Link has non-empty accessible name
- Rule Type:
- atomic
- Rule ID:
- c487ae
- Last Modified:
- Oct 12, 2020
- Accessibility Requirements Mapping:
- 4.1.2 Name, Role, Value (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
- Any
- 2.4.4 Link Purpose (In Context) (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
- Any
- 2.4.9 Link Purpose (Link Only) (Level AAA)
- 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
- G91: Providing link text that describes the purpose of a link
- 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
- Any
- Input Aspects:
- Accessibility Tree
- DOM Tree
- CSS Styling
Description
This rule checks that each link has a non-empty accessible name.
Applicability
The rule applies to any HTML element with the semantic role of link
that is included in the accessibility tree.
Expectation
Each target element has an accessible name that is not empty (""
).
Assumptions
The rule assumes that all links are user interface components as defined by WCAG 2. When the link role is used on elements that do not behave as links, failing this rule might not mean that the success criteria are failed.
Accessibility Support
- There are assistive technologies that do not support using the
title
attribute for an accessible name, or in which this feature can be disabled. - For
area
elements that have anhref
attribute, but are not nested inside amap
element, there are differences between browsers and assistive technology on if thearea
is included in the accessibility tree. - Implementation of Presentational Roles Conflict Resolution varies from one browser or assistive technology to another. Depending on this, some elements can have a semantic role of
link
and fail this rule with some technology but users of other technologies would not experience any accessibility issue.
Background
- Understanding Success Criterion 2.4.4: Link Purpose (In Context)
- ARIA7: Using aria-labelledby for link purpose
- ARIA8: Using aria-label for link purpose
- Understanding Success Criterion 4.1.2: Name, Role, Value
- F89: Failure of Success Criteria 2.4.4, 2.4.9 and 4.1.2 due to not providing an accessible name for an image which is the only content in a link
Test Cases
Passed
Passed Example 1
This a
element has an accessible name from its content.
<a href="https://www.w3.org/WAI"> Web Accessibility Initiative (WAI) </a>
Passed Example 2
This div
element has an explicit semantic role of link
and an accessible name from its content.
<div role="link" onclick="window.location.href='https://www.w3.org/WAI/'">Web Accessibility Initiative (WAI)</div>
Passed Example 3
This button
element has an explicit semantic role of link
and an accessible name from its content.
<button role="link" onclick="window.location.href='https://www.w3.org/WAI/'">Click me for WAI!</button>
Passed Example 4
This a
element has an accessible name via aria-label
<a href="https://www.w3.org/WAI"
><img src="/test-assets/shared/w3c-logo.png" aria-label="Web Accessibility Initiative"
/></a>
Passed Example 5
This a
element has an accessible name via title
.
<a href="https://www.w3.org/WAI" title="Web Accessibility Initiative"
><img src="/test-assets/shared/w3c-logo.png" alt=""
/></a>
Passed Example 6
This a
element has an accessible name from its content via the title
on the img
element.
<a href="https://www.w3.org/WAI"><img src="/test-assets/shared/w3c-logo.png" title="Web Accessibility Initiative"/></a>
Passed Example 7
This a
element has an accessible name from its content.
<a href="https://www.w3.org/WAI"
><img src="/test-assets/shared/w3c-logo.png" alt="" />Web Accessibility Initiative (WAI)</a
>
Passed Example 8
This a
element has an accessible name from its content via aria-labelledby
on the img
element.
<a href="https://www.w3.org/WAI"><img src="/test-assets/shared/w3c-logo.png" aria-labelledby="id1"/></a>
<div id="id1">Web Accessibility Initiative (WAI)</div>
Passed Example 9
This a
element placed off screen has an accessible name from its content.
<html>
<style>
.offScreenLink {
position: absolute;
left: -9999px;
top: -9999px;
}
</style>
<body>
<a class="offScreenLink" href="https://www.w3.org/WAI">Web Accessibility Initiative (WAI)</a>
</body>
</html>
Passed Example 10
This area
element has a semantic role of link
and an accessible name via alt
.
<img src="/test-assets/c487ae/planets.jpg" width="145" height="126" alt="Planets" usemap="#planetmap" />
<map name="planetmap">
<area shape="rect" coords="0,0,30,100" href="sun.htm" alt="Sun" />
</map>
Failed
Failed Example 1
This a
element has an empty accessible name.
<a href="http://www.w3.org/WAI"></a>
Failed Example 2
This a
element with an image has an empty accessible name. The image is decorative and is marked as such with an empty alt
attribute value.
<a href="https://www.w3.org/WAI"><img src="/test-assets/shared/w3c-logo.png" alt=""/></a>
Failed Example 3
This a
element with an image has an empty accessible name. The image is decorative because it has a role
attribute value of presentation
.
<a href="http://www.w3.org/WAI"><img src="/test-assets/shared/w3c-logo.png" role="presentation"/></a>
Failed Example 4
This a
element with an image has an empty accessible name. The image is decorative because it has a role
attribute value of none
.
<a href="http://www.w3.org/WAI"><img src="/test-assets/shared/w3c-logo.png" role="none"/></a>
Failed Example 5
This a
element with an img
with an empty title
has an empty accessible name.
<a href="https://www.w3.org/WAI"><img src="/test-assets/shared/w3c-logo.png" title=""/></a>
Failed Example 6
This a
element with an img
with an aria-labelledby
has an empty accessible name.
<a href="https://www.w3.org/WAI"><img src="/test-assets/shared/w3c-logo.png" aria-labelledby="id1"/></a>
<div id="id1"></div>
Failed Example 7
This a
element with an img
with an aria-labelledby
referencing a non-existing id has an empty accessible name.
<a href="https://www.w3.org/WAI"><img src="/test-assets/shared/w3c-logo.png" aria-labelledby="id1"/></a>
Failed Example 8
This a
element placed off screen has an empty accessible name.
<a href="https://www.w3.org/WAI" style="left: -9999px; position: absolute;">
<img src="/test-assets/shared/w3c-logo.png" />
</a>
Failed Example 9
This area
element has a semantic role of link
and an empty accessible name.
<img src="/test-assets/c487ae/planets.jpg" width="145" height="126" alt="Planets" usemap="#planetmap" />
<map name="planetmap">
<area shape="rect" coords="0,0,82,126" href="sun.htm" />
</map>
Failed Example 10
This a
element has an explicit role of none
. However, it is focusable (by default). Thus it has a semantic role of link
due to Presentational Roles Conflict Resolution. It has an empty accessible name.
<a href="https://www.w3.org/WAI" role="none"> </a>
Inapplicable
Inapplicable Example 1
This a
element does not have a semantic role of link
because it has been changed to button
.
<a href="https://www.w3.org/WAI" role="button">
Web Accessibility Initiative (WAI)
</a>
Inapplicable Example 2
This a
element is not included in the accessibility tree due to display: none
.
<a href="https://www.w3.org/WAI" style="display: none;"><img src="/test-assets/shared/w3c-logo.png"/></a>
Inapplicable Example 3
This a
element is not included in the accessibility tree due to visibility: hidden
.
<a href="https://www.w3.org/WAI" style="visibility: hidden;">Some text</a>
Inapplicable Example 4
This a
element is not included in the accessibility tree due to aria-hidden="true"
.
<a aria-hidden="true" href="https://www.w3.org/WAI">
Web Accessibility Initiative (WAI)
</a>
Inapplicable Example 5
This area
element does not have the role of link because it does not have an href
attribute.
<area shape="rect" coords="0,0,82,126" />
Inapplicable Example 6
This a
element does not have the role of link because it does not have an href
attribute.
<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.
Attribute value
The attribute value of a content attribute set on an HTML element is the value that the attribute gets after being parsed and computed according to specifications. It may differ from the value that is actually written in the HTML code due to trimming whitespace or non-digits characters, default values, or case-insensitivity.
Some notable case of attribute value, among others:
- For enumerated attributes, the attribute value is either the state of the attribute, or the keyword that maps to it; even for the default states. Thus
<input type="image" />
has an attribute value of eitherImage Button
(the state) orimage
(the keyword mapping to it), both formulations having the same meaning; similarly, “an input element with atype
attribute value ofText
” can be either<input type="text" />
,<input />
(missing value default), or<input type="invalid" />
(invalid value default). - For boolean attributes, the attribute value is
true
when the attribute is present andfalse
otherwise. Thus<button disabled>
,<button disabled="disabled">
and<button disabled="">
all have adisabled
attribute value oftrue
. - For attributes whose value is used in a case-insensitive context, the attribute value is the lowercase version of the value written in the HTML code.
- For attributes that accept numbers, the attribute value is the result of parsing the value written in the HTML code according to the rules for parsing this kind of number.
- For attributes that accept sets of tokens, whether space separated or comma separated, the attribute value is the set of tokens obtained after parsing the set and, depending on the case, converting its items to lowercase (if the set is used in a case-insensitive context).
- For
aria-*
attributes, the attribute value is computed as indicated in the WAI-ARIA specification.
This list is not exhaustive, and only serves as an illustration for some of the most common cases.
The attribute value of an IDL attribute is the value returned on getting it. Note that when an IDL attribute reflects a content attribute, they have the same attribute value.
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:
- has a
hidden
attribute; or - has a computed CSS property
display
ofnone
; or - has a computed CSS property
visibility
ofhidden
; or - has an
aria-hidden
attribute set totrue
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:
- 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 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:
- 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.
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 its hidden state is false, 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.
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.
Acknowledgements
This rule was written in the ACT Rules community group, with the support of the EU-funded WAI-Tools Project.
Authors
Image
- Image used in passed example 10 and failed example 9 is courtesy of NASA/JPL-Caltech.
Changelog
This is the first version of this ACT rule.
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