svg element with explicit role has non-empty accessible name

  • Rule Type:atomic
  • Rule Id: 7d6734
  • Last modified: Oct 12, 2020
  • Accessibility Requirements Mapping:
    • 1.1.1 Non-text Content (Level A)
      • Learn More about 1.1.1 Non-text Content
      • 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.
  • Input Aspects:

Description

This rule checks that each SVG image element that is explicitly included in the accessibility tree has a non-empty accessible name.

Applicability

The rule applies to any element in the SVG namespace with an explicit semantic role of either img, graphics-document, graphics-symbol, that is included in the accessibility tree.

Expectation

Each target element has an accessible name that is not empty.

Assumptions

This rule assumes that the presence of one of the roles outlined in the applicability indicates the authors intent to include the element in the accessibility tree and thus convey information to the user about that element.

Accessibility Support

The HTML Accessibility API Mappings specify that the <svg> element has an implicit role of graphics-document. However browser support for the graphics-document role and the SVG Accessibility API Mappings is inconsistent.

This rule is limited to the explicit use of roles, as a clear indication that content should convey meaning, until the SVG Accessibility API Mappings is more stable and browser support is more consistent.

Browser and assistive technology support for SVG <title> and <desc> elements is currently inconsistent. Using WAI ARIA in combination with the img role for non-decorative <svg> elements significantly improves accessibility browser support.

Until browser support for the SVG Accessibility API Mappings is more consistent it is recommended to explicitly remove decorative <svg> elements from the accessibility tree.

Background

Test Cases

Passed

Passed Example 1

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This svg element has an explicit role of img and an accessible name from the title element that is not empty.

<p>How many circles are there?</p>
<svg xmlns="http://www.w3.org/2000/svg" role="img" width="100" height="100">
	<title>1 circle</title>
	<circle cx="50" cy="50" r="40" fill="yellow"></circle>
</svg>

Passed Example 2

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This circle element has an explicit role of graphics-symbol and an accessible name from the aria-label attribute that is not empty.

<p>How many circles are there?</p>
<svg xmlns="https://www.w3.org/2000/svg">
	<circle
		role="graphics-symbol"
		cx="50"
		cy="50"
		r="40"
		stroke="green"
		stroke-width="4"
		fill="yellow"
		aria-label="1 circle"
	></circle>
</svg>

Passed Example 3

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This svg element has an explicit role of graphics-document and an accessible name from the title element that is not empty.

<p>How many circles are there?</p>
<svg xmlns="http://www.w3.org/2000/svg" role="graphics-document" width="100" height="100">
	<title>1 circle</title>
	<circle cx="50" cy="50" r="40" fill="yellow"></circle>
</svg>

Failed

Failed Example 1

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This svg element has an explicit role of img but has an empty ("") accessible name.

<p>How many circles are there?</p>
<svg xmlns="http://www.w3.org/2000/svg" role="img">
	<circle cx="50" cy="50" r="40" stroke="green" stroke-width="4" fill="yellow"></circle>
</svg>

Failed Example 2

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This svg element has an explicit role of img, is included in the accessibility tree, but it has an empty ("") accessible name because the title element is empty.

<p>How many circles are there?</p>
<svg xmlns="http://www.w3.org/2000/svg" role="img">
	<title></title>
	<circle cx="50" cy="50" r="40" fill="yellow"></circle>
</svg>

Failed Example 3

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This circle element has an explicit role of graphics-symbol but has an empty ("") accessible name.

<p>How many circles are there?</p>
<svg xmlns="http://www.w3.org/2000/svg">
	<circle role="graphics-symbol" cx="50" cy="50" r="40" stroke="green" stroke-width="4" fill="yellow"></circle>
</svg>

Failed Example 4

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This svg element with an explicit role of img has an empty ("") accessible name. The SVG text element is not used in computing the accessible name.

<p>How many circles are there?</p>
<svg xmlns="http://www.w3.org/2000/svg" role="img" width="100" height="100">
	<circle cx="50" cy="50" r="40" fill="yellow"></circle>
	<text x="50%" y="50%" dominant-baseline="middle" text-anchor="middle">
		1 circle
	</text>
</svg>

Inapplicable

Inapplicable Example 1

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Neither the svg element nor the circle element has any of the three explicit roles of img, graphics-document, graphics-symbol.

<svg xmlns="http://www.w3.org/2000/svg">
	<circle cx="50" cy="50" r="40" fill="yellow"></circle>
</svg>

Inapplicable Example 2

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This svg element and its descendants are not included in the accessibility tree because of the aria-hidden attribute.

<svg xmlns="http://www.w3.org/2000/svg" role="img" aria-hidden="true">
	<circle cx="50" cy="50" r="40" fill="yellow"></circle>
</svg>

Inapplicable Example 3

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This circle element has an explicit role that is neither img, graphics-document nor graphics-symbol.

<svg xmlns="http://www.w3.org/2000/svg">
	<circle role="graphics-object" cx="50" cy="50" r="40" fill="yellow"></circle>
</svg>

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.

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 ("").
  • The accessible name and description computation suggest that if an aria-labelledby attribute refers to an existing but empty element, the computation should stop and return an empty name without defaulting to the next steps. Several user agents and assistive technologies chose to use the next step in the computation in this case.

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).

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.

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.


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.

ToolConsistencyCompleteReport
AlfaconsistentYesView Report
axe-coreconsistentYesView Report
QualWebconsistentYesView Report
SortSiteconsistentYesView Report

Acknowledgments

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