Audit aria-required-parent

Applicability

This rule applies to any HTML or SVG element that is included in the accessibility tree and has a WAI-ARIA 1.2 explicit semantic role with a required context role, except if the element has an implicit semantic role that is identical to its explicit semantic role.

Expectation

Each test target is the child in the accessibility tree of an element that has a semantic role that is one of the required context roles of the target element.

Background

The applicability of this rule is limited to the WAI-ARIA 1.2 Recommendation roles. The WAI-ARIA Graphics Module does not include any required context roles. The Digital Publishing WAI-ARIA Module (DPUB ARIA) 1.0 only has two roles with required context roles (doc-biblioentry and doc-endnote); both of them have issues with their use of role inheritance, and both of them are deprecated in the Digital Publishing WAI-ARIA Module (DPUB ARIA) 1.1 editor's draft.

An example of an element that has an implicit semantic role that is identical to its explicit semantic role is a <li role="listitem"> element. These elements are not applicable because they have extra requirements and should thus be checked separately.

Being a child in the accessibility tree is different from being a child in the DOM tree. Some DOM nodes have no corresponding node in the accessibility tree (for example, because they are marked with role="presentation"). A child in the accessibility tree can thus correspond to a descendant in the DOM tree. Additionally, the use of aria-owns attribute can change the tree structure to something which is not a subtree of the DOM tree.

This rule is restricted to direct parent-child relation in the accessibility tree which is more strict than the definition of "owned element" in WAI-ARIA. This rule mimics, on the roles level, the content model of HTML.

Subclass roles of required context roles are not automatically included as possible required context roles. For example, the feed role is not a possible required context role for listitem, even though feed is a subclass role of the list role.

Some user agents try to correct missing required context roles or incorrect content model. This often results, for example, in an isolated list item being presented as part of a one-item list containing only itself. Therefore, most test cases contain several targets to try and circumvent these corrections in order to better demonstrate the issue.

Assumptions

The rule assumes that the explicit role of the applicable elements is appropriate for their element. I.e. A heading incorrectly marked up with role="cell" does not fail success criterion 1.3.1 Info and Relationships for not being in the context of a row. Having an inappropriate role is itself an issue under 1.3.1 Info and Relationships, so in either scenario a failure of this rule means this success criterion is not satisfied.

Accessibility Support

• User agents do not all have the same accessibility tree. This can lead to different results for this rule, depending on which accessibility tree is used as input.
• aria-owns has limited support in some user agents.
• There exist some combination of popular browsers and assistive technologies who do not announce correctly relationships based on a mix of implicit and explicit roles.

Bibliography

• Understanding Success Criterion 1.3.1: Info and Relationships
• Required Context Role

Test Cases

Passed

Passed Example 1

These elements with an explicit role of listitem are children in the accessibility tree of an element with their required context role, list, expressed as an explicit role.

<div role="list">
	<div role="listitem">List item 1</div>
	<div role="listitem">List item 2</div>
</div>

Passed Example 2

These elements with an explicit role of listitem are children in the accessibility tree of an element with their required context role, list, expressed as an implicit role of ul. Note that this test case does not satisfy Success Criterion 4.1.1 Parsing because the ul element does not respect its content model.

<ul>
	<div role="listitem">List item 1</div>
	<div role="listitem">List item 2</div>
</ul>

Passed Example 3

These elements with an explicit role of listitem are children in the accessibility tree of an element with their required context role even though they are not its children in DOM. The presentational node is not included in the accessibility tree.

<div role="list">
	<div role="presentation">
		<div role="listitem">List item 1</div>
		<div role="listitem">List item 2</div>
	</div>
</div>

Passed Example 4

These elements with an explicit role of listitem are children in the accessibility tree of an element with their required context role even though they are not its DOM descendants. The aria-owns attribute is used to alter the accessibility tree and place the target elements in their required context role.

<div role="list" aria-owns="item1 item2"></div>
<div id="item1" role="listitem">List item 1</div>
<div id="item2" role="listitem">List item 2</div>

Passed Example 5

These elements with an explicit role of listitem are children in the accessibility tree of an element with their required context role even though they are not its DOM children. The aria-owns attribute is used to alter the accessibility tree and place the target elements in their required context role.

<div role="list" aria-owns="item1 item2">
	<div role="listitem">
		<div id="item1" role="listitem">List item 1</div>
		<div id="item2" role="listitem">List item 2</div>
	</div>
</div>

Passed Example 6

These elements with an explicit role of listitem are children in the accessibility tree of an element with their required context role because the accessibility tree mimics the DOM tree across shadow boundaries.

<div id="host" role="list"></div>

<script>
	const host = document.querySelector('#host')
	const root = host.attachShadow({ mode: 'open' })
	root.innerHTML = '<div role="listitem">List item 1</div> <div role="listitem">List item 2</div>'
</script>

Failed

Failed Example 1

This element with an explicit role of listitem is not a child in the accessibility tree of an element with its required context role.

<div role="listitem">List item 1</div>

Failed Example 2

These elements with an explicit role of listitem are not children in the accessibility tree of an element with their required context role, but of an element with the tabpanel role.

<div role="list">
	<div role="tabpanel">
		<div role="listitem">List item 1</div>
		<div role="listitem">List item 2</div>
	</div>
</div>

Failed Example 3

These elements with an explicit role of listitem are not children in the accessibility tree of an element with their required context role. They are instead children in the accessibility tree of the div with an aria-live attribute; even though this div has no role, it has a global ARIA attribute and is thus included in the accessibility tree.

<div role="list">
	<div aria-live="polite">
		<div role="listitem">List item 1</div>
		<div role="listitem">List item 2</div>
	</div>
</div>

Failed Example 4

These elements with an explicit role of listitem are not children in the accessibility tree of an element with their required context role because explicit parent-child relation in the accessibility tree (set by aria-owns) does not cross shadow boundaries.

<div role="list" aria-owns="item1 item2"></div>

<div id="host"></div>

<script>
	const host = document.querySelector('#host')
	const root = host.attachShadow({ mode: 'open' })
	root.innerHTML = '<div id="item1" role="listitem">List item 1</div> <div id="item2" role="listitem">List item 2</div>'
</script>

Inapplicable

Inapplicable Example 1

This element with an explicit role of listitem is not included in the accessibility tree.

<div role="listitem" style="display:none;">List item 1</div>

Inapplicable Example 2

There is no element with an explicit role.

<ul>
	<li>List item 1</li>
</ul>

Inapplicable Example 3

This section element with an explicit role of doc-abstract has a role from the Digital Publishing WAI-ARIA Module (DPUB ARIA) 1.0, not the WAI-ARIA 1.2 Recommendation.

<section role="doc-abstract" aria-label="Abstract">
	<p>Accessibility of web content requires semantic information about widgets, structures, and behaviors …</p>
</section>

Inapplicable Example 4

There is no element whose role has required context role because the heading role does not have one.

<div role="heading" aria-level="1">Hello!</div>
<p>Welcome to my homepage!</p>

Inapplicable Example 5

There is no element with an explicit role different from its implicit role. This li element has an explicit role of listitem which is identical to its implicit role.

<ul>
	<li role="listitem">List item 1</li>
</ul>