Proposed Audio element content is media alternative for text
Description
This rule checks that the audio
element is a media alternative for text on the page.
Applicability
This rule applies to every non-streaming audio
element that is:
- playing; or,
- has a play button that is visible and included in the accessibility tree.
Expectation 1
The auditory information of each test target is available as text (directly or via text alternatives) that is visible and included in the accessibility tree.
Expectation 2
Each target element is labeled as an audio alternative for text on the page by content that is visible and included in the accessibility tree.
Assumptions
There are currently no assumptions
Accessibility Support
There are no major accessibility support issues known for this rule.
Background
Bibliography
Accessibility Requirements Mapping
This rule is not required for conformance.
Input Aspects
The following aspects are required in using this rule.
- DOM Tree
- CSS Styling
- Audio output (no link available)
- Language
Test Cases
Passed
Passed Example 1
This audio
element describes some of the text on the same page. The text on the page labels the audio as an alternative.
<html lang="en">
<p>
A part of a speech by John F. Kennedy: We choose to go to the moon in this decade and do the other things, not
because they are easy, but because they are hard, because that goal will serve to organize and measure the best of
our energies and skills, because that challenge is one that we are willing to accept, one we are unwilling to
postpone, and one which we intend to win, and the others, too.
</p>
<p>
You can also listen to the audio file below to hear the above part of the speech.
</p>
<audio src="/test-assets/moon-audio/moon-speech.mp3" controls></audio>
</html>
Failed
Failed Example 1
This audio
element describes some of the text on the same page. The audio contains more information than the text does.
<html lang="en">
<p>
A part of a speech by John F. Kennedy: We choose to go to the moon in this decade and do the other things, not
because they are easy, but because they are hard.
</p>
<p>
You can also listen to the audio file below to hear the above part of the speech.
</p>
<audio src="/test-assets/moon-audio/moon-speech.mp3" controls></audio>
</html>
Failed Example 2
This audio
element describes some of the text on the same page. The text is not visible on the page.
<html lang="en">
<p style="display: none;">
A part of a speech by John F. Kennedy: We choose to go to the moon in this decade and do the other things, not
because they are easy, but because they are hard, because that goal will serve to organize and measure the best of
our energies and skills, because that challenge is one that we are willing to accept, one we are unwilling to
postpone, and one which we intend to win, and the others, too.
</p>
<p>
You can also listen to the audio file below to hear the above part of the speech.
</p>
<audio src="/test-assets/moon-audio/moon-speech.mp3" controls></audio>
</html>
Failed Example 3
This audio
element describes some of the text on the same page. The text on the page does not label the audio as an alternative.
<html lang="en">
<p>
A part of a speech by John F. Kennedy: We choose to go to the moon in this decade and do the other things, not
because they are easy, but because they are hard, because that goal will serve to organize and measure the best of
our energies and skills, because that challenge is one that we are willing to accept, one we are unwilling to
postpone, and one which we intend to win, and the others, too.
</p>
<audio src="/test-assets/moon-audio/moon-speech.mp3" controls></audio>
</html>
Failed Example 4
This audio
element describes some of the text on the same page. The text on the page labels the audio as an alternative but the label is not visible on the page.
<html lang="en">
<p>
A part of a speech by John F. Kennedy: We choose to go to the moon in this decade and do the other things, not
because they are easy, but because they are hard, because that goal will serve to organize and measure the best of
our energies and skills, because that challenge is one that we are willing to accept, one we are unwilling to
postpone, and one which we intend to win, and the others, too.
</p>
<p style="display: none;">
You can also listen to the audio file below to hear the above part of the speech.
</p>
<audio src="/test-assets/moon-audio/moon-speech.mp3" controls></audio>
</html>
Inapplicable
Inapplicable Example 1
This audio
element describes some of the text on the same page. The text on the page labels the audio as an alternative but the controls are not visible on the page.
<html lang="en">
<p>
A part of a speech by John F. Kennedy: We choose to go to the moon in this decade and do the other things, not
because they are easy, but because they are hard, because that goal will serve to organize and measure the best of
our energies and skills, because that challenge is one that we are willing to accept, one we are unwilling to
postpone, and one which we intend to win, and the others, too.
</p>
<p>
You can also listen to the audio file below to hear the above part of the speech.
</p>
<audio src="/test-assets/moon-audio/moon-speech.mp3" controls style="display: none;"></audio>
</html>
Inapplicable Example 2
This audio
element describes some of the text on the same page. The text on the page labels the audio as an alternative but there are no controls.
<html lang="en">
<p>
A part of a speech by John F. Kennedy: We choose to go to the moon in this decade and do the other things, not
because they are easy, but because they are hard, because that goal will serve to organize and measure the best of
our energies and skills, because that challenge is one that we are willing to accept, one we are unwilling to
postpone, and one which we intend to win, and the others, too.
</p>
<p>
You can also listen to the audio file below to hear the above part of the speech.
</p>
<audio src="/test-assets/moon-audio/moon-speech.mp3"></audio>
</html>
Glossary
Focusable
An element is focusable if one or both of the following are true:
- the element is part of sequential focus navigation; or
- the element has a tabindex value that is not null.
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:
- The 1 second time span is an arbitrary limit which is not included in WCAG. Given that scripts can manage the focus state of elements, testing the focusability of an element consistently would be impractical without a time limit.
- The tabindex value of an element is the value of the tabindex attribute parsed using the rules for parsing integers. For the tabindex value to be different from null, it needs to be parsed without errors.
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.
Instrument to achieve an objective
An HTML element that when activated allows an end-user to achieve an objective.
Note: Any rule that uses this definition must provide an unambiguous description of the objective the instrument is used to achieve.
Non-streaming media element
A non-streaming media element is an HTML Media Element for which the duration
property is not 0.
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.
Play button
A play button is an instrument that when activated plays a media resource.
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:
- has a computed CSS property
display
ofnone
; or - has an
aria-hidden
attribute set totrue
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.
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.
For more details, see examples of visible.
Rule Versions
This is the first version of this ACT rule.
Implementations
There are currently no known implementations for this rule. If you would like to contribute an implementation, please read the ACT Implementations page for details.