Proposed Link is descriptive
Description
This rule checks that the accessible name of a link describes its purpose.
Applicability
This rule applies to any inheriting semantic link
for which all the following is true:
- the link is included in the accessibility tree; and
- the link has a non-empty (
""
) accessible name.
Expectation
Each test target has an accessible name which describes its purpose.
Assumptions
- This rule assumes that the purpose of the link is not ambiguous to users in general when seen in context on the web page, which is the exception mentioned in Success Criterion 2.4.9 Link Purpose (Link Only). If the link is ambiguous to users in general, users of assistive technologies are not at a disadvantage when viewing the link out of context.
- This rule assumes that all semantic
link
elements are used as links. An element marked up as a link, but that does not behave as a link would not fail Success Criterion 2.4.9 Link Purpose (Link Only).
Accessibility Support
- Implementation of Presentational Roles Conflict Resolution varies from one browser or assistive technology to another. Depending on this, some semantic
link
elements can fail this rule with some technology but users of other technologies would not experience any accessibility issue.
Background
Related rules
Bibliography
- Understanding Success Criterion 2.4.9: Link Purpose (Link Only)
- G91: Providing link text that describes the purpose of a link
- H30: Providing link text that describes the purpose of a link for anchor elements
- H24: Providing text alternatives for the area elements of image maps
- ARIA7: Using aria-labelledby for link purpose
- ARIA8: Using aria-label for link purpose
Accessibility Requirements Mapping
2.4.9 Link Purpose (Link Only) (Level AAA)
- Learn more about 2.4.9 Link Purpose (Link Only)
- Required for conformance to WCAG 2.0 and later on level AAA.
- 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
- Any
Input Aspects
The following aspects are required in using this rule.
Test Cases
Passed
Passed Example 1
This a
element has an accessible name from its text that describes its purpose.
<a href="#desc">See the description of this product.</a>
<p id="desc">This product consists of several web pages.</p>
Passed Example 2
This a
element has an accessible name from the alt
attribute on its img
element that describes its purpose.
<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
This span
element has an explicit role of link
and an accessible name from its text that describes its purpose.
<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 4
This a
element has an accessible name from its aria-labelledby
attribute that describes its purpose.
<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>
Failed
Failed Example 1
This link has an accessible name which does not describe its purpose.
<a href="#desc">More</a>
<p id="desc">This product consists of several web pages.</p>
Failed Example 2
This link has an accessible name which does not describe its purpose.
<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
This link has an accessible name which does not describe its purpose.
<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
This link has an accessible name which, alone, does not describe its purpose.
<p>See the description of <a href="#desc">this product</a>.</p>
<p id="desc">This product consists of several web pages.</p>
Failed Example 5
These links have accessible names which, alone, do not describe their purpose.
<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>
Inapplicable
Inapplicable Example 1
There is no inheriting semantic link
in this document.
<a href="https://www.w3.org/WAI" role="button">Web Accessibility Initiative (WAI)</a>
Inapplicable Example 2
This link 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
There is no inheriting semantic link
in this document (a
element without an href
attribute do not have a role of link
).
<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:
- the element is part of sequential focus navigation; or
- the element has a tabindex value that is not null.
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:
- The 1 second time span is an arbitrary limit which is not included in WCAG. Given that scripts can manage the focus state of elements, testing the focusability of an element consistently would be impractical without a time limit.
- The tabindex value of an element is the value of the tabindex attribute parsed using the rules for parsing integers. For the tabindex value to be different from null, it needs to be parsed without errors.
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:
- it has an explicit role of
none
orpresentation
; or - it is an
img
element with analt
attribute whose value is the empty string (alt=""
), and with no explicit role.
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:
- Inapplicable: No part of the test subject matches the applicability
- Passed: A test target meets all expectations
- Failed: A test target does not meet all expectations
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:
- has a computed CSS property
display
ofnone
; or - has an
aria-hidden
attribute set totrue
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:
- 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.
- Explicit If the element has an explicit role, then its semantic role is its explicit role.
- 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:
- Accessible Rich Internet Applications (WAI-ARIA) 1.1
- WAI-ARIA Graphics Module 1.0
- Digital Publishing WAI-ARIA Module 1.0
Note: depending on the type of content being evaluated, part of the specifications might be irrelevant and should be ignored.
Rule Versions
This is the first version of this ACT rule.
Implementations
There are currently no known implementations for this rule. If you would like to contribute an implementation, please read the ACT Implementations page for details.