Proposed Test Rule: Object element rendering non-text content has non-empty accessible name

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

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

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

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

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

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

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

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

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

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

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

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

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

This object element embeds an HTML resource.

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

Inapplicable Example 6

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.

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:

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. [examples of included in the accessibility tree]: https://act-rules.github.io/pages/examples/included-in-the-accessibility-tree/

Marked as decorative

An element is marked as decorative if one or more of the following conditions is true:

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:

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.

WAI-ARIA specifications

The WAI ARIA Specifications group both the WAI ARIA W3C Recommendation and ARIA modules, namely:

Note: depending on the type of content being evaluated, part of the specifications might be irrelevant and should be ignored.

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.

Implementation Consistency Complete Report
Alfa Consistent Yes View Report
Axe-core Consistent Yes View Report
QualWeb Consistent Yes View Report
SortSite Consistent Yes View Report

Changelog

This is the first version of this ACT rule.

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This is an unpublished draft preview that might include content that is not yet approved. The published website is at w3.org/WAI/.