Skip to content

Proposed ARIA state or property has valid value

Description

This rule checks that each ARIA state or property has a valid value type.

Applicability

This rule applies to any WAI-ARIA state or property that has a non-empty (“”) [attribute value][], and that is specified on an HTML or SVG element.

Expectation

Each test target has an [attribute value][] that is valid according to its WAI-ARIA value type.

Exception: For value types ID Reference and ID Reference List no ID referenced elements are required.

Assumptions

There are no assumptions.

Accessibility Support

Some user agents treat the value of aria-* attribute as case-sensitive (even when these are not ID) while some treat them as case-insensitive.

Background

Using invalid ARIA attribute values is often the result of a typo or other developer error. These attributes are then either ignored, or a default value is assumed by browsers and assistive technologies. This often means that a state or property which should exist is missing or has an unexpected value. This can cause issues under success criterion 1.3.1 Info and Relationships or 4.1.2 Name, Rule Value. If the default value for invalid attribute values happens to match the author’s intention for the value, there will not be an accessibility issue.

This rule does not require the target of an ID Reference to exist. This is because referencing an element that does not exist, and not having the reference at all has the same end result. A common use case for using ID Reference for a non-existing ID is to use a static aria-errormessage on an input element, and to only insert the element with the error message if there is an actual error. There are some cases in which ID references are required. These are tested in a separate rule.

Bibliography

Accessibility Requirements Mapping

Input Aspects

The following aspects are required in using this rule.

Test Cases

Passed

Passed Example 1

Open in a new tab

The aria-label [attribute value][] of Family name is allowed for the string value type.

<div role="textbox" aria-label="Family name"></div>

Passed Example 2

Open in a new tab

The aria-required [attribute value][] of true is allowed for the true/false value type.

<div role="textbox" aria-required="true" aria-label="Family name"></div>

Passed Example 3

Open in a new tab

The aria-expanded [attribute value][] of undefined is allowed for the true/false/undefined value type.

<div role="button" aria-expanded="undefined">A button</div>

Passed Example 4

Open in a new tab

The aria-pressed [attribute value][] of mixed is allowed for the tristate value type.

<div role="button" aria-pressed="mixed">Partially pressed button</div>

Passed Example 5

Open in a new tab

The aria-errormessage [attribute value][] is an ID Reference value type. The presence of an element with a matching ID is not required by this rule.

<div role="textbox" aria-errormessage="my-error" aria-label="A textbox"></div>

Passed Example 6

Open in a new tab

The aria-owns [attribute value][] is a valid ID Reference List value type. Both tokens reference elements that exist in the same [DOM tree][].

<h1>Shopping list</h1>
<div role="list" aria-owns="item1 item2"></div>
<div id="item1">Apples</div>
<div id="item2">Bananas</div>

Passed Example 7

Open in a new tab

The aria-rowindex [attribute value][] of 2 is a valid integer value type.

<div role="gridcell" aria-rowindex="2">Fred</div>

Passed Example 8

Open in a new tab

The aria-valuemin, aria-valuemax and aria-valuenow [attribute values][attribute value] are valid for a number value type.

<div role="spinbutton" aria-valuemin="1.0" aria-valuemax="2.0" aria-valuenow="1.5" aria-label="Select a value"></div>

Passed Example 9

Open in a new tab

The aria-current [attribute value][] of page is a valid token value type.

<a href="/" aria-current="page">Home</a>

Passed Example 10

Open in a new tab

The aria-relevant [attribute value][] has a text and removals tokens. Both are valid tokens for a aria-relevant token list value type.

<div role="alert" aria-relevant="text removals"></div>

Failed

Failed Example 1

Open in a new tab

The aria-required [attribute value][] of undefined is not valid for a true/false value type.

<div role="textbox" aria-required="undefined" aria-label="A required textbox"></div>

Failed Example 2

Open in a new tab

The aria-expanded [attribute value][] of collapsed is not valid for a true/false/undefined value type.

<div role="button" aria-expanded="collapsed">A button</div>

Failed Example 3

Open in a new tab

The aria-pressed [attribute value][] of horizontal is not valid for a tristate value type.

<div role="button" aria-pressed="horizontal">An other button</div>

Failed Example 4

Open in a new tab

The aria-rowindex [attribute value][] of 2.5 is not valid for an integer value type because it is a decimal number.

<div role="gridcell" aria-rowindex="2.5">Fred</div>

Failed Example 5

Open in a new tab

The aria-valuemin, aria-valuemax and aria-valuenow [attribute values][attribute value] are strings. These should all be of the number value type instead.

<div role="spinbutton" aria-valuemin="one" aria-valuemax="three" aria-valuenow="two" aria-label="Choose a value"></div>

Failed Example 6

Open in a new tab

The aria-live [attribute value][] of page is not a valid token, because page is not a token for aria-live.

<div role="main" aria-live="page"></div>

Failed Example 7

Open in a new tab

The aria-relevant [attribute value][] has the two tokens text and always. The always token is not valid for the aria-relevant token list. In order to be a valid value, all tokens must be valid.

<div role="alert" aria-relevant="text always"></div>

Inapplicable

Inapplicable Example 1

Open in a new tab

Element does not have any ARIA states or properties

<div>Some Content</div>

Inapplicable Example 2

Open in a new tab

Element has ARIA role, but no ARIA states or properties

<div role="button">Some Content</div>

Inapplicable Example 3

Open in a new tab

The aria-live attribute does not have a value.

<div role="alert" aria-live>Remember to be awesome!</div>

Inapplicable Example 4

Open in a new tab

The aria-hidden attribute is not on an HTML or SVG element.

<math aria-hidden="false"></math>

Glossary

Namespaced Element

An element with a specific namespaceURI value from HTML namespaces. For example an “SVG element” is any element with the “SVG namespace”, which is http://www.w3.org/2000/svg.

Namespaced elements are not limited to elements described in a specification. They also include custom elements. Elements such as a and title have a different namespace depending on where they are used. For example a title in an HTML page usually has the HTML namespace. When used in an svg element, a title element has the SVG namespace instead.

Outcome

An outcome is a conclusion that comes from evaluating an ACT Rule on a test subject or one of its constituent test target. An outcome can be one of the three following types:

Note: A rule has one passed or failed outcome for every test target. When there are no test targets the rule has one inapplicable outcome. This means that each test subject will have one or more outcomes.

Note: Implementations using the EARL10-Schema can express the outcome with the outcome property. In addition to passed, failed and inapplicable, EARL 1.0 also defined an incomplete outcome. While this cannot be the outcome of an ACT Rule when applied in its entirety, it often happens that rules are only partially evaluated. For example, when applicability was automated, but the expectations have to be evaluated manually. Such “interim” results can be expressed with the incomplete outcome.

Rule Versions

This is the first version of this ACT rule.

Implementations

This section is not part of the official rule. It is populated dynamically and not accounted for in the change history or the last modified date.

Implementation Type Consistency Report
Alfa (fully automated) 0.57.2 Automated tool Consistent Alfa (fully automated) Report
Alfa (semi-automated) 0.57.2 Semi-automated tool Consistent Alfa (semi-automated) Report
Axe DevTools Pro 4.37.1 Semi-automated tool Consistent Axe DevTools Pro Report
Axe-core 4.6.0 Automated tool Consistent Axe-core Report
Equal Access Accessibility Checker 3.1.42-rc.0 Automated tool Partial Equal Access Accessibility Checker Report
QualWeb 3.0.0 Automated tool Partial QualWeb Report
SortSite 6.45 Automated tool Partial SortSite Report
Total Validator 17.1.0 Linter Consistent Total Validator Report
Total Validator (+Browser) 17.1.0 Automated tool Consistent Total Validator (+Browser) Report
ember-template-lint 5.5.1 Linter Partial ember-template-lint Report
Back to Top

This is an unpublished draft preview that might include content that is not yet approved. The published website is at w3.org/WAI/.