aria-details

The aria-details attribute can be used to provide additional information or complex descriptions to an object. It is used to inform assistive technology users about the content by providing more in-depth information, whether that content is within the current document or a link to additional assets.

There are other HTML and WAI-ARIA properties that have similar purposes. The HTML <label> element and the aria-label and aria-labelledby properties are used to provide short labels for an object. The HTML title attribute and the aria-description and aria-describedby properties provide for longer plain text descriptions of an object. However, when additional information, complex descriptions, or navigable content related to the object is necessary and available, the aria-details attribute should be used.

The aria-details attribute serves a similar purpose as HTML's never fully-supported longdesc attribute － a URL of a long description to a replaced element's content － which was deprecated due to lack of support and misuse.

The aria-details attribute takes the id, or space separated list of ids of the elements to get more detailed information as its values. When aria-details is included on an element, assistive technologies inform users of the availability of extended information, enabling the user to navigate to the referenced content.

Elements referenced by aria-details are intended to contain more information than would normally be provided via aria-describedby.

The elements referenced by aria-details should be visible to all users. aria-details informs users that otherwise might not be able to scan a screen and discern quickly that the explanatory content is available.

Unlike aria-describedby, elements referenced by aria-details are not used in accessible descriptions and are not turned into a plain string when presented to assistive technology users. If the associated content is not too long and flattening the contents of the referenced element to a simple string of text wouldn't cause loss of information, consider using aria-describedby instead. That said, it is valid for an element to have both aria-details and a description specified with either aria-describedby or aria-description.

When it comes to definition and term roles, the aria-details would be included on the term element with the id of the element with a definition role.

<p>The <strong>cubic-bezier()<strong> functional notation defines a cubic
  <span role="term" aria-details="bezier bezImg">Bézier curve</span>. As
  these curves are continuous, they are often used to smooth down the start and
  end of the curve and are therefore sometimes called easing functions.
</p>

<p role="definition" id="bezier">A <strong>Bézier curve</strong>,
 (Pronounced \ ˈbe-zē-ˌā \)
 <i aria-description="English pronunciation">BEH-zee-ay</i>) is a mathematically
 described curve used in computer graphics and animation. The curve is defined
 by a set of control points with a minimum of two. Web related graphics
 and animations use Cubic Béziers, which are curves with four control
 points P<sub>0</sub>, P<sub>1</sub>, P<sub>2</sub>, and P<sub>3</sub>.
</p>

<a href="bezierExplanation.html" id="bezImg"
  aria-label="Explanation of Bézier curve in CSS timing functions">
  <img alt="Animated Bézier curve showing 4 control points." src="bezier.gif">
</a>

ID reference list

An id or space separated list of ids of elements that provide or link to additional related information.

Used in ALL roles.

• HTML id attribute
• aria-labelledby
• aria-describedby
• aria-description
• The image alt attribute
• HTML title attribute