Checkliste

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. (Refer to Success Criterion 4.1.2 for additional requirements for controls and content that accepts user input.)
• Time-Based Media
  If non-text content is time-based media, then text alternatives at least provide descriptive identification of the non-text content. (Refer to Guideline 1.2 for additional requirements for media.)
• 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.

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.

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.

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.

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

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

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.

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

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

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.

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.

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.

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

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

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.

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

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

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.

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.

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.

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 Objects
  Parts of graphics required to understand the content, except when a particular presentation of graphics is essential to the information being conveyed.

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.

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.