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Proposed Link in context is descriptive

Description

This rule checks that the accessible name of a link together with its context describes its purpose.

Applicability

This rule applies to any inheriting semantic link for which all the following is true:

Expectation

The accessible name of each target element together with its programmatically determined link context describes the purpose of the link.

Assumptions

Accessibility Support

Background

This rule is designed specifically for 2.4.4 Link Purpose (In Context), which requires the purpose to be clear within the context of a link. Because links that do not have this, also are not clear without that context, this rule maps to 2.4.9 Link Purpose (Link only) as well. In order to adequately test the expectation, some of the passed examples do not satisfy 2.4.9 Link Purpose (Link only).

Bibliography

Accessibility Requirements Mapping

Input Aspects

The following aspects are required in using this rule.

Test Cases

Passed

Passed Example 1

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The accessible name (from the link’s text) describes the purpose of the link.

<a href="#desc">See the description of this product.</a>

<p id="desc">This product consists of several web pages.</p>

Passed Example 2

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The accessible name describes the purpose of the link.

<a href="#main"><img src="/test-assets/5effbb/main.png" alt="Go to the main content"/></a>

<main>
	<p id="main">This is the main content.</p>
</main>

Passed Example 3

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The accessible name (from the link’s text), together with its programmatically determined link context (available from the text in the closest p ancestor), describes the purpose of the link.

<p>See the description of <a href="#desc">this product</a>.</p>

<p id="desc">This product consists of several web pages.</p>

Passed Example 4

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The accessible name (from the link’s text) describes the purpose of the link.

<span role="link" tabindex="0" onclick="document.location+='#desc'">See description of the product.</span>

<p id="desc">This product consists of several web pages.</p>

Passed Example 5

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The programmatically determined link context (provided by the ancestor with a role of listitem and text “Ulysses”) and the accessible name (from the link’s text) describe the purpose of the links.

<ul>
	<li>
		Ulysses
		<ul>
			<li><a href="https://www.gutenberg.org/files/4300/4300-h/4300-h.htm"> HTML </a></li>
			<li>
				<a href="https://www.gutenberg.org/ebooks/4300.epub.images?session_id=04cd710372888de8d8d322215cdfe8ce5b0f8d73">
					EPUB
				</a>
			</li>
			<li><a href="https://www.gutenberg.org/files/4300/4300-0.txt"> Plain text </a></li>
		</ul>
	</li>
</ul>

Passed Example 6

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The programmatically determined link context (provided by the table header assigned to the cell containing the link) and the accessible name (from the link’s text) describe the purpose of the links.

<table>
	<tr>
		<th colspan="3">Ulysses</th>
	</tr>
	<tr>
		<td><a href="https://www.gutenberg.org/files/4300/4300-h/4300-h.htm">HTML</a></td>
		<td>
			<a href="https://www.gutenberg.org/ebooks/4300.epub.images?session_id=04cd710372888de8d8d322215cdfe8ce5b0f8d73"
				>EPUB</a
			>
		</td>
		<td><a href="https://www.gutenberg.org/files/4300/4300-0.txt">Plain text</a></td>
	</tr>
</table>

Passed Example 7

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The accessible name describes the purpose of the link.

<p id="instructions">Go to the main content.</p>
<svg xmlns="http://www.w3.org/2000/svg" x="0" y="0">
	<a href="#main" aria-labelledby="instructions">
		<path
			style="fill:#1E201D;"
			d="M21.205,5.007c-0.429-0.444-1.143-0.444-1.587,0c-0.429,0.429-0.429,1.143,0,1.571l8.047,8.047H1.111
			C0.492,14.626,0,15.118,0,15.737c0,0.619,0.492,1.127,1.111,1.127h26.554l-8.047,8.032c-0.429,0.444-0.429,1.159,0,1.587
			c0.444,0.444,1.159,0.444,1.587,0l9.952-9.952c0.444-0.429,0.444-1.143,0-1.571L21.205,5.007z"
		/>
	</a>
</svg>

<main>
	<p id="main">This is the main content.</p>
</main>

Passed Example 8

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The programmatically determined link context (provided by the cell containing the link) and the accessible name (from the link’s text) describe the purpose of the links.

<table>
	<tr>
		<td>
			Download Ulysses in
			<a href="https://www.gutenberg.org/files/4300/4300-h/4300-h.htm">HTML</a>
		</td>
		<td>
			Download Ulysses in
			<a href="https://www.gutenberg.org/ebooks/4300.epub.images?session_id=04cd710372888de8d8d322215cdfe8ce5b0f8d73"
				>EPUB</a
			>
		</td>
	</tr>
</table>

Passed Example 9

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The programmatically determined link context (provided by the element referenced by the aria-describedby attribute) and the accessible name (from the link’s text) describe the purpose of the links.

<h2 id="rule">Button has accessible name</h2>
<ul>
	<li><a href="https://act-rules.github.io/rules/97a4e1#applicability" aria-describedby="rule">Applicability</a></li>
	<li><a href="https://act-rules.github.io/rules/97a4e1#expectation" aria-describedby="rule">Expectation</a></li>
</ul>

Failed

Failed Example 1

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The accessible name (from the link’s text), together with the absence of programmatically determined link context, does not describe the purpose of the link.

<a href="#desc">More</a>

<p id="desc">This product consists of several web pages.</p>

Failed Example 2

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The accessible name (from the link’s text), together with the absence of programmatically determined link context, does not describe the purpose of the link.

<div role="link" tabindex="0" onclick="document.location+='#main'">More</div>

<main>
	<p id="main">This is the main content.</p>
</main>

Failed Example 3

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The accessible name (from the link’s text), together with the absence of programmatically determined link context, does not describe the purpose of the link.

<svg xmlns="http://www.w3.org/2000/svg" x="0" y="0">
	<a href="#main">
		<text x="20" y="20">
			Go
		</text>
	</a>
</svg>

<main>
	<p id="main">This is the main content.</p>
</main>

Failed Example 4

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The accessible name (from the link’s text) does not describe the purpose of the link. The other information available on the page is not programmatically determined link context because it is in a different p element.

<p>
	The W3C held a workshop on June 9-10, 2005 at DERI Innsbruck (Austria), to gather information about potential
	standardization work on Semantics in Web Services.
</p>

<p><a href="https://www.w3.org/2005/04/FSWS/workshop-report.html">Workshop</a></p>

Failed Example 5

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The accessible name (from the link’s text) does not describe the purpose of the link. The other information available on the page is not programmatically determined link context because it is outside the list where the links are.

<p style="font-weight: bold">Ulysses</p>
<ul>
	<li><a href="https://www.gutenberg.org/files/4300/4300-h/4300-h.htm"> HTML </a></li>
	<li>
		<a href="https://www.gutenberg.org/ebooks/4300.epub.images?session_id=04cd710372888de8d8d322215cdfe8ce5b0f8d73">
			EPUB
		</a>
	</li>
	<li><a href="https://www.gutenberg.org/files/4300/4300-0.txt"> Plain text </a></li>
</ul>

Failed Example 6

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The accessible name (from the link’s text) does not describe the purpose of the link. The other information available on the page is not programmatically determined link context because it not available on the same cell of the link or in a header cell for that cell.

<table>
	<tr>
		<th colspan="3">Books</th>
	</tr>
	<tr>
		<td>Ulysses</td>
		<td><a href="https://www.gutenberg.org/files/4300/4300-h/4300-h.htm">Download</a></td>
		<td>1.61MB</td>
	</tr>
</table>

Inapplicable

Inapplicable Example 1

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An a element with its semantic role changed from link to another role.

<a href="https://www.w3.org/WAI" role="button">Web Accessibility Initiative (WAI)</a>

Inapplicable Example 2

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The link element is not included in the accessibility tree.

<a href="https://www.w3.org/WAI" style="display: none;"
	><img src="/test-assets/5effbb/cart.svg" alt="Checkout" />Checkout</a
>

Inapplicable Example 3

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This a element is not a semantic link, because it has no href attribute.

<a>placeholder</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

An element is focusable if one or both of the following are true:

Exception: Elements that lose focus during a period of up to 1 second after gaining focus, without the user interacting with the page the element is on, are not considered focusable.

Notes:

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.

Inheriting Semantic Role

An element with an inheriting semantic role of X is any element with a non-abstract semantic role that inherits from X, or is the same as X.

Example: An “inheriting semantic link” is any element that either has the semantic role of link or a semantic role that inherits from the link role, such as doc-biblioref.

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.

The programmatically determined context of a link (or programmatically determined link context) is the set of all elements that are included in the accessibility tree, and have one or more of the following relationships to the link:

This definition is based on the WCAG definition of programmatically determined link context.

This definition assumes that the HTML document with the link is a document using HTML according to the specification.

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

Note: The HTML standard suggests setting the CSS display property to none for elements with the hidden attribute. While not required by HTML, all modern browsers follow this suggestion. Because of this the hidden attribute is not used in this definition. In browsers that use this suggestion, overriding the CSS display property can reveal elements with the hidden attribute.

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.

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.

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
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/.