The Web Content Accessibility Guidelines 2.0

1.1.1

Non-text Content: 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. (Level A)

• 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. (Refer to Guideline 1.2 for additional requirements for media.)
• Tests: If non-text content is a test, exercise or game 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.
• 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.

1.3.1

Info and Relationships: Information, structure, and relationships conveyed through presentation can be programmatically determined or are available in text. (Level A)

1.4.4

Resize text: Except for captions and images of text, text can be resized without assistive technology up to 200 percent without loss of content or functionality. (Level AA)

1.4.5

Images of Text: 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: (Level AA)

• 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.

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

2.1.1

Keyboard: All functionality of the content is operable through a keyboard interface without requiring specific timings for individual keystrokes, except where the underlying function requires input that depends on the path of the user’s movement and not just the endpoints. (Level A)

Note 1: This exception relates to the underlying function, not the input technique. For example, if using handwriting to enter text, the input technique (handwriting) requires path-dependent input but the underlying function (text input) does not.

Note 2: This does not forbid and should not discourage providing mouse input or other input methods in addition to keyboard operation.

2.1.2

No Keyboard Trap: If keyboard focus can be moved to a component of the page using a keyboard interface, then focus can be moved away from that component using only a keyboard interface, and, if it requires more than unmodified arrow or tab keys or other standard exit methods, the user is advised of the method for moving focus away. (Level A)

Note: 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 it is used to meet other success criteria or not) must meet this success criterion. See Conformance Requirement 5: Non-Interference.

2.2.1

Timing Adjustable: For each time limit that is set by the content, at least one of the following is true: (Level A)

• Turn off: The user is allowed to turn off the time limit before encountering it; or
• Adjust: The user is allowed to adjust the time limit before encountering it over a wide range that is at least ten times the length of the default setting; or
• Extend: The user is warned before time expires and given at least 20 seconds to extend the time limit with a simple action (for example, “press the space bar”), and the user is allowed to extend the time limit at least ten times; or
• Real-time Exception: The time limit is a required part of a real-time event (for example, an auction), and no alternative to the time limit is possible; or
• Essential Exception: The time limit is essentialand extending it would invalidate the activity; or
• 20 Hour Exception: The time limit is longer than 20 hours.

Note: This success criterion helps ensure that users can complete tasks without unexpected changes in content or context that are a result of a time limit. This success criterion should be considered in conjunction with Success Criterion 3.2.1, which puts limits on changes of content or context as a result of user action.

2.2.2

Pause, Stop, Hide: For moving, blinking, scrolling, or auto-updating information, all of the following are true: (Level A)

• Moving, blinking, scrolling: For any moving, blinking or scrolling information that (1) starts automatically, (2) lasts more than five seconds, and (3) is presented in parallel with other content, there is a mechanism for the user to pause, stop, or hide it unless the movement, blinking, or scrolling is part of an activity where it is essential; and
• Auto-updating: For any auto-updating information that (1) starts automatically and (2) is presented in parallel with other content, there is a mechanism for the user to pause, stop, or hide it or to control the frequency of the update unless the auto-updating is part of an activity where it is essential.

Note: Content that is updated periodically by software or that is streamed to the user agent is not required to preserve or present information that is generated or received between the initiation of the pause and resuming presentation, as this may not be technically possible, and in many situations could be misleading to do so.

Note: An animation that occurs as part of a preload phase or similar situation can be considered essential if interaction cannot occur during that phase for all users and if not indicating progress could confuse users or cause them to think that content was frozen or broken.

2.3.1

Three Flashes or Below Threshold: Web pages do not contain anything that flashes more than three times in any one second period, or the flash is below the general flash and red flash thresholds. (Level A)

Note: 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 it is used to meet other success criteria or not) must meet this success criterion.

2.4.3

Focus Order: If a Web page can be navigated sequentially and the navigation sequences affect meaning or operation, focusable components receive focus in an order that preserves meaning and operability. (Level A)

2.4.5

Multiple Ways: More than one way is available to locate a Web page within a set of Web pages except where the Web Page is the result of, or a step in, a process. (Level AA)

2.4.7

Focus Visible: Any keyboard operable user interface has a mode of operation where the keyboard focus indicator is visible. (Level AA)

3.1.1

Language of Page: The default human language of each Web page can be programmatically determined. (Level A)

3.2.4

Consistent Identification: Components that have the same functionality within a set of Web pages are identified consistently. (Level AA)

4.1.1

4.1.1 Parsing: In content implemented using markup languages, elements have complete start and end tags, elements are nested according to their specifications, elements do not contain duplicate attributes, and any IDs are unique, except where the specifications allow these features. (Level A)

Note: Start and end tags that are missing a critical character in their formation, such as a closing angle bracket or a mismatched attribute value quotation mark are not complete.

1.1.1

• G94: Providing short text alternative for non-text content that serves the same purpose and presents the same information as the non-text content

• G95: Providing short text alternatives that provide a brief description of the non-text content AND one of the following techniques for long description:
  • G74: Providing a long description in text near the non-text content, with a reference to the location of the long description in the short description
  • G73: Providing a long description in another location with a link to it that is immediately adjacent to the non-text content

• G82: Providing a short text alternative that identifies the purpose of the non-text content

• G68: Providing a descriptive short text alternative that describes the purpose of live audio-only and live video-only content
• G100: Providing a short text alternative which is the accepted name or a descriptive name of the non-text content

1.3.1

• G115: Using semantic elements to mark up structure AND H49: Using semantic markup to mark emphasized or special text (HTML)
• G117: Using text to convey information that is conveyed by variations in presentation of text
• G140: Separating information and structure from presentation to enable different presentations
• Making information and relationships conveyed through presentation programmatically determinable using the following techniques:
  • G138: Using semantic markup whenever color cues are used
  • H48: Using ol, ul and dl for lists or groups of links (HTML)

• G117: Using text to convey information that is conveyed by variations in presentation of text

1.4.4

• G142: Using a technology that has commonly-available user agents that support zoom
• Ensuring that text containers resize when the text resizes AND using measurements that are relative to other measurements in the content by using one or more of the following techniques:
• C28: Specifying the size of text containers using em units (CSS)
• Techniques for relative measurements
  • C12: Using percent for font sizes (CSS)
  • C13: Using named font sizes (CSS)
  • C14: Using em units for font sizes (CSS)
• Techniques for text container resizing
  • G146: Using liquid layout
• G178: Providing controls on the Web page that allow users to incrementally change the size of all text on the page up to 200 percent
• G179: Ensuring that there is no loss of content or functionality when the text resizes and text containers do not change their width

1.4.5

• C22: Using CSS to control visual presentation of text (CSS)
• C30: Using CSS to replace text with images of text and providing user interface controls to switch (CSS)
  • G140: Separating information and structure from presentation to enable different presentations

2.1.1

• G202: Ensuring keyboard control for all functionality
  • H91: Using HTML form controls and links (HTML)
  • G90: Providing keyboard-triggered event handlers

2.1.2

• G21: Ensuring that users are not trapped in content

2.2.1

Situation A: If there are session time limits:

• G133: Providing a checkbox on the first page of a multipart form that allows users to ask for longer session time limit or no session time limit
• G198: Providing a way for the user to turn the time limit off

Situation B: If a time limit is controlled by a script on the page:

• G198: Providing a way for the user to turn the time limit off
• G180: Providing the user with a means to set the time limit to 10 times the default time limit

Situation C: If there are time limits on reading:

• G4: Allowing the content to be paused and restarted from where it was paused
• G198: Providing a way for the user to turn the time limit off

2.2.2

• G4: Allowing the content to be paused and restarted from where it was paused
• G11: Creating content that blinks for less than 5 seconds
• G187: Using a technology to include blinking content that can be turned off via the user agent
• G152: Setting animated gif images to stop blinking after n cycles (within 5 seconds)
• G186: Using a control in the Web page that stops moving, blinking, or auto-updating content
• G191: Providing a link, button, or other mechanism that reloads the page without any blinking content

2.3.1

• G19: Ensuring that no component of the content flashes more than three times in any 1-second period
• G176: Keeping the flashing area small enough
• G15: Using a tool to ensure that content does not violate the general flash threshold or red flash threshold

2.4.3

• G59: Placing the interactive elements in an order that follows sequences and relationships within the content
• Giving focus to elements in an order that follows sequences and relationships within the content using one of the following techniques:
• H4: Creating a logical tab order through links, form controls, and objects (HTML)
• C27: Making the DOM order match the visual order (CSS)

2.4.5

Using two or more of the following techniques:

• G125: Providing links to navigate to related Web pages
• G64: Providing a Table of Contents
• G63: Providing a site map
• G161: Providing a search function to help users find content
• G126: Providing a list of links to all other Web pages
• G185: Linking to all of the pages on the site from the home page

2.4.7

• G149: Using user interface components that are highlighted by the user agent when they receive focus
• C15: Using CSS to change the presentation of a user interface component when it receives focus (CSS)
• G165: Using the default focus indicator for the platform so that high visibility default focus indicators will carry over
• G195: Using an author-supplied, highly visible focus indicator

3.1.1

• H57: Using language attributes on the html element (HTML)

3.2.4

• G197: Using labels, names, and text alternatives consistently for content that has the same functionality AND following the sufficient techniques for Success Criterion 1.1.1 AND sufficient techniques for Success Criterion 4.1.2 for providing labels, names, and text alternatives.

4.1.1

• G134: Validating Web pages
• G192: Fully conforming to specifications
• H88: Using HTML according to spec (HTML)
• Ensuring that Web pages can be parsed by using one of the following techniques:
• H74: Ensuring that opening and closing tags are used according to specification (HTML) AND H93: Ensuring that id attributes are unique on a Web page (HTML) AND H94: Ensuring that elements do not contain duplicate attributes (HTML)
• H75: Ensuring that Web pages are well-formed (HTML)

F30

F20

F67

F2

F17

F42

F43

F68

F69

F80

F54

F55

F42

F10

F40

F41

F58

F16

F47

F4

F50

F7

F44

F55

F78

F31

F70

F77

F17

F62