Unexplained computation in glossary/accessible-name

[PassionPenguin]

MDN URL

https://developer.mozilla.org/en-US/docs/Glossary/Accessible_description

What specific section or headline is this issue about?

NA

What information was incorrect, unhelpful, or incomplete?

The computation of the section cannot be found in WAI:

The accessible description for a [<table>](https://developer.mozilla.org/en-US/docs/Web/HTML/Element/table) is its first [<caption>](https://developer.mozilla.org/en-US/docs/Web/HTML/Element/caption), for the [<figure>](https://developer.mozilla.org/en-US/docs/Web/HTML/Element/figure), is the [<figcaption>](https://developer.mozilla.org/en-US/docs/Web/HTML/Element/figcaption), for the [<summary>](https://developer.mozilla.org/en-US/docs/Web/HTML/Element/summary), is the content of the [<details>](https://developer.mozilla.org/en-US/docs/Web/HTML/Element/details) it is nested in, and for the button [<input>](https://developer.mozilla.org/en-US/docs/Web/HTML/Element/input) elements, it is the value attribute's value, unless the element also has a aria-describedby or aria-description attribute, which takes precedence.

For other elements, the description needs to be programmatically associated with the related element. In these cases, the accessible description is provided by the [aria-describedby](https://developer.mozilla.org/en-US/docs/Web/Accessibility/ARIA/Attributes/aria-describedby) attribute, [aria-description](https://developer.mozilla.org/en-US/docs/Web/Accessibility/ARIA/Attributes/aria-description) attribute, or the [title](https://developer.mozilla.org/en-US/docs/Web/HTML/Global_attributes#title) attribute, if the title would not otherwise also be the [accessible name](https://developer.mozilla.org/en-US/docs/Glossary/Accessible_name) for that element, in that order of precedence.

As for WAI-ARIA, the current spec for accessible description computation, I can only know that the the computation is:

If [aria-describedby](https://www.w3.org/TR/2014/REC-wai-aria-20140320/states_and_properties#aria-describedby) is present, [user agents](https://www.w3.org/TR/2014/REC-wai-aria-implementation-20140320/#def_useragent) MUST compute the accessible description by concatenating the text alternatives for nodes referenced by an aria-describedby attribute on the current node. The text alternatives for the referenced nodes are computed using a number of methods, outlined below in the section titled [Text Alternative Computation](https://www.w3.org/TR/2014/REC-wai-aria-implementation-20140320/#mapping_additional_nd_te).

The computation by aria-description, host language feature are not found in that spec. It seems that the author did mixed with HTML-AAM which is still in draft.

If the content is about a spec in draft, then it still have problem that <figure> computation does not match that draft.

What did you expect to see?

If aria-describedby is present, user agents MUST compute the accessible description by concatenating the text alternatives for nodes referenced by an aria-describedby attribute on the current node. The text alternatives for the referenced nodes are computed using a number of methods, outlined below in the section titled Text Alternative Computation.

Do you have any supporting links, references, or citations?

Spec

WAI-ARIA 5.6.1.2

Draft

• Accessible Name Description Computation
• HTML-AAM Accessible Description Computation
• SVG-AAM Accessible Description Computation

Do you have anything more you want to share?

No response

[PassionPenguin]

I was just doing some translation and editing, as just when I write the stuff below, I found that these precedence and orders are still in DRAFT. The attribute aria-description even not appeared in the WAI-ARIA page.

Accessible Description Computation

HTML

For HTML elements, the description needs to be programmatically associated with the related element. The order is as follows:

1. aria-describedby attribute;
2. aria-description attribute;
3. by host language features which participate in the description calculation, if it would not otherwise also be the {{glossary("accessible name")}} for that element. Host language features are defined in HTML-AAM, SVG-AAM, or other host language documentation for more information on markup that defines a text alternative.
4. title attribute, if it would not otherwise also be the {{glossary("accessible name")}} for that element.

For the host language features in HTML that participate in the description calculation, they are (as defined in HTML-AAM):

1. {htmlelement("table")}}: its first {{htmlelement("caption")}}.
2. {{htmlelement("summary")}}: the content of {{htmlelement("details")}} it is nested in.
3. {{htmlelement("input")}} buttons(with type attribute button, submit or reset): the value attribute's value.

SVG

For SVG elements, the description needs to be programmatically associated with the related element. The order is as follows (as defined in SVG-AAM):

1. aria-describedby attribute;
2. a direct child desc element
3. for text container elements, the text content
4. a direct child title element that provides a tooltip, when ARIA label attributes are used to provide the accessible name
5. xlink:title attribute on a link, if not used to provide the accessible name

Descriptions are reduced to text strings. For example, if an element's aria-describedby attribute value is the id of an HTML {{htmlelement("img")}}, the description is the description of the image (usually the image's alt attribute).

You can inspect the accessible description for any element on your page: look at your browser's developer tools' accessibility tab, which provides the accessibility information for the currently selected element.

See also

• {{glossary("accessible name")}} glossary term
• ARIA roles
• ARIA attribute
• Accessibility
• Learn accessibility
• Accessible Name Description Computation
• HTML-AAM Accessible Description Computation
• SVG-AAM Accessible Description Computation