Object element rendering non-text content has non-empty accessible name

  • Rule Type:atomic
  • Rule Id: 8fc3b6
  • Last modified: Oct 19, 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.

Description

This rule checks that each object element rendering non-text content has a non-empty accessible name.

Applicability

This rule applies to any object element that is included in the accessibility tree and embeds a resource with an image MIME type or an audio or video MIME type.

Expectation

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

Assumptions

The object element is not rendered for presentational purposes. If the object is decorative and not marked as decorative then the rule might fail but the success criterion might still be satisfied.

Accessibility Support

Non-supported media formats make screen readers render the text content of the element instead of other attributes.

Background

Testing that the accessible name describes the purpose of the object element is not part of this rule and must be tested separately.

Test Cases

Passed

Passed Example 1

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This object element which embeds an audio resource has a non-empty accessible name through its aria-label attribute.

<object aria-label="Moon speech" data="/test-assets/moon-audio/moon-speech.mp3"></object>

Passed Example 2

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This object element which embeds a video resource has a non-empty accessible name through its title attribute.

<object title="Rabbit animated short" data="/test-assets/rabbit-video/video.mp4"></object>

Passed Example 3

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This object element which embeds an image resource has a non-empty accessible name through its aria-labelledby attribute.

<span id="label">W3C</span> <object aria-labelledby="label" data="/test-assets/shared/w3c-logo.png"></object>

Passed Example 4

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This object element placed off screen, which embeds an audio resource, has a non-empty accessible name through its title attribute.

<html>
	<style>
		.offScreen {
			position: absolute;
			left: -9999px;
			top: -9999px;
		}
	</style>
	<body>
		<object title="Moon speech" data="/test-assets/moon-audio/moon-speech.mp3" class="offScreen"></object>
	</body>
</html>

Failed

Failed Example 1

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This object element which embeds a video resource has an empty accessible name because the title attribute is empty.

<object title="" data="/test-assets/rabbit-video/video.mp4"></object>

Failed Example 2

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This object element which embeds an image resource has an empty accessible name because the span element with id="label" is empty.

<span id="label"></span> <object aria-labelledby="label" data="/test-assets/shared/w3c-logo.png"></object>

Failed Example 3

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This object element which embeds an audio resource has an empty accessible name because the aria-labelledby attribute references a non-existing id.

<object aria-labelledby="download" data="/test-assets/moon-audio/moon-speech.mp3"></object>

Failed Example 4

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This object element which embeds an audio resource has an empty accessible name because it does not provide an accessible name through one of title, aria-label or aria-labelledby attributes.

<object data="/test-assets/moon-audio/moon-speech.mp3"></object>

Inapplicable

Inapplicable Example 1

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This object element is not included in the accessibility tree due to display:none.

<object data="/test-assets/rabbit-video/video.mp4" style="display: none;"></object>

Inapplicable Example 2

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This object element is not included in the accessibility tree due to visibility:hidden.

<object data="/test-assets/moon-audio/moon-speech.mp3" style="visibility: hidden;"></object>

Inapplicable Example 3

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This object element is not included in the accessibility tree due to aria-hidden="true".

<object data="/test-assets/shared/w3c-logo.png" aria-hidden="true"></object>

Inapplicable Example 4

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This object element is not included in the accessibility tree because it is marked as decorative through role="presentation".

<object type="image/png" role="presentation" data="/test-assets/contrast/example.png"></object>

Inapplicable Example 5

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This object element embeds an HTML resource.

<object title="My University" data="/test-assets/shared/index.html"></object>

Inapplicable Example 6

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There is no object element.

<audio title="Moon speech" src="/test-assets/moon-audio/moon-speech.mp3"></audio>

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.

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 of none; or
  • has a computed CSS property visibility of hidden; or
  • has an aria-hidden attribute set to true

In any other case, the element's hidden state is "false".

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 or presentation; or
  • it is an img element with an alt 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.


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

Audio file

  • audio is an excerpt from JFK's 'Moon Speech'
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