👁️Perceivable

Perceivable 🔈

Information and interface elements must be presentable to users in ways they can perceive:

• Provide text alternatives for non-text content 🖼️

• Provide captions and transcripts for audiovisuals 🎥

• Create content that can be presented in different ways ↔️

• Make it easier to see and hear content 🔊👀

Text Alternatives

Provide text alternatives for any non-text content so that it can be changed into other forms people need, such as large print, braille, speech, symbols or simpler language.

Success Criterion 1.1.1 Non-text Content

(Level A)

All non-text content that is presented to the user has a text alternative that serves the equivalent purpose, except for the situations listed below.

Controls, Input

If non-text content is a control or accepts user input, then it has a name that describes its purpose.

Time-Based Media

If non-text content is time-based media, then text alternatives at least provide descriptive identification of the non-text content.

Test

If non-text content is a test or exercise that would be invalid if presented in text, then text alternatives at least provide descriptive identification of the non-text content.

Sensory

If non-text content is primarily intended to create a specific sensory experience, then text alternatives at least provide descriptive identification of the non-text content.

CAPTCHA

If the purpose of non-text content is to confirm that content is being accessed by a person rather than a computer, then text alternatives that identify and describe the purpose of the non-text content are provided, and alternative forms of CAPTCHA using output modes for different types of sensory perception are provided to accommodate different disabilities.

Decoration, Formatting, Invisible

If non-text content is pure decoration, is used only for visual formatting, or is not presented to users, then it is implemented in a way that it can be ignored by assistive technology.

Time-based Media

Provide alternatives for time-based media.

Success Criterion 1.2.1 Audio-only and Video-only (Prerecorded)

(Level A)

For prerecorded audio-only and prerecorded video-only media, the following are true, except when the audio or video is a media alternative for text and is clearly labeled as such:

Prerecorded Audio-only

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

Prerecorded Video-only

Either an alternative for time-based media or an audio track is provided that presents equivalent information for prerecorded video-only content.

Success Criterion 1.2.2 Captions (Prerecorded)

(Level A)

Captions are provided for all prerecorded audio content in synchronized media, except when the media is a media alternative for text and is clearly labeled as such.

Success Criterion 1.2.3 Audio Description or Media Alternative (Prerecorded)

(Level A)

An alternative for time-based media or audio description of the prerecorded video content is provided for synchronized media, except when the media is a media alternative for text and is clearly labeled as such.

Success Criterion 1.2.4 Captions (Live)

(Level AA)

Captions are provided for all live audio content in synchronized media.

Success Criterion 1.2.5 Audio Description (Prerecorded)

(Level AA)

Audio description is provided for all prerecorded video content in synchronized media.

Success Criterion 1.2.6 Sign Language (Prerecorded)

(Level AAA)

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

Success Criterion 1.2.7 Extended Audio Description (Prerecorded)

(Level AAA)

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.

Success Criterion 1.2.8 Media Alternative (Prerecorded)

(Level AAA)

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

Success Criterion 1.2.9 Audio-only (Live)

(Level AAA)

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

Adaptable

Create content that can be presented in different ways (for example simpler layout) without losing information or structure.

Success Criterion 1.3.1 Info and Relationships

(Level A)

Information, structure, and relationships conveyed through presentation can be programmatically determined or are available in text.

Success Criterion 1.3.2 Meaningful Sequence

(Level A)

When the sequence in which content is presented affects its meaning, a correct reading sequence can be programmatically determined.

Success Criterion 1.3.3 Sensory Characteristics

(Level A)

Instructions provided for understanding and operating content do not rely solely on sensory characteristics of components such as shape, color, size, visual location, orientation, or sound.

Note

For requirements related to color, refer to Guideline 1.4.

Success Criterion 1.3.4 Orientation

(Level AA)

Content does not restrict its view and operation to a single display orientation, such as portrait or landscape, unless a specific display orientation is essential.

Note

Examples where a particular display orientation may be essential are a bank check, a piano application, slides for a projector or television, or virtual reality content where binary display orientation is not applicable.

Success Criterion 1.3.5 Identify Input Purpose

(Level AA)

The purpose of each input field collecting information about the user can be programmatically determined when:

• The input field serves a purpose identified in the Input Purposes for User Interface Components section; and

• The content is implemented using technologies with support for identifying the expected meaning for form input data.

Success Criterion 1.3.6 Identify Purpose

(Level AAA)

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

Distinguishable

Make it easier for users to see and hear content including separating foreground from background.

Success Criterion 1.4.1 Use of Color

(Level A)

Color is not used as the only visual means of conveying information, indicating an action, prompting a response, or distinguishing a visual element.

This success criterion addresses color perception specifically.

Success Criterion 1.4.2 Audio Control

(Level A)

If any audio on a Web page plays automatically for more than 3 seconds, either a mechanism is available to pause or stop the audio, or a mechanism is available to control audio volume independently from the overall system volume level.

Since any content that does not meet this success criterion can interfere with a user's ability to use the whole page, all content on the Web page (whether or not it is used to meet other success criteria) must meet this success criterion.

Success Criterion 1.4.3 Contrast (Minimum)

(Level AA)

The visual presentation of text and images of text has a contrast ratio of at least 4.5:1, except for the following:

Large Text

Large-scale text and images of large-scale text have a contrast ratio of at least 3:1;

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.

Logo types

Text that is part of a logo or brand name has no contrast requirement.

Success Criterion 1.4.4 Resize text

(Level AA)

Except for captions and images of text, text can be resized without assistive technology up to 200 percent without loss of content or functionality.

Success Criterion 1.4.5 Images of Text

(Level AA)

If the technologies being used can achieve the visual presentation, text is used to convey information rather than images of text except for the following:

Customizable

The image of text can be visually customized to the user's requirements;

Essential

A particular presentation of text is essential to the information being conveyed.

Logotypes (text that is part of a logo or brand name) are considered essential.

Success Criterion 1.4.6 Contrast (Enhanced)

(Level AAA)

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.

Success Criterion 1.4.7 Low or No Background Audio

(Level AAA)

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.

Per the definition of "decibel," background sound that meets this requirement will be approximately four times quieter than the foreground speech content.

Success Criterion 1.4.8 Visual Presentation

(Level AAA)

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.

Success Criterion 1.4.9 Images of Text (No Exception)

(Level AAA)

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

Logotypes (text that is part of a logo or brand name) are considered essential.

Success Criterion 1.4.10 Reflow

(Level AA)

Content can be presented without loss of information or functionality, and without requiring scrolling in two dimensions for:

• Vertical scrolling content at a width equivalent to 320 CSS pixels;

• Horizontal scrolling content at a height equivalent to 256 CSS pixels.

Except for parts of the content which require two-dimensional layout for usage or meaning.

Note: 320 CSS pixels is equivalent to a starting viewport width of 1280 CSS pixels wide at 400% zoom. For web content which are designed to scroll horizontally (e.g. with vertical text), the 256 CSS pixels is equivalent to a starting viewport height of 1024px at 400% zoom.

Examples of content which require two-dimensional layout are images, maps, diagrams, video, games, presentations, data tables, and interfaces where it is necessary to keep toolbars in view while manipulating content.

Success Criterion 1.4.11 Non-text Contrast

(Level AA)

The visual presentation of the following have a contrast ratio of at least 3:1 against adjacent color(s):

User Interface Components

Visual information required to identify user interface components and states, except for inactive components or where the appearance of the component is determined by the user agent and not modified by the author;Graphical ObjectsParts of graphics required to understand the content, except when a particular presentation of graphics is essential to the information being conveyed.

Success Criterion 1.4.12 Text Spacing

(Level AA)

In content implemented using markup languages that support the following text style properties, no loss of content or functionality occurs by setting all of the following and by changing no other style property:

• Line height (line spacing) to at least 1.5 times the font size;

• Spacing following paragraphs to at least 2 times the font size;

• Letter spacing (tracking) to at least 0.12 times the font size;

• Word spacing to at least 0.16 times the font size.

Exception: Human languages and scripts that do not make use of one or more of these text style properties in written text can conform using only the properties that exist for that combination of language and script.

Success Criterion 1.4.13 Content on Hover or Focus

(Level AA)

Where receiving and then removing pointer hover or keyboard focus triggers additional content to become visible and then hidden, the following are true:

Dismissable

A mechanism is available to dismiss the additional content without moving pointer hover or keyboard focus, unless the additional content communicates an input error or does not obscure or replace other content;

Hoverable

If pointer hover can trigger the additional content, then the pointer can be moved over the additional content without the additional content disappearing;

Persistent

The additional content remains visible until the hover or focus trigger is removed, the user dismisses it, or its information is no longer valid.

Exception: The visual presentation of the additional content is controlled by the user agent and is not modified by the author.