Perspectives

PERCEIVABLE

Sign language interpretation is provided for all prerecorded audio content in synchronized media.

Where pauses in foreground audio are insufficient to allow audio descriptions to convey the sense of the video, extended audio description is provided for all prerecorded video content in synchronized media.

An alternative for time-based media is provided for all prerecorded synchronized media and for all prerecorded video-only media.

An alternative for time-based media that presents equivalent information for live audio-only content is provided.

In content implemented using markup languages, the purpose of User Interface Components, icons, and regions can be programmatically determined.

The visual presentation of text and images of text has a contrast ratio of at least 7:1, except for the following:

Large Text
Large-scale text and images of large-scale text have a contrast ratio of at least 4.5:1;
Incidental
Text or images of text that are part of an inactive user interface component, that are pure decoration, that are not visible to anyone, or that are part of a picture that contains significant other visual content, have no contrast requirement.
Logotypes
Text that is part of a logo or brand name has no contrast requirement.

For prerecorded audio-only content that (1) contains primarily speech in the foreground, (2) is not an audio CAPTCHA or audio logo, and (3) is not vocalization intended to be primarily musical expression such as singing or rapping, at least one of the following is true:

No Background
The audio does not contain background sounds.
Turn Off
The background sounds can be turned off.
20 dB
The background sounds are at least 20 decibels lower than the foreground speech content, with the exception of occasional sounds that last for only one or two seconds.

For the visual presentation of blocks of text, a mechanism is available to achieve the following:

Foreground and background colors can be selected by the user.
Width is no more than 80 characters or glyphs (40 if CJK).
Text is not justified (aligned to both the left and the right margins).
Line spacing (leading) is at least space-and-a-half within paragraphs, and paragraph spacing is at least 1.5 times larger than the line spacing.
Text can be resized without assistive technology up to 200 percent in a way that does not require the user to scroll horizontally to read a line of text on a full-screen window.

Images of text are only used for pure decoration or where a particular presentation of text is essential to the information being conveyed.

OPERABLE

Timing is not an essential part of the event or activity presented by the content, except for non-interactive synchronized media and real-time events.

Interruptions can be postponed or suppressed by the user, except interruptions involving an emergency.

When an authenticated session expires, the user can continue the activity without loss of data after re-authenticating.

Users are warned of the duration of any user inactivity that could cause data loss, unless the data is preserved for more than 20 hours when the user does not take any actions.

Information about the user's location within a set of Web pages is available.

A mechanism is available to allow the purpose of each link to be identified from link text alone, except where the purpose of the link would be ambiguous to users in general.

Section headings are used to organize the content.

The size of the target for pointer inputs is at least 44 by 44 CSS pixels except when:

Equivalent
The target is available through an equivalent link or control on the same page that is at least 44 by 44 CSS pixels;
Inline
The target is in a sentence or block of text;
User Agent Control
The size of the target is determined by the user agent and is not modified by the author;
Essential
A particular presentation of the target is essential to the information being conveyed.

Web content does not restrict use of input modalities available on a platform except where the restriction is essential, required to ensure the security of the content, or required to respect user settings.

UNDERSTANDABLE

A mechanism is available for identifying specific definitions of words or phrases used in an unusual or restricted way, including idioms and jargon.

A mechanism for identifying the expanded form or meaning of abbreviations is available.

When text requires reading ability more advanced than the lower secondary education level after removal of proper names and titles, supplemental content, or a version that does not require reading ability more advanced than the lower secondary education level, is available.

A mechanism is available for identifying specific pronunciation of words where meaning of the words, in context, is ambiguous without knowing the pronunciation.

Changes of context are initiated only by user request or a mechanism is available to turn off such changes.

Context-sensitive help is available.

For Web pages that require the user to submit information, at least one of the following is true:

Reversible
Submissions are reversible.
Checked
Data entered by the user is checked for input errors and the user is provided an opportunity to correct them.
Confirmed
A mechanism is available for reviewing, confirming, and correcting information before finalizing the submission.