role attribute has valid value

Rule Type:
atomic
Rule ID:
674b10
Last Modified:
June 3, 2021
Accessibility Requirements Mapping:
1.3.1 Info and Relationships (Level A)
  • Required for conformance to WCAG 2.0 and later on level A and higher
  • Outcome mapping:
    • Any failed outcomes: success criterion is not satisfied
    • All passed outcomes: success criterion needs further testing
    • An inapplicable outcome: success criterion needs further testing
ARIA4: Using a WAI-ARIA role to expose the role of a user interface component
  • Not required to conformance to any W3C accessibility recommendation.
  • Outcome mapping:
    • Any failed outcomes: technique is not satisfied
    • All passed outcomes: technique needs further testing
    • An inapplicable outcome: technique needs further testing
G108: Using markup features to expose the name and role, allow user-settable properties to be directly set, and provide notification of changes
  • Not required to conformance to any W3C accessibility recommendation.
  • Outcome mapping:
    • Any failed outcomes: technique is not satisfied
    • All passed outcomes: technique needs further testing
    • An inapplicable outcome: technique needs further testing
Input Aspects:
DOM Tree
CSS Styling

Description

This rule checks that each role attribute has a valid value.

Applicability

This rule applies to any role attribute for which all the following are true:

Expectation

Each test target has at least one token which is a valid value corresponding to a non-abstract role from WAI-ARIA Specifications.

Assumptions

Accessibility Support

Older browsers do not support more than one token in the value for a role attribute. If multiple values are used in the role attribute, the attribute is ignored in these browsers.

Background

The role attribute is a set of space separated tokens. Having a whitespace separated list of more than one token in the value of the role attribute is used for what is known as fallback roles. If the first token is not accessibility supported (or valid), the next one will be used for determining the semantic role of the element, and so forth. Having the rule target attributes containing at least one non-ASCII whitespace character ensures that there is at least one token in the set.

Test Cases

Passed

Passed Example 1

This role attribute contains one token, and this token is a valid WAI-ARIA role.

<label>Search: <input type="text" role="searchbox" placeholder="Enter 3 or more characters"/></label>

Passed Example 2

This role attribute contains two tokens, and these tokens are both valid WAI-ARIA roles.

<style>
	.ref {
		color: #0000ee;
		text-decoration: underline;
		cursor: pointer;
	}
</style>
See [<span class="ref" onclick="location.href='https://act-rules.github.io/'" role="doc-biblioref link">ACT rules</span
>].

Passed Example 3

This role attribute contains two tokens, and one of these tokens (searchbox) is a valid WAI-ARIA role.

<label>Search: <input type="text" role="searchfield searchbox" placeholder="Enter 3 or more characters"/></label>

Failed

Failed Example 1

This role attribute contains one token, but this token is not a valid role in any of the WAI-ARIA specifications.

<style>
	.link {
		color: #0000ee;
		text-decoration: underline;
		cursor: pointer;
	}
</style>
I love <span class="link" onclick="location.href='https://act-rules.github.io/'" role="lnik">ACT rules</span>.

Failed Example 2

This role attribute contains two tokens, but none of these tokens is a valid role in any of the WAI-ARIA specifications.

<style>
	.ref {
		color: #0000ee;
		text-decoration: underline;
		cursor: pointer;
	}
</style>
See [<span class="ref" onclick="location.href='https://act-rules.github.io/'" role="bibliographic-reference lnik"
	>ACT rules</span
>].

Inapplicable

Inapplicable Example 1

There is no role attribute.

<img src="/test-assets/shared/w3c-logo.png" alt="W3C logo" />

Inapplicable Example 2

This role attribute has no value.

<div role>Some Content</div>

Inapplicable Example 3

This role attribute is empty (“”).

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

Inapplicable Example 4

This role attribute is only ASCII whitespace.

<input type="text" role=" " />

Inapplicable Example 5

This role attribute is specified on an element which is not included in the accessibility tree.

<div aria-hidden="true" role="banner">Some Content</div>

Glossary

Explicit Semantic Role

The explicit semantic role of an element is determined by its role attribute (if any).

The role attribute takes a list of tokens. The explicit semantic role is the first valid role in this list. The valid roles are all non-abstract roles from WAI-ARIA Specifications. If the element has no role attribute, or if it has one with no valid role, then this element has no explicit semantic role.

Other roles may be added as they become available. Not all roles will be supported in all assistive technologies. Testers are encouraged to adjust which roles are allowed according to the accessibility support base line. For the purposes of executing test cases in all rules, it should be assumed that all roles are supported by assistive technologies so that none of the roles fail due to lack of accessibility support.

Focusable

Elements that can become the target of keyboard input as described in the HTML specification of focusable and can be focused.

Hidden State

An HTML element’s hidden state is “true” if at least one of the following is true for itself or any of its ancestors in the flat tree:

In any other case, the element’s hidden state is “false”.

Implicit Semantic Role

The implicit semantic role of an element is a pre-defined value given by the host language which depends on the element and its ancestors.

Implicit roles for HTML and SVG, are documented in the HTML accessibility API mappings (working draft) and the SVG accessibility API mappings (working draft).

Included in the accessibility tree

Elements included in the accessibility tree of platform specific accessibility APIs. Elements in the accessibility tree are exposed to assistive technologies, allowing users to interact with the elements in a way that meet the requirements of the individual user.

The general rules for when elements are included in the accessibility tree are defined in the core accessibility API mappings. For native markup languages, such as HTML and SVG, additional rules for when elements are included in the accessibility tree can be found in the HTML accessibility API mappings (working draft) and the SVG accessibility API mappings (working draft).

For more details, see examples of included in the accessibility tree.

Note: Users of assistive technologies might still be able to interact with elements that are not included in the accessibility tree. An example of this is a focusable element with an aria-hidden attribute with a value of true. Such an element could still be interacted using sequential keyboard navigation regardless of the assistive technologies used, even though the element would not be included in the accessibility tree.

Marked as decorative

An element is marked as decorative if one of the following conditions is true:

Elements are marked as decorative as a way to convey the intention of the author that they are pure decoration. It is different from the element actually being pure decoration as authors may make mistakes. It is different from the element being effectively ignored by assistive technologies as rules such as presentational roles conflict resolution may overwrite this intention.

Elements can also be ignored by assistive technologies if their hidden state is true. This is different from marking the element as decorative and does not convey the same intention. Notably, the hidden state of an element may change as users interact with the page (showing and hiding elements) while being marked as decorative should stay the same through all states of the page.

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.

Semantic Role

The semantic role of an element is determined by the first of these cases that applies:

  1. Conflict If the element is marked as decorative, but the element is included in the accessibility tree; or would be included in the accessibility tree when its hidden state is false, then its semantic role is its implicit role.
  2. Explicit If the element has an explicit role, then its semantic role is its explicit role.
  3. Implicit The semantic role of the element is its implicit role.

WAI-ARIA specifications

The WAI ARIA Specifications group both the WAI ARIA W3C Recommendation and ARIA modules, namely:

Note: depending on the type of content being evaluated, part of the specifications might be irrelevant and should be ignored.

Whitespace

Whitespace are characters that have the Unicode “White_Space” property in the Unicode properties list.

This includes:

Acknowledgements

This rule was written in the ACT Rules community group, with the support of the EU-funded WAI-Tools Project.

Authors

Changelog

This is the first version of this ACT rule.

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