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Proposed Test Rule: Visible label is part of accessible name

Description

This rule checks that interactive elements labeled through content have their visible label as part of their accessible name.

Applicability

This rule applies to any element for which all the following is true:

Expectation

For each target element, all text nodes in the visible text content either match or are contained within the accessible name of this target element, except for characters in the text nodes used to express non-text content. Leading and trailing whitespace and difference in case sensitivity should be ignored.

Assumptions

This rule assumes that all resources needed for rendering the page are properly loaded. Checking if resources are missing is out of the scope of rules. Missing resources may be rendered as text (for example, missing img are rendered as their alt attribute).

Accessibility Support

Implementation of Presentational Roles Conflict Resolution varies from one browser or assistive technology to another. Depending on this, some elements can have one of the applicable semantic roles and fail this rule with some technology but users of other technologies would not experience any accessibility issue.

Background

This rule applies to elements with a widget role that support name from content. This includes the following: button, checkbox, gridcell, link, menuitem, menuitemcheckbox, menuitemradio, option, radio, searchbox, switch, tab, treeitem.

The understanding document of 2.5.3 Label in Name use the term “symbolic text characters” to refer to a type of non-text content that uses text characters as symbols, such as using “x” to mean “close”. This rule considers them as “characters expressing non-text content”. Unicode emojis are another example of characters expressing non-text content, although these are not “symbolic text characters”.

Bibliography

Accessibility Requirements Mapping

Input Aspects

The following aspects are required in using this rule.

Test Cases

Passed

Passed Example 1

This link has visible text that matches the accessible name.

<a href="https://act-rules.github.io/" aria-label="ACT rules">ACT rules</a>

Passed Example 2

This link has visible text that, ignoring trailing whitespace, matches the accessible name.

<a href="https://act-rules.github.io/" aria-label="  ACT rules  ">ACT rules</a>

Passed Example 3

This link has visible text that, ignoring case, matches the accessible name.

<a href="https://act-rules.github.io/" aria-label="act rules">ACT rules</a>

Passed Example 4

This button has visible text that is contained within the accessible name.

<button aria-label="Next Page in the list">Next Page</button>

Passed Example 5

This button has visible text that does not need to be contained within the accessible name, because the “x” text node is non-text content.

<button aria-label="close">X</button>

Passed Example 6

This button element has the text “search” rendered as an magnifying glass icon by the font. Because the text is rendered as non-text content, the text does not need to be contained within the accessible name.

<link href="https://fonts.googleapis.com/icon?family=Material+Icons" rel="stylesheet" />
<style>
	button {
		font-family: 'Material Icons';
	}
</style>
<button aria-label="Find">search</button>

Failed

Failed Example 1

This link has visible text that is different from the accessible name.

<a href="https://act-rules.github.io/" aria-label="WCAG">ACT rules</a>

Failed Example 2

This button has visible text that is only partially contained within the accessible name.

<button aria-label="the full">The full label</button>

Failed Example 3

This link has visible text with mathematical symbols, that does not match the accessible name because the mathematical symbols were written out in the accessible name. This is explicitly mentioned in WCAG.

<a href="/" aria-label="Proof of two multiplied by two is four">Proof of 2&times;2=4</a>

Inapplicable

Inapplicable Example 1

This nav is not a widget, so the visible text does not need to match the accessible name.

<nav aria-label="main nav">W3C navigation</nav>

Inapplicable Example 2

This email text field does not need to have its visible text match the accessible name. The content of a textfield shows its value instead of its label; it does not support name from content. The label is usually adjacent to the textfield instead.

<div>E-mail</div>
<input type="email" aria-label="E-mail" value="Contact" />

Inapplicable Example 3

This div element does not have a widget role, so the visible text does not need to match the accessible name.

<div role="tooltip" aria-label="OK">Next</div>

Inapplicable Example 4

This link has no visible text content.

<a href="https://w3.org" aria-label="W3C homepage">
	<img src="/test-assets/shared/w3c-logo.png" alt="w3c logo" />
</a>

Glossary

Accessible Name

The accessible name is the programmatically determined name of a user interface element that is included in the accessibility tree.

The accessible name is calculated using the accessible name and description computation.

For native markup languages, such as HTML and SVG, additional information on how to calculate the accessible name can be found in HTML Accessibility API Mappings 1.0, Accessible Name and Description Computation (working draft) and SVG Accessibility API Mappings, Name and Description (working draft).

For more details, see examples of accessible name.

Note: As per the accessible name and description computation, each element always has an accessible name. When no accessible name is provided, the element will nonetheless be assigned an empty ("") one.

Note: As per the accessible name and description computation, accessible names are flat string trimmed of leading and trailing whitespace. Notably, it is not possible for a non-empty accessible name to be composed only of whitespace since these must be trimmed.

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.

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 are exposed to assistive technologies. This allows users of assistive technology to access the elements in a way that meets 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.

Programmatically hidden elements are removed from the accessibility tree. However, some browsers will leave focusable elements with an aria-hidden attribute set to true in the accessibility tree. Because they are hidden, these elements are considered not included in the accessibility tree. This may cause confusion for users of assistive technologies because they may still be able to interact with these focusable elements using sequential keyboard navigation, even though the element should not be included in the accessibility tree.

Marked as decorative

An element is marked as decorative if one or more 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 they are programmatically hidden. This is different from marking the element as decorative and does not convey the same intention. Notably, being programmatically hidden 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.

Programmatically Hidden

An HTML element is programmatically hidden if either it has a computed CSS property visibility whose value is not visible; or at least one of the following is true for any of its inclusive ancestors in the flat tree:

Note: Contrarily to the other conditions, the visibility CSS property may be reverted by descendants.

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 it is not programmatically hidden, 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.

This definition can be used in expressions such as “semantic button” meaning any element with a semantic role of button.

Visible

Content perceivable through sight.

Content is considered visible if making it fully transparent would result in a difference in the pixels rendered for any part of the document that is currently within the viewport or can be brought into the viewport via scrolling.

Content is defined in WCAG.

For more details, see examples of visible.

Visible Text Content

The visible text content of an element is a set of all visible text nodes that are descendants in the flat tree of this element

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:

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 Consistency Complete Report
Axe-core Consistent Yes View Report
QualWeb Consistent Yes View Report
SortSite Consistent Yes View Report

Changelog

This is the first version of this ACT rule.

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