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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 for which all the following are true:

Expectation

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

Assumptions

There are currently no assumptions

Accessibility Support

Some screen readers announce object elements even if they do not have an accessible name, while other skip the element. If an object is used to render decorative content, to ensure it is marked as decorative and can be ignored by all major screen readers a presentational role is necessary.

The MIME type of the resource embedded in the data attribute impacts how the accessible name of the object is computed. For example, object embedding image MIME type may use their alt attribute to compute their accessible name, but object embedding audio or video MIME types may not. An object does not officially support the use of an alt so this may behave differently according to the browser used.

Background

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

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

Object elements without an accessible name are ignored by assistive technologies unless they have an explicit role.

When the object resource is not loaded, the fallback content is rendered as shown in the Inapplicable Example: “This object element does not need an accessible name because it loads no image, audio, or video.”

Bibliography

Accessibility Requirements Mapping

Input Aspects

The following aspects are required in using this rule.

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 logo</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 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>

Failed Example 2

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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 3

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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 4

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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 5

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This object element has an empty accessible name. The img element inside the object is not used in computing the object’s accessible name.

<object data="/test-assets/shared/w3c-logo.png">
	<img src="/test-assets/shared/w3c-logo.png" alt="W3C logo" />
</object>

Failed Example 6

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This object element has alt attribute, however this will not create an accessible name. Because of this the accessible name is empty.

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

Inapplicable

Inapplicable Example 1

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This object element has an explicit role of “img”.

Note: Object elements with other roles may still require an accessible name. This is tested through other rules.

<object role="img" title="W3C" data="/test-assets/shared/w3c-logo.png"></object>

Inapplicable Example 2

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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 3

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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 4

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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 5

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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 6

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This object element embeds an HTML resource.

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

Inapplicable Example 7

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There is no object element.

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

Inapplicable Example 8

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This object element does not need an accessible name because it loads no image, audio, or video. Instead the img element inside the object is rendered.

<object data="/invalid/url/index.html">
	<img src="/test-assets/shared/w3c-logo.png" alt="W3C logo" />
</object>

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

An element is focusable if one or both of the following are true:

Exception: Elements that lose focus during a period of up to 1 second after gaining focus, without the user interacting with the page the element is on, are not considered focusable.

Notes:

Included in the accessibility tree

Elements included in the accessibility tree of platform specific accessibility APIs are exposed to assistive technologies. This allows users of assistive technology to access the elements in a way that meets 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.

Programmatically hidden elements are removed from the accessibility tree. However, some browsers will leave focusable elements with an aria-hidden attribute set to true in the accessibility tree. Because they are hidden, these elements are considered not included in the accessibility tree. This may cause confusion for users of assistive technologies because they may still be able to interact with these focusable elements using sequential keyboard navigation, even though the element should not be 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 they are programmatically hidden. This is different from marking the element as decorative and does not convey the same intention. Notably, being programmatically hidden 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.

Programmatically Hidden

An HTML element is programmatically hidden if either it has a computed CSS property visibility whose value is not visible; or at least one of the following is true for any of its inclusive ancestors in the flat tree:

Note: Contrary to the other conditions, the visibility CSS property may be reverted by descendants.

Note: The HTML standard suggests setting the CSS display property to none for elements with the hidden attribute. While not required by HTML, all modern browsers follow this suggestion. Because of this the hidden attribute is not used in this definition. In browsers that use this suggestion, overriding the CSS display property can reveal elements with the hidden attribute.

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.

Rule Versions

  1. Latest version, 31 August 2023 (compare)
    • Update to reference ARIA 1.2
  2. Previous version, 25 October 2022
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