XHTML Role Attribute Module

The XHTML Role Attribute defined in this specification allows the author to annotate XML Languages with machine-extractable semantic information about the purpose of an element. Use cases include accessibility, device adaptation, server-side processing, and complex data description. This attribute can be integrated into any markup language based upon XHTML Modularization [XHTMLMOD].

Status of This Document

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 latest revision of this technical report can be found in the W3C technical reports index at http://www.w3.org/TR/.

This document is a second Last Call Working Draft. It is based upon comments received against the previous draft, and also upon work done in the definition of [XHTML2]. A record of how the comments from the previous last call period were addressed is available at http://www.w3.org/MarkUp/2008/xhtml-role-lc-doc-20080216.html . This second Last Call period extends through 10 May 2008.

Publication as a Working Draft does not imply endorsement by the W3C Membership. This is a draft document and may be updated, replaced or obsoleted by other documents at any time. It is inappropriate to cite this document as other than work in progress.

Please report errors in this specification to [email protected] (archive). It is inappropriate to send discussion email to this address. Public discussion may take place on [email protected] (archive).

1. Introduction

This document is a module designed to be used to help extend the scope of XHTML-family markup languages into new environments. It has been developed in conjunction with the accessibility community and other groups to make it easier to describe the semantic meaning of XHTML-family document content.

2. Conformance Requirements

The keywords "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in [RFC2119].

Note that all examples in this document are informative, and are not meant to be interpreted as normative requirements.

2.1. Document Conformance

XHTML Role Attribute Module is not a stand-alone document type. It is intended to be integrated into other host languages such as XHTML. A conforming XHTML Role Attribute Module document is a document that requires only the facilities described as mandatory in this specification and the facilities described as mandatory in its host language. Such a document must meet all the following criteria:

2.2. Host Language Conformance

When the XHTML Role Attribute Module is included in a host language, all of the facilities required in this specification MUST be included in the host language. In addition, the attribute defined in this specification MUST be included in the content model of the host language.

3. The XHTML Role Attribute

The Role Attribute Module defines the role attribute and some values for that attribute in the default vocabulary space. The role attribute takes as its value one or more whitespace separated CURIEs [CURIE]. Any non-qualified value MUST be interpreted as being from the XHTML vocabulary at http://www.w3.org/1999/xhtml/vocab#. For a list of all roles in the default vocabulary, see [XHTMLVOCAB].

The attribute describes the role(s) the current element plays in the context of the document. This can be used, for example, by applications and assistive technologies to determine the purpose of an element. This could allow a user to make informed decisions on which actions may be taken on an element and activate the selected action in a device independent way. It could also be used as a mechanism for annotating portions of a document in a domain specific way (e.g., a legal term taxonomy).

This example is informative

<ul role="navigation sitemap">
    <li href="downloads">Downloads</li>
    <li href="docs">Documentation</li>
    <li href="news">News</li>
</ul>

The following list represents some of the roles defined in the default vocabulary. They are intended to define regions of the document to help orient the user.

3.1. Extending the collection of roles

It is possible to define additional role values. Such values MUST be defined in their own vocabulary. Note that current best practice is that the URI associated with that vocabulary resolve to a resource that allows for the discovery of the definition of the roles in the vocabulary. Example definitions include the RDF/OWL Taxonomy for the XHTML role attribute values in Appendix C, and the Web Accessibility Initiative's work on an RDF Taxonomy [ARIA-ROLE].

A. DTD Implementation

The DTD implementation of XHTML Role Attribute Module conforms to the requirements defined in [XHTMLMOD]. Consequently, it provides a Qualified Names declaration module.

A.1. Qualified Names Module

Note that this module defines the parameter entity %xhtml-role-attrs.qname;. This entity is intended to be used in the attribute lists of elements in any host language that permits the use of the role attribute on elements in its own namespace. If a host language does not permit role in its namespace, then the host language driver should set a parameter entity


%XHTML-ROLE.prefixed;

to INCLUDE and a parameter entity %XHTML-ROLE.prefix; to a value that is the prefix for the XHTML Role Attribute Module attribute.

B. Schema Implementation

The schema implementation of XHTML Role Attribute Module conforms to the requirements defined in [XHTMLMOD]. It is included here as an example implementation.

B.1. Attributes Module

C. RDF/OWL Taxonomy

The following example shows a way to define the collection of role attributes in the XHTML vocabulary space using RDF/OWL.

This example is informative

<?xml version="1.0"?>
<!DOCTYPE rdf:RDF [
    <!ENTITY xsd "http://www.w3.org/2001/XMLSchema#">
    <!ENTITY dc "http://dublincore.org/2003/03/24/dces#">
    <!ENTITY owl "http://www.w3.org/2002/07/owl#">
    <!ENTITY rdfs "http://www.w3.org/2000/01/rdf-schema#">
    <!ENTITY rdf "http://www.w3.org/1999/02/22-rdf-syntax-ns#">
    <!ENTITY states "http://www.w3.org/2005/07/aaa#">
    <!ENTITY wairole "http://www.w3.org/2005/01/wai-rdf/GUIRoleTaxonomy#">
]>
<rdf:RDF xml:base="http://www.w3.org/1999/xhtml" 
    xmlns:dc="http://purl.org/dc/elements/1.1/#" 
    xmlns:owl="http://www.w3.org/2002/07/owl#" 
    xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#" 
    xmlns:rdfs="http://www.w3.org/2000/01/rdf-schema#" 
    xmlns:states="http://www.w3.org/2005/07/aaa#" 
    xmlns:wairole="http://www.w3.org/2005/01/wai-rdf/GUIRoleTaxonomy#" >
    <owl:Class rdf:ID="banner">
        <rdfs:subClassOf rdf:resource="wairole:region"/>
        <wairole:scope rdf:resource="wairole:document"/>
        <dc:description xml:lang="en">
        A region that contains the prime heading or internal title of a
        page.
        </dc:description>
    </owl:Class>
    <owl:Class rdf:ID="complementary">
        <rdfs:subClassOf rdf:resource="wairole:region"/>
        <wairole:scope rdf:resource="wairole:document"/>
        <dc:description xml:lang="en">
        Any section of the document that supports but is separable 
        from the main content, but is semantically meaningful on its 
        own even when separated from it.
        </dc:description>
    </owl:Class>
    <owl:Class rdf:ID="contentinfo">
        <rdfs:subClassOf rdf:resource="wairole:region"/>
        <wairole:scope rdf:resource="wairole:document"/>
        <dc:description xml:lang="en">
        Meta information about the content on the page or the page as
        a whole.
        </dc:description>
    </owl:Class>
    <owl:Class rdf:ID="definition">
        <rdfs:subClassOf rdf:resource="wairole:section"/>
        <wairole:scope rdf:resource="wairole:document"/>
        <dc:description xml:lang="en">
        A definition of a term or concept.
        </dc:description>
    </owl:Class>
    <owl:Class rdf:ID="main">
        <rdfs:subClassOf rdf:resource="wairole:region"/>
        <wairole:scope rdf:resource="wairole:document"/>
        <dc:description xml:lang="en">
        This defines the main content of a document.
        </dc:description>
    </owl:Class>
    <owl:Class rdf:ID="navigation">
        <rdfs:subClassOf rdf:resource="wairole:region"/>
        <wairole:scope rdf:resource="wairole:document"/>
        <wairole:relatedConcept rdf:resource="wairole:menu"/>
        <dc:description xml:lang="en">
        A collection of links suitable for use when navigating the
        document or related documents.
        </dc:description>
    </owl:Class>
    <owl:Class rdf:ID="note">
        <rdfs:subClassOf rdf:resource="wairole:section"/>
        <wairole:scope rdf:resource="wairole:document"/>
        <dc:description xml:lang="en">
        The content is parenthetic or ancillary to the main content 
        of the resource.
        </dc:description>
    </owl:Class>
    <owl:Class rdf:ID="search">
        <rdfs:subClassOf rdf:resource="wairole:region"/>
        <wairole:scope rdf:resource="wairole:document"/>
        <dc:description xml:lang="en">
        The search tool of a web document.
        </dc:description>
    </owl:Class>
</rdf:RDF>

D. References

D.1. Normative References

D.2. Other References

E. Acknowledgments

At the time of publication, the participants in the W3C XHTML 2 Working Group were: