This principle ensures that users can perceive the information being presented.
Ensure all non-text content on a webpage is accompanied by a text alternative that conveys equivalent information, making it accessible to users with disabilities. This includes images, charts, videos, and other multimedia elements.
Provide alternatives for audio-only and video-only content by supplying transcripts and text descriptions.
Captions are provided for all prerecorded audio content in synchronized media to make it accessible to users with hearing impairments.
An alternative for time-based media or audio description of the prerecorded video content is provided.
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.
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, 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.
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 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 customizations.
The visual presentation of text and images of text has a contrast ratio of at least 7:1.
For prerecorded audio-only content that contains primarily speech in the foreground, at least one of the following is true: No background sounds are present, background sounds can be turned off, or background sounds are at least 20 decibels lower than the foreground speech content.
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, text is not justified, line spacing is at least 1.5 spaces within paragraphs and paragraph spacing is at least 1.5 times larger than the line spacing, and text can be resized without assistive technology up to 200 percent without loss of content or functionality.
Images of text are only used for pure decoration or where a particular presentation of text is essential.
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, and horizontal scrolling content at a height equivalent to 256 CSS pixels.
The visual presentation of the following have a contrast ratio of at least 3:1 against adjacent color(s): User interface components and graphical objects.
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, and word spacing to at least 0.16 times the font size.
Where receiving and then removing pointer hover or keyboard focus triggers additional content to become visible and then hidden, the following are true: Dismissable, hoverable, and persistent.
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 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 customizations.