Heading has non-empty accessible name

  • Rule Type:atomic
  • Rule Id: ffd0e9
  • Last modified: Jun 03, 2020
  • Accessibility Requirements Mapping:
    • 1.3.1 Info and Relationships (Level: A)
      • Learn More about 1.3.1 (Info and Relationships)
      • Required for conformance to WCAG 2.0 and above on level A and above.
      • 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.
    • 2.4.6 Headings and Labels (Level: AA)
      • Learn More about 2.4.6 (Headings and Labels)
      • Required for conformance to WCAG 2.0 and above on level AA and above.
      • 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.

Description

This rule checks that each heading has a non-empty accessible name.

Applicability

This rule applies to any HTML element with the semantic role of heading that is included in the accessibility tree.

Expectation

Each test target has a non-empty ("") accessible name.

Assumptions

There are currently no assumptions.

Accessibility Support

  • Some assistive technologies may hide headings with empty accessible name from the users. This depends both on the user agent and how the accessible name was computed (the accessible name and description computation is not clear concerning which characters should be trimmed) and of the assistive technology itself. Hence, there are cases where the outcome of this rule is failed, but users of certain assistive technology and browser combinations will not experience an issue.

Note: Completely empty headings (<h1></h1>) seem to be consistently ignored by assistive technologies. However, they fail Technique H42: Using h1-h6 to identify headings (by using heading markup for content which is not heading). Moreover, they may be rendered on screen (by breaking flow content, or because of custom styling), thus causing concerns for sighted users. Therefore, this rule also fails on these.

  • 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 heading and fail this rule with some technology but users of other technologies would not experience any accessibility issue.

Background

Test Cases

Passed

Passed Example 1

Open in a new tab

This h1 element has a non-empty accessible name.

<h1>ACT rules</h1>

Passed Example 2

Open in a new tab

This div element has a semantic role of heading and a non-empty accessible name.

<div role="heading" aria-level="1">ACT rules</div>

Passed Example 3

Open in a new tab

This h1 element has an non-empty accessible name given by the aria-labelledby attribute. Its content is hidden from assistive technologies.

<span id="h-name">ACT rules</span>
<h1 aria-labelledby="h-name"><span aria-hidden="true">Learn about ACT rules</span></h1>

Passed Example 4

Open in a new tab

This h1 element has an non-empty accessible name given by the alt attribute of its content.

<h1><img src="#" alt="ACT rules" /></h1>

Passed Example 5

Open in a new tab

Even though this h1 element is not visible, it is still included in the accessibility tree. It has a non-empty accessible name.

<h1 style="position: absolute; top: -9999px">ACT rules</h1>

Failed

Failed Example 1

Open in a new tab

This h1 element has an empty accessible name given by its aria-labelledby attribute.

<span id="label"></span>
<h1 aria-labelledby="label">ACT rules</h1>

Failed Example 2

Open in a new tab

This h1 element has an empty accessible name because the img element has a semantic role of presentation, and thus does not provide an accessible name to the h1 element. Note that the alt attribute does not trigger Presentational Roles Conflict Resolution because it is not an ARIA attribute.

<h1><img src="#" alt="ACT rules" role="presentation" /></h1>

Failed Example 3

Open in a new tab

This h1 element has an empty accessible name because the spaces and line break are trimmed by accessible name computation.

<h1><br /></h1>

Failed Example 4

Open in a new tab

This h1 element has an empty accessible name. It is nonetheless rendered by breaking the flow content, resulting in confusing situation for sighted users.

<span>Hello</span>
<h1></h1>
<span>World!</span>

Failed Example 5

Open in a new tab

This div element with a semantic role of heading has an empty accessible name (and content). It is nonetheless rendered due to its styling, resulting in confusing situation for sighted users.

<div role="heading" aria-level="1" style="border-style: solid"></div>

Failed Example 6

Open in a new tab

This h1 element has an explicit role of none. However, the global property aria-labelledby is specified. Thus it has a semantic role of heading due to Presentational Roles Conflict Resolution. It has an empty accessible name given by its aria-labelledby attribute.

<span id="label"></span>
<h1 aria-labelledby="label" role="none">ACT rules</h1>

Inapplicable

Inapplicable Example 1

Open in a new tab

No element has a semantic role of heading.

<div></div>

Inapplicable Example 2

Open in a new tab

This h1 element is not included in the accessibility tree.

<h1 aria-hidden="true"></h1>

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).

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.

Accessibility Support for Accessible Name

  • Because the accessible name and description computation is not clear about which whitespace are considered, browsers behave differently when trimming and flattening the accessible name. For example, some browsers completely trim non-breaking spaces while some keep them in the accessible name.
  • There exists a popular browser which does not perform the same trimming and flattening depending whether the accessible name comes from content, an aria-label attribute, or an alt attribute.
  • There exists a popular browser which assign no accessible name (null) when none is provided, instead of assigned an empty accessible name ("").

Examples for Accessible Name

Note: The examples presented here are non-normative and not testable. They serve to illustrate some common pitfalls about the definition and to help implementers of ACT rules understand it.

The input elements have an accessible name of, respectively, "Billing Name" and "Billing Address". These accessible names are given by the aria-labelledby attributes and associated elements.

<div id="myBillingId">Billing</div>

<div>
	<div id="myNameId">Name</div>
	<input type="text" aria-labelledby="myBillingId myNameId" />
</div>
<div>
	<div id="myAddressId">Address</div>
	<input type="text" aria-labelledby="myBillingId myAddressId" />
</div>

This button element has an accessible name of "Share ACT rules" given by its aria-label attribute.

<button aria-label="Share ACT rules">Share</button>

This img element has an accessible name of "ACT rules" given by its alt attribute.

<img src="#" alt="ACT rules" />

The button element has an accessible name of "Share ACT rules" given by the enclosing label element (implicit label)

<label>Share ACT rules<button>Share</button></label>

The button element has an accessible name of "Share ACT rules" given by the associated label element (explicit label)

<label for="act-rules">Share ACT rules</label><button id="act-rules"></button>

This a element has an accessible name of "ACT rules" given from its content. Note that not all semantic roles allow name from content.

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

This span element has an empty accessible name ("") because span does not allow name from content.

<span>ACT rules</span>

This span element has an empty accessible name ("") because span is not a labelable element.

<label>ACT rules<span></span></label>

Note: When the same element can have an accessible name from several sources, the order of precedence is: aria-labelledby, aria-label, own attributes, label element, name from content. The examples here are listed in the same order.

Note: For more examples of accessible name computation, including many tricky cases, check the Accessible Name Testable Statements.

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.

Accessibility Support for Explicit Semantic Role

Some browsers and assistive technologies treat the tokens of the role attribute as case-sensitive. Unless lowercase letters are used for the value of the role attribute, not all user agents will be able to interpret the tokens correctly. ARIA in HTML (working draft) also specifies that authors must use lowercase letters for the role and aria-* attributes.

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).

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 with using sequential keyboard navigation regardless of the assistive technologies used, even though the element would not be included in the accessibility tree.

Examples for Included in the accessibility tree

Note: The examples presented here are non-normative and not testable. They serve to illustrate some common pitfalls about the definition and to help implementers of ACT rules understand it.

This span element is included in the accessibility tree (by default, elements are included in the accessibility tree).

<span>ACT rules</span>

This span element is not included in the accessibility tree because it is hidden to everybody by the CSS property.

<span style="display:none">ACT rules</span>

This span element is not included in the accessibility tree because it is explicitly removed by the aria-hidden attribute.

<span aria-hidden="true">ACT rules</span>

This span element is positioned off screen, hence is not visible, but is nonetheless included in the accessibility tree.

<span style="position: absolute; top:-9999em">ACT rules</span>

Although the span element with an id of "label" is not itself included in the accessibility tree, it still provides an accessible name to the other span, via the aria-labelledby attribute. Thus, it is still indirectly exposed to users of assistive technologies. Removing an element from the accessibility tree is not enough to remove all accessibility concerns from it since it can still be indirectly exposed.

<span id="label" style="display:none">ACT rules</span>
<span aria-labelledby="label">Accessibility Conformance Testing rules</span>

Although this input element is not included in the accessibility tree, it is still focusable, hence users of assistive technologies can still interact with it by sequential keyboard navigation. This may result in confusing situations for such users (and is in direct violation of the fourth rule of ARIA (working draft)).

<input type="text" aria-hidden="true" name="fname" />

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:

  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.

Accessibility Support for Definition of Semantic Role for Semantic Role

  • There exist popular web browsers and assistive technologies which do not correctly implement Presentational Roles Conflict Resolution. These technologies will not include in the accessibility tree elements that should be, according to Specifications. Thus, some elements that should have their semantic role fixed by case Conflict above are instead falling into case Explicit and are hidden for users of assistive technologies.
  • A similar conflict exists for focusable elements with a aria-hidden="true" attribute. The WAI ARIA specification does not explain how to solve it. Some browsers give precedence to the element being focusable (and expose it in the accessibility tree) while some give precedence to the aria-hidden attribute (and hide the element).

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.

Examples for Visible

Note: The examples presented here are non-normative and not testable. They serve to illustrate some common pitfalls about the definition and to help the implementers of ACT rules understand it.

This span element is visible (by default, elements are visible).

<span>Now you can see me!</span>

This span element is not visible because of the CSS visibility property.

<span style="visibility: hidden">I'm the invisible man</span>

This span element is not visible because of the CSS display property.

<span style="display: none">I'm the invisible man</span>

This span element is not visible because it is positioned off-screen

<span style="position: absolute; top: -9999px; left: -9999px;">Incredible how you can</span>

This span element is not visible because it contains only whitespace and line breaks.

<span>
	<br />
	&nbsp;
</span>

This span element is not visible because it has the exact same color as its background.

<span style="color: #00F; background: #00F;">See right through me</span>

Useful Links


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. This section will not be included in the rule when it is published on the W3C website.

ToolConsitencyCompleteReport
AlfaconsistentYesView Report
QualWebconsistentYesView Report
SortSiteconsistentYesView Report

Acknowledgments

Table of Contents