 
<!-- Global complex type definitions; see also global simple types section-->

<!-- Chapter/Appendix/Preface/etc. -->
<xs:complexType name="bookmaindiv">
  <xs:sequence>
    <xs:element ref="h1"/>
    <xs:element name="h2" minOccurs="0" maxOccurs="unbounded" type="subheading"/>
    <!-- Allow full set of block elements plus img elements in chapter-level sections -->
    <xs:group ref="figure_elements" minOccurs="0" maxOccurs="unbounded"/>
    <xs:element name="section" minOccurs="0" maxOccurs="unbounded" type="sect1"/>
  </xs:sequence>
  <!-- Note: special data-type attr restrictions here -->
  <xs:attribute name="data-type" use="required" type="bookmaindivtype"/>
  <xs:attributeGroup ref="globals"/>
</xs:complexType>

<!-- Parts -->
<xs:complexType name="bookpart">
  <xs:sequence>
    <xs:element ref="h1"/>
    <xs:element name="h2" minOccurs="0" maxOccurs="unbounded" type="subheading"/>
    <!-- Allow full set of block elements plus img elements in part divs -->
    <xs:group ref="figure_elements" minOccurs="0" maxOccurs="unbounded"/>
    <xs:element name="section" maxOccurs="unbounded" type="bookmaindiv"/>
  </xs:sequence>
  <!-- Note: special data-type attr restrictions here -->
  <xs:attribute name="data-type" use="required" fixed="part"/>
  <xs:attributeGroup ref="globals"/>
</xs:complexType>
  
<!-- Sect1s -->
<xs:complexType name="sect1">
  <xs:sequence>
    <xs:element ref="h1"/>
    <xs:element name="h2" minOccurs="0" maxOccurs="unbounded" type="subheading"/>
    <!-- Allow full set of block elements plus img elements in sect1s -->
    <xs:group ref="figure_elements" minOccurs="0" maxOccurs="unbounded"/>
    <xs:element name="section" minOccurs="0" maxOccurs="unbounded" type="sect2"/>
  </xs:sequence>
  <!-- Note: special data-type attr restrictions here -->
  <xs:attribute name="data-type" use="required" fixed="sect1"/>
  <xs:attributeGroup ref="globals"/>
</xs:complexType>

<!-- Sect2s -->
<xs:complexType name="sect2">
  <xs:sequence>
    <xs:element ref="h2"/>
    <xs:element name="h3" minOccurs="0" maxOccurs="unbounded" type="subheading"/>
    <!-- Allow full set of block elements plus img elements in sect2s -->
    <xs:group ref="figure_elements" minOccurs="0" maxOccurs="unbounded"/>
    <xs:element name="section" minOccurs="0" maxOccurs="unbounded" type="sect3"/>
  </xs:sequence>
  <!-- Note: special data-type attr restrictions here -->
  <xs:attribute name="data-type" use="required" fixed="sect2"/>
  <xs:attributeGroup ref="globals"/>
</xs:complexType>
  
<!-- Sect3s -->
<xs:complexType name="sect3">
  <xs:sequence>
    <xs:element ref="h3"/>
    <xs:element name="h4" minOccurs="0" maxOccurs="unbounded" type="subheading"/>
    <!-- Allow full set of block elements plus img elements in sect3s -->
    <xs:group ref="figure_elements" minOccurs="0" maxOccurs="unbounded"/>
    <xs:element name="section" minOccurs="0" maxOccurs="unbounded" type="sect4"/>
  </xs:sequence>
  <!-- Note: special data-type attr restrictions here -->
  <xs:attribute name="data-type" use="required" fixed="sect3"/>
  <xs:attributeGroup ref="globals"/>
</xs:complexType>
  
<!-- Sect4s -->
<xs:complexType name="sect4">
  <xs:sequence>
    <xs:element ref="h4"/>
    <xs:element name="h5" minOccurs="0" maxOccurs="unbounded" type="subheading"/>
    <!-- Allow full set of block elements plus img elements in sect4s -->
    <xs:group ref="figure_elements" minOccurs="0" maxOccurs="unbounded"/>
    <xs:element name="section" minOccurs="0" maxOccurs="unbounded" type="sect5"/>
  </xs:sequence>
  <!-- Note: special data-type attr restrictions here -->
  <xs:attribute name="data-type" use="required" fixed="sect4"/>
  <xs:attributeGroup ref="globals"/>
</xs:complexType>
  
<!-- Sect5 -->
<xs:complexType name="sect5">
  <xs:sequence>
    <xs:element ref="h5"/>
    <xs:element name="h6" minOccurs="0" maxOccurs="unbounded" type="subheading"/>
    <!-- Allow full set of block elements plus img elements in sect5s -->
    <xs:group ref="figure_elements" minOccurs="0" maxOccurs="unbounded"/>
  </xs:sequence>
  <!-- Note: special data-type attr restrictions here -->
  <xs:attribute name="data-type" use="required" fixed="sect5"/>
  <xs:attributeGroup ref="globals"/>
</xs:complexType>
  
<!-- Sidebar; primarily for <aside> -->
<xs:complexType name="sidebar">
  <xs:sequence>
    <xs:element ref="h5" minOccurs="0"/> <!-- Unlike other sections, sidebar titles are optional -->
    <xs:group ref="figure_elements" minOccurs="0" maxOccurs="unbounded"/>
  </xs:sequence>
  <!-- ToDo: require data-type attr restriction of "sidebar" here? -->
  <xs:attributeGroup ref="globals"/>
</xs:complexType>
  
<!-- Subheadings: support subtitles, author attributions, etc. -->
<!-- ToDo: Continue to flesh out as necessary -->
<xs:complexType name="subheading" mixed="true">
  <xs:sequence>
    <xs:group ref="inlines_plus_mml_and_svg" minOccurs="0" maxOccurs="unbounded"/>
  </xs:sequence>
  <!-- Note: special data-type attr restrictions here -->
  <xs:attribute name="data-type" use="required" type="subheadingtype"/>
  <xs:attributeGroup ref="globals"/>
</xs:complexType>
 
<!-- Custom types for Nav Document (following EPUB 3 spec; see http://www.idpf.org/epub/30/spec/epub30-contentdocs.html#sec-xhtml-nav) -->
<xs:complexType name="nav_doc_ol">
  <xs:sequence>
    <xs:element name="li" type="nav_doc_li" minOccurs="0" maxOccurs="unbounded"/>
  </xs:sequence>
  <xs:attributeGroup ref="ol_attrs"/>
  <xs:attributeGroup ref="globals"/>
</xs:complexType>
  
<xs:complexType name="nav_doc_li" mixed="true">
  <xs:choice>
    <xs:element ref="span"/>
    <xs:sequence>
      <xs:element ref="a"/>
      <xs:element name="ol" minOccurs="0" type="nav_doc_ol"/>
    </xs:sequence>
  </xs:choice>
  <xs:attributeGroup ref="globals"/>
</xs:complexType>
  
<!-- General handling for elements that can accept only inline children -->
<xs:complexType name="inlines_mml_and_svg" mixed="true">
  <xs:sequence>
    <xs:group ref="inlines_plus_mml_and_svg" minOccurs="0" maxOccurs="unbounded"/>
  </xs:sequence>
  <xs:attributeGroup ref="globals"/>
</xs:complexType>
  
<!-- General handling for elements that can accept either block children or inline children (not both)-->
<xs:complexType name="block_xor_inline_children" mixed="true">
  <xs:choice>
    <xs:group ref="blockelements" minOccurs="0" maxOccurs="unbounded"/>
    <xs:group ref="inlineelements" minOccurs="0" maxOccurs="unbounded"/>
  </xs:choice>
  <xs:attributeGroup ref="globals"/>
</xs:complexType>

<!-- Type for no restrictions on child content -->
<xs:complexType name="any_elems_attrs" mixed="true">
  <xs:sequence minOccurs="0" maxOccurs="unbounded">
    <xs:any processContents="lax"/>
  </xs:sequence>
  <xs:attributeGroup ref="globals"/>
</xs:complexType>
  
<!-- Type for empty element, with no specific attribute requirements -->
<xs:complexType name="empty_elem_global_attrs">
  <xs:attributeGroup ref="globals"/>
</xs:complexType>

<!-- Type for figure/table captions -->
<xs:complexType name="caption" mixed="true">
  <!-- Subset of block elements (<p>s or <div>s) xor inline elements-->
  <xs:choice>
    <xs:choice minOccurs="0" maxOccurs="unbounded">
      <xs:element ref="p"/>
      <xs:element ref="div"/>
    </xs:choice>
    <xs:group ref="inlines_plus_mml_and_svg" minOccurs="0" maxOccurs="unbounded"/>
  </xs:choice>
  <xs:attributeGroup ref="globals"/>
</xs:complexType>
  
<!-- Type for table group blocks: thead, tbody, and tfoot -->
<xs:complexType name="tablegrouping">
  <xs:sequence>
    <xs:element ref="tr" minOccurs="0" maxOccurs="unbounded"/>
  </xs:sequence>
  <xs:attributeGroup ref="globals"/>
</xs:complexType>
  
<!-- Global groups -->
  
<xs:group name="blockelements">
  <!-- We're defining "block elements" here as a subset of HTML5 flow content that can be children of a <section> -->
  <xs:choice>
    <xs:element ref="address"/>
    <xs:element ref="aside"/>
    <xs:element ref="audio"/>
    <xs:element ref="blockquote"/>
    <xs:element ref="canvas"/>
    <xs:element ref="details"/>
    <xs:element ref="div"/>
    <xs:element ref="dl"/>
    <xs:element ref="embed"/>
    <xs:element ref="fieldset"/>
    <xs:element ref="figure"/>
    <xs:element ref="form"/>
    <xs:element ref="hr"/>
    <xs:element ref="iframe"/>
    <xs:element ref="map"/>
    <xs:element ref="menu"/>
    <xs:element ref="object"/>
    <xs:element ref="ol"/>
    <xs:element ref="p"/>
    <xs:element ref="pre"/>
    <xs:element ref="table"/>
    <xs:element ref="ul"/>
    <xs:element ref="video"/>
    <xs:group ref="external_elements"/>
  </xs:choice>
</xs:group>

<!-- Elements from other vocabularies that can be included in HTML5: MathML and SVG -->
<xs:group name="external_elements">
  <xs:choice>
    <xs:element ref="mml:math"/>
    <xs:element ref="svg:svg"/>
  </xs:choice>
</xs:group>

<!-- Elements that can go in a figure = block elements + img -->
<xs:group name="figure_elements">
  <xs:choice>
    <xs:group ref="blockelements"/>
    <xs:element ref="img"/>
  </xs:choice>
</xs:group>
  
<!-- Elements that can go in a map = block elements + area -->
<xs:group name="map_elements">
  <xs:choice>
    <xs:group ref="blockelements"/>
    <xs:element ref="area"/>
  </xs:choice>
</xs:group>
    
<xs:group name="headings">
  <xs:choice>
    <xs:element ref="h1"/>
    <xs:element ref="h2"/>
    <xs:element ref="h3"/>
    <xs:element ref="h4"/>
    <xs:element ref="h5"/>
    <xs:element ref="h6"/>
  </xs:choice>
</xs:group>
  
<xs:group name="inlineelements">
<!-- We're defining "inline elements" here as being generally equivalent to the set of HTML5 phrasing elements: 
     those that can be children of a block element.
     These are elements that can be used *solely in an inline context* Elements that can be either inline or block 
     (e.g., <math> and <svg>) are not covered) -->
  <xs:choice>
    <xs:element ref="a"/>
    <xs:element ref="abbr"/>
    <xs:element ref="b"/>
    <xs:element ref="bdi"/>
    <xs:element ref="bdo"/>
    <xs:element ref="br"/>
    <xs:element ref="button"/>
    <xs:element ref="command"/>
    <xs:element ref="cite"/>
    <xs:element ref="code"/>
    <xs:element ref="datalist"/>
    <xs:element ref="del"/>
    <xs:element ref="dfn"/>
    <xs:element ref="em"/>
    <xs:element ref="i"/>
    <xs:element ref="input"/>
    <xs:element ref="img"/>
    <xs:element ref="ins"/>
    <xs:element ref="kbd"/>
    <xs:element ref="keygen"/>  
    <xs:element ref="label"/>  
    <xs:element ref="mark"/>  
    <xs:element ref="meter"/>
    <xs:element ref="output"/>
    <xs:element ref="progress"/>
    <xs:element ref="q"/>
    <xs:element ref="ruby"/>
    <xs:element ref="s"/>
    <xs:element ref="samp"/>
    <xs:element ref="select"/>
    <xs:element ref="small"/>
    <xs:element ref="span"/>
    <xs:element ref="strong"/>
    <xs:element ref="sub"/>
    <xs:element ref="sup"/>
    <xs:element ref="textarea"/>
    <xs:element ref="time"/>
    <xs:element ref="u"/>
    <xs:element ref="var"/>
    <xs:element ref="wbr"/>
  </xs:choice>
</xs:group>
  
<xs:group name="inlines_plus_mml_and_svg">
  <xs:choice>
    <xs:group ref="inlineelements"/>
    <xs:group ref="external_elements"/>
  </xs:choice>
</xs:group>
  
<!-- Global attribute groups -->
<!-- ToDo: Go ahead and add group for global HTML5 attributes (with exception of data- attrs),
      or just leave the xs:anyAttribute declarations to catch these? (If this is done, remove all the xs:attribute declarations for "id")-->

<!-- All globals except "dir", which is separated out because other elements have their own 'dir' requirements -->
<xs:attributeGroup name="globals_minus_dir">
  <xs:attribute name="accesskey">
    <xs:simpleType>
      <xs:restriction base="xs:NMTOKENS">
        <xs:pattern value="[^ ]( [^ ])*"></xs:pattern>
      </xs:restriction>
    </xs:simpleType>
  </xs:attribute>
  <xs:attribute name="class" type="xs:NMTOKENS"/>
  <xs:attribute name="contenteditable" type="true_false"/>
  <xs:attribute name="contextmenu" type="xs:IDREF"/>
  <xs:attribute name="draggable" type="true_false"/>
  <xs:attribute name="dropzone" type="xs:NMTOKENS"/>
  <xs:attribute name="hidden">
    <xs:simpleType>
      <xs:restriction base="xs:token">
        <xs:pattern value="([Hh][Ii][Dd][Dd][Ee][Nn])?"/>
      </xs:restriction>
    </xs:simpleType>
  </xs:attribute>
  <xs:attribute name="id" type="xs:ID"/>
  <xs:attribute name="lang" type="xs:language"/>
  <xs:attribute name="spellcheck" type="true_false"/>
  <xs:attribute name="style" type="xs:string"/>
  <xs:attribute name="tabindex" type="xs:integer"/>
  <xs:attribute name="title" type="xs:string"/>
  <!-- To accommodate data- attrs -->
  <xs:anyAttribute processContents="lax"/>
</xs:attributeGroup>
  
<!-- All globals, including dir -->
<xs:attributeGroup name="globals">
  <xs:attributeGroup ref="globals_minus_dir"/>
  <xs:attribute name="dir">
    <xs:simpleType>
      <xs:restriction base="xs:token">
        <xs:enumeration value="ltr"/>
        <xs:enumeration value="rtl"/>              
      </xs:restriction>
    </xs:simpleType>
  </xs:attribute>
</xs:attributeGroup>
  
<!-- Attributes used by <ol> elements -->
<xs:attributeGroup name="ol_attrs">
  <xs:attribute name="reversed">
    <xs:simpleType>
      <xs:restriction base="xs:string">
        <!-- Must be a case-insensitive match for "reversed" or empty string -->
        <xs:pattern value="([Rr][Ee][Vv][Ee][Rr][Ss][Ee][Dd])?"/>            
      </xs:restriction>
    </xs:simpleType>
  </xs:attribute>
  <xs:attribute name="start" type="xs:integer"/>
  <xs:attribute name="type">
    <xs:simpleType>
      <xs:restriction base="xs:token">
        <xs:enumeration value="1"/>
        <xs:enumeration value="a"/>
        <xs:enumeration value="A"/>
        <xs:enumeration value="i"/>
        <xs:enumeration value="I"/>
      </xs:restriction>
    </xs:simpleType>
  </xs:attribute>
</xs:attributeGroup>
  
<!-- Media attributes used by both <audio> and <video> elements -->
<xs:attributeGroup name="generalmediaattributes">
  <xs:attribute name="src" type="xs:anyURI"/>
  <xs:attribute name="preload">
    <xs:simpleType>
      <xs:restriction base="xs:token">
        <xs:enumeration value="auto"/>
        <xs:enumeration value="metadata"/>
        <xs:enumeration value="none"/>
      </xs:restriction>
    </xs:simpleType>
  </xs:attribute>
  <xs:attribute name="autoplay">
    <xs:simpleType>
      <xs:restriction base="xs:token">
        <xs:pattern value="([Aa][Uu][Tt][Oo][Pp][Ll][Aa][Yy])?"/>
      </xs:restriction>
    </xs:simpleType>
  </xs:attribute>
  <xs:attribute name="mediagroup" type="xs:string"/>
  <xs:attribute name="loop">
    <xs:simpleType>
      <xs:restriction base="xs:token">
        <xs:pattern value="([Ll][Oo][Oo][Pp])?"/>
      </xs:restriction>
    </xs:simpleType>
  </xs:attribute>
  <xs:attribute name="muted">
    <xs:simpleType>
      <xs:restriction base="xs:token">
        <xs:pattern value="([Mm][Uu][Tt][Ee][Dd])?"/>
      </xs:restriction>
    </xs:simpleType>
  </xs:attribute>
  <xs:attribute name="controls">
    <xs:simpleType>
      <xs:restriction base="xs:token">
        <xs:pattern value="([Cc][Oo][Nn][Tt][Rr][Oo][Ll][Ss])?"/>
      </xs:restriction>
    </xs:simpleType>
  </xs:attribute>
</xs:attributeGroup>
  
<xs:attributeGroup name="videomediaattributes">
  <xs:attributeGroup ref="generalmediaattributes"/>
  <xs:attribute name="poster" type="xs:anyURI"/>
  <xs:attribute name="width" type="xs:string"/>
  <xs:attribute name="height" type="xs:string"/>
</xs:attributeGroup>
  
<!-- Table cell attributes shared by both th and td (does not include th-specific element scope) -->
<xs:attributeGroup name="tablecellattributes">
  <xs:attribute name="colspan" type="positive_int"/>
  <xs:attribute name="rowspan" type="positive_int"/>
  <!-- Per HTML5 spec, each space-separated token in "headers" should be an idref pointing to
       the id on a corresponding <th> in the same table, but not enforcing this in the Schema -->
  <xs:attribute name="headers" type="xs:NMTOKENS"/>
</xs:attributeGroup>
  
</xs:schema>