W3C

WAI-ARIA 1.1 - aria-describedat

Unofficial Draft 21 March 2012

Editors:
Steve Faulkner, The Paciello Group sfaulkner@paciellogroup.com
Richard Schwerdtfeger, IBM schwer@us.ibm.com

aria-describedat (property)

Specifies a hyperlink [HTML5] to content that describes the object. The attribute value MUST be a valid non-empty URL potentially surrounded by spaces [HTML5] which references a separate document or a content fragment in a separate document or a content fragment within the same document as the object.

Examples:

aria-descibedat linking to a seperate document:

<img src="shalott.jpg" alt="A painting inspired by Alfred Tennyson's poem The Lady of Shalott" aria-describedat="http://example.com">

aria-descibedat linking to a content fragment in a separate document:

<img src="shalott.jpg" alt="A painting inspired by Alfred Tennyson's poem The Lady of Shalott" aria-describedat="http://example.com#description">

aria-descibedat linking to a content fragment within the same document:

<canvas aria-describedat="#canvas-desc">
<div id="canvas-desc"><h2>Shapes</h2>
<p>A rectangle with a black border. In the background is a pink circle. Partially overlaying the
<a href="http://en.wikipedia.org/wiki/Circle">circle</a>. Partially overlaying the circle is a green
<a href="http://en.wikipedia.org/wiki/Square">square</a>
and a purple <a href="http://en.wikipedia.org/wiki/Triangle">triangle</a>,
both of which are semi-opaque, so the full circle can be seen underneath.</p></div>
</canvas>

If the element containing the aria-describedat attribute is visible the user agent SHOULD render an indication to the user, in context of the element containing the aria-describedat attribute, that additional information may be referenced. User agents SHOULD provide a device independent mechanism to allow a user to direct their user agent to render the content referenced by the aria-describedat attribute.  The user agent SHOULD provide a device independent mechanism to close the rendered content and return the user's point of regard to that the user was at prior to rendering the content refrenced by aria-describedat.

For example, a user agent MAY provide access to the document or document fragment referenced by the the aria-describedat attribute in a context menu associated with the object. In this case the context menu SHOULD be operable using the keyboard and a visible indication of aria-describedat presence SHOULD be provided. The object itself SHOULD be included in the default tab order to provide input device independent access to the associated context menu. The option to disable visible indication and access MAY be provided via a user preference.

Characteristics of aria-describedat
CharacteristicValue
Used in Roles:All elements of the base markup

 

Values of aria-describedat
value Description
undefined (default): The element does not have a description associated using aria-describedat.
URL valid non-empty URL potentially surrounded by spaces [HTML5]