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上海时时乐走势分析图:Comparison of WCAG 1.0 Checkpoints to WCAG 2.0, in Numerical Order

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This page shows how the WCAG 1.0 checkpoints relate to WCAG 2.0, which was published 11 December 2008.

WAI is working carefully to enable organizations and individuals who are currently using WCAG 1.0 to make a smooth transition to WCAG 2.0. Additional resources will be announced on the WAI home page, WAI RSS feed, and public WAI IG email list.

New WCAG 2.0 requirements not mentioned in the comparison table below

Listing by Checkpoint

WCAG 1.0WCAG 2.0

1.1: Provide a text equivalent for every non-text element (e.g., via "alt", "longdesc", or in element content). This includes: images, graphical representations of text (including symbols), image map regions, animations (e.g., animated GIFs), applets and programmatic objects, ascii art, frames, scripts, images used as list bullets, spacers, graphical buttons, sounds (played with or without user interaction), stand-alone audio files, audio tracks of video, and video. [Priority 1]

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. (Refer to Guideline 4.1 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.

1.2.1 Audio-only and Video-only (Prerecorded): 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: (Level A)

  • 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.

1.2.9 Audio-only (Live): An alternative for time-based media that presents equivalent information for live audio-only content is provided. (Level AAA)


Additional Notes:

1.2: Provide redundant text links for each active region of a server-side image map. [Priority 1]

With regard to text alternatives:

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. (Refer to Guideline 4.1 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.

With regard to keyboard access:

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.

2.4.4 Link Purpose (In Context): The purpose of each link can be determined from the link text alone or from the link text together with its programmatically determined link context, except where the purpose of the link would be ambiguous to users in general. (Level A)


Additional Notes:

  • Server-side image maps are not keyboard accessible.

1.3: Until user agents can automatically read aloud the text equivalent of a visual track, provide an auditory description of the important information of the visual track of a multimedia presentation. [Priority 1]

1.2.3 Audio Description or Media Alternative (Prerecorded): 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. (Level A)

1.2.5 Audio Description (Prerecorded): Audio description is provided for all prerecorded video content in synchronized media. (Level AA)

1.2.7 Extended Audio Description (Prerecorded): 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. (Level AAA)

1.4: For any time-based multimedia presentation (e.g., a movie or animation), synchronize equivalent alternatives (e.g., captions or auditory descriptions of the visual track) with the presentation. [Priority 1]

1.2.2 Captions (Prerecorded): 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. (Level A)

1.2.3 Audio Description or Media Alternative (Prerecorded): 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. (Level A)

1.2.4 Captions (Live): Captions are provided for all live audio content in synchronized media. (Level AA)

1.2.5 Audio Description (Prerecorded): Audio description is provided for all prerecorded video content in synchronized media. (Level AA)

1.2.7 Extended Audio Description (Prerecorded): 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. (Level AAA)

1.5: Until user agents render text equivalents for client-side image map links, provide redundant text links for each active region of a client-side image map. [Priority 3]

This is no longer required because user agents now render text alternatives for client-side image map areas.

2.1: Ensure that all information conveyed with color is also available without color, for example from context or markup. [Priority 1]

1.4.1 Use of Color: Color is not used as the only visual means of conveying information, indicating an action, prompting a response, or distinguishing a visual element. (Level A)

Note: This success criterion addresses color perception specifically. Other forms of perception are covered in Guideline 1.3 including programmatic access to color and other visual presentation coding.

2.2: Ensure that foreground and background color combinations provide sufficient contrast when viewed by someone having color deficits or when viewed on a black and white screen. [Priority 2 for images, Priority 3 for text].

1.4.3 Contrast (Minimum): The visual presentation of text and images of text has a contrast ratio of at least 4.5:1, except for the following: (Level AA)

  • 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 minimum contrast requirement.

1.4.6 Contrast (Enhanced): The visual presentation of text and images of text has a contrast ratio of at least 7:1, except for the following: (Level AAA)

  • 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 minimum contrast requirement.

3.1: When an appropriate markup language exists, use markup rather than images to convey information. [Priority 2]

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.

1.4.9 Images of Text (No Exception): Images of text are only used for pure decoration or where a particular presentation of text is essential to the information being conveyed. (Level AAA)

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

Conformance Requirement 4: Only Accessibility-Supported Ways of Using Technologies: Only accessibility-supported ways of using technologies are relied upon to satisfy the success criteria. Any information or functionality that is provided in a way that is not accessibility supported is also available in a way that is accessibility supported. (See Understanding accessibility support.) Understanding Conformance Requirement 4

3.2: Create documents that validate to published formal grammars. [Priority 2]

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.


Additional Notes:

  • Validating to published formal grammars is a stronger requirement than what is required by Success Criterion 4.1.1 but validation is one of the sufficient techniques for this Success Criterion. Refer to Understanding Success Criterion 4.1.1

3.3: Use style sheets to control layout and presentation. [Priority 2]

This checkpoint maps to several sufficient and advisory techniques related to Success Criterion 1.3.1 (Level A), Success Criterion 1.3.2 (Level A), Success Criterion 1.4.1 (Level A), Success Criterion 1.4.4 (Level AA), Success Criterion 1.4.5 (Level AA), Success Criterion 2.4.7 (Level AA), Success Criterion 1.4.8 (Level AAA), and Success Criterion 1.4.9 (Level AAA). There is no direct mapping.

3.4: Use relative rather than absolute units in markup language attribute values and style sheet property values. [Priority 2]

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)


Additional Notes:

3.5 Use header elements to convey document structure and use them according to specification. [Priority 2]

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

2.4.10 Section Headings: Section headings are used to organize the content. (Level AAA)

Note 1: "Heading" is used in its general sense and includes titles and other ways to add a heading to different types of content.

Note 2: This success criterion covers sections within writing, not user interface components. User Interface components are covered under Success Criterion 4.1.2.

3.6: Mark up lists and list items properly. [Priority 2]

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

Specifically:

3.7: Mark up quotations. Do not use quotation markup for formatting effects such as indentation. [Priority 2]

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

Specifically:

4.1: Clearly identify changes in the natural language of a document's text and any text equivalents (e.g., captions). [Priority 1]

3.1.2 Language of Parts: The human language of each passage or phrase in the content can be programmatically determined except for proper names, technical terms, words of indeterminate language, and words or phrases that have become part of the vernacular of the immediately surrounding text. (Level AA)

4.2: Specify the expansion of each abbreviation or acronym in a document where it first occurs. [Priority 3]

3.1.4 Abbreviations: A mechanism for identifying the expanded form or meaning of abbreviations is available. (Level AAA)

4.3: Identify the primary natural language of a document. [Priority 3]

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

5.1: For data tables, identify row and column headers. [Priority 1]

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

Specifically:

5.2: For data tables that have two or more logical levels of row or column headers, use markup to associate data cells and header cells. [Priority 1]

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

Specifically:

5.3: Do not use tables for layout unless the table makes sense when linearized. Otherwise, if the table does not make sense, provide an alternative equivalent (which may be a linearized version). [Priority 2]

1.3.2 Meaningful Sequence: When the sequence in which content is presented affects its meaning, a correct reading sequence can be programmatically determined. (Level A)

5.4: If a table is used for layout, do not use any structural markup for the purpose of visual formatting. [Priority 2]

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

Specifically: F43: Failure of Success Criterion 1.3.1 due to using structural markup in a way that does not represent relationships in the content.

5.5: Provide summaries for tables. [Priority 3]

This is no longer required for conformance. However, in layout tables, the summary attribute must be omitted or empty. See F43: Failure of Success Criterion 1.3.1 due to using structural markup in a way that does not represent relationships in the content.

5.6: Provide abbreviations for header labels. [Priority 3]

This is no longer required for conformance, but is a potentially useful technique.

6.1: Organize documents so they may be read without style sheets. For example, when an HTML document is rendered without associated style sheets, it must still be possible to read the document. [Priority 1]

Conformance Requirement 4: Only Accessibility-Supported Ways of Using Technologies: Only accessibility-supported ways of using technologies are relied upon to satisfy the success criteria. Any information or functionality that is provided in a way that is not accessibility supported is also available in a way that is accessibility supported. (See Understanding accessibility support.) Understanding Conformance Requirement 4

Conformance Requirement 5: Non-Interference: If technologies are used in a way that is not accessibility supported, or if they are used in a non-conforming way, then they do not block the ability of users to access the rest of the page. In addition, the Web page as a whole continues to meet the conformance requirements under each of the following conditions: Understanding Conformance Requirement 5

  1. when any technology that is not relied upon is turned on in a user agent,

  2. when any technology that is not relied upon is turned off in a user agent, and

  3. when any technology that is not relied upon is not supported by a user agent

In addition, the following success criteria apply to all content on the page, including content that is not otherwise relied upon to meet conformance, because failure to meet them could interfere with any use of the page:

  • 1.4.2 - Audio Control,

  • 2.1.2 - No Keyboard Trap,

  • 2.3.1 - Three Flashes or Below Threshold, and

  • 2.2.2 - Pause, Stop, Hide.

6.2: Ensure that equivalents for dynamic content are updated when the dynamic content changes. [Priority 1]

F20: Failure of Success Criterion 1.1.1 and 4.1.2 due to not updating text alternatives when changes to non-text content occur

Additional Notes:

6.3: Ensure that pages are usable when scripts, applets, or other programmatic objects are turned off or not supported. If this is not possible, provide equivalent information on an alternative accessible page. [Priority 1]

Conformance Requirement 1: Conformance Level: One of the following levels of conformance is met in full. Understanding Conformance Requirement 1

  • Level A: For Level A conformance (the minimum level of conformance), the Web page satisfies all the Level A Success Criteria, or a conforming alternate version is provided.

  • Level AA: For Level AA conformance, the Web page satisfies all the Level A and Level AA Success Criteria, or a Level AA conforming alternate version is provided.

  • Level AAA: For Level AAA conformance, the Web page satisfies all the Level A, Level AA and Level AAA Success Criteria, or a Level AAA conforming alternate version is provided.

Note 1: Although conformance can only be achieved at the stated levels, authors are encouraged to report (in their claim) any progress toward meeting success criteria from all levels beyond the achieved level of conformance.

Note 2: It is not recommended that Level AAA conformance be required as a general policy for entire sites because it is not possible to satisfy all Level AAA Success Criteria for some content.

Conformance Requirement 4: Only Accessibility-Supported Ways of Using Technologies: Only accessibility-supported ways of using technologies are relied upon to satisfy the success criteria. Any information or functionality that is provided in a way that is not accessibility supported is also available in a way that is accessibility supported. (See Understanding accessibility support.) Understanding Conformance Requirement 4

Conformance Requirement 5: Non-Interference: If technologies are used in a way that is not accessibility supported, or if they are used in a non-conforming way, then they do not block the ability of users to access the rest of the page. In addition, the Web page as a whole continues to meet the conformance requirements under each of the following conditions: Understanding Conformance Requirement 5

  1. when any technology that is not relied upon is turned on in a user agent,

  2. when any technology that is not relied upon is turned off in a user agent, and

  3. when any technology that is not relied upon is not supported by a user agent

In addition, the following success criteria apply to all content on the page, including content that is not otherwise relied upon to meet conformance, because failure to meet them could interfere with any use of the page:

  • 1.4.2 - Audio Control,

  • 2.1.2 - No Keyboard Trap,

  • 2.3.1 - Three Flashes or Below Threshold, and

  • 2.2.2 - Pause, Stop, Hide.


Additional Notes:

  • There is no longer a requirement that pages work without script or other programmatic objects, only that those objects meet the conformance requirements listed above.

6.4: For scripts and applets, ensure that event handlers are input device-independent. [Priority 2]

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.

2.1.3 Keyboard (No Exception): All functionality of the content is operable through a keyboard interface without requiring specific timings for individual keystrokes. (Level AAA)


Additional Notes:

  • Device-independent event handlers are not explicitly required.

6.5: Ensure that dynamic content is accessible or provide an alternative presentation or page. [Priority 2]

Conformance Requirement 1: Conformance Level: One of the following levels of conformance is met in full. Understanding Conformance Requirement 1

  • Level A: For Level A conformance (the minimum level of conformance), the Web page satisfies all the Level A Success Criteria, or a conforming alternate version is provided.

  • Level AA: For Level AA conformance, the Web page satisfies all the Level A and Level AA Success Criteria, or a Level AA conforming alternate version is provided.

  • Level AAA: For Level AAA conformance, the Web page satisfies all the Level A, Level AA and Level AAA Success Criteria, or a Level AAA conforming alternate version is provided.

Note 1: Although conformance can only be achieved at the stated levels, authors are encouraged to report (in their claim) any progress toward meeting success criteria from all levels beyond the achieved level of conformance.

Note 2: It is not recommended that Level AAA conformance be required as a general policy for entire sites because it is not possible to satisfy all Level AAA Success Criteria for some content.

Conformance Requirement 4: Only Accessibility-Supported Ways of Using Technologies: Only accessibility-supported ways of using technologies are relied upon to satisfy the success criteria. Any information or functionality that is provided in a way that is not accessibility supported is also available in a way that is accessibility supported. (See Understanding accessibility support.) Understanding Conformance Requirement 4

7.1: Until user agents allow users to control flickering, avoid causing the screen to flicker. [Priority 1]

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. See Conformance Requirement 5: Non-Interference.

2.3.2 Three Flashes: Web pages do not contain anything that flashes more than three times in any one second period. (Level AAA)

7.2: Until user agents allow users to control blinking, avoid causing content to blink (i.e., change presentation at a regular rate, such as turning on and off). [Priority 2]

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 1: For requirements related to flickering or flashing content, refer to Guideline 2.3.

Note 2: 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.

Note 3: 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 4: 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.

7.3: Until user agents allow users to freeze moving content, avoid movement in pages. [Priority 2]

The "until user agents" clause has been satisfied, so it is no longer necessary to avoid movement altogether, as long as authors do not do anything to interfere with the user's ability to pause the content. The prohibition has therefore been replaced with Success Criterion 2.2.2.

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 1: For requirements related to flickering or flashing content, refer to Guideline 2.3.

Note 2: 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.

Note 3: 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 4: 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.

7.4: Until user agents provide the ability to stop the refresh, do not create periodically auto-refreshing pages. [Priority 2]

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 essential and 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.

2.2.4 Interruptions: Interruptions can be postponed or suppressed by the user, except interruptions involving an emergency. (Level AAA)

3.2.5 Change on Request: Changes of context are initiated only by user request or a mechanism is available to turn off such changes. (Level AAA)

Specifically:

7.5: Until user agents provide the ability to stop auto-redirect, do not use markup to redirect pages automatically. Instead, configure the server to perform redirects. [Priority 2]

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 essential and 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.

3.2.5 Change on Request: Changes of context are initiated only by user request or a mechanism is available to turn off such changes. (Level AAA)

Specifically:

8.1: Make programmatic elements such as scripts and applets directly accessible or compatible with assistive technologies [Priority 1 if functionality is important and not presented elsewhere, otherwise Priority 2.]

4.1.2 Name, Role, Value: For all user interface components (including but not limited to: form elements, links and components generated by scripts), the name and role can be programmatically determined; states, properties, and values that can be set by the user can be programmatically set; and notification of changes to these items is available to user agents, including assistive technologies. (Level A)

Note: This success criterion is primarily for Web authors who develop or script their own user interface components. For example, standard HTML controls already meet this success criterion when used according to specification.

Conformance Requirement 1: Conformance Level: One of the following levels of conformance is met in full. Understanding Conformance Requirement 1

  • Level A: For Level A conformance (the minimum level of conformance), the Web page satisfies all the Level A Success Criteria, or a conforming alternate version is provided.

  • Level AA: For Level AA conformance, the Web page satisfies all the Level A and Level AA Success Criteria, or a Level AA conforming alternate version is provided.

  • Level AAA: For Level AAA conformance, the Web page satisfies all the Level A, Level AA and Level AAA Success Criteria, or a Level AAA conforming alternate version is provided.

Note 1: Although conformance can only be achieved at the stated levels, authors are encouraged to report (in their claim) any progress toward meeting success criteria from all levels beyond the achieved level of conformance.

Note 2: It is not recommended that Level AAA conformance be required as a general policy for entire sites because it is not possible to satisfy all Level AAA Success Criteria for some content.

Conformance Requirement 4: Only Accessibility-Supported Ways of Using Technologies: Only accessibility-supported ways of using technologies are relied upon to satisfy the success criteria. Any information or functionality that is provided in a way that is not accessibility supported is also available in a way that is accessibility supported. (See Understanding accessibility support.) Understanding Conformance Requirement 4

Conformance Requirement 5: Non-Interference: If technologies are used in a way that is not accessibility supported, or if they are used in a non-conforming way, then they do not block the ability of users to access the rest of the page. In addition, the Web page as a whole continues to meet the conformance requirements under each of the following conditions: Understanding Conformance Requirement 5

  1. when any technology that is not relied upon is turned on in a user agent,

  2. when any technology that is not relied upon is turned off in a user agent, and

  3. when any technology that is not relied upon is not supported by a user agent

In addition, the following success criteria apply to all content on the page, including content that is not otherwise relied upon to meet conformance, because failure to meet them could interfere with any use of the page:

  • 1.4.2 - Audio Control,

  • 2.1.2 - No Keyboard Trap,

  • 2.3.1 - Three Flashes or Below Threshold, and

  • 2.2.2 - Pause, Stop, Hide.

9.1: Provide client-side image maps instead of server-side image maps except where the regions cannot be defined with an available geometric shape. [Priority 1]

With regard to text alternatives:

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. (Refer to Guideline 4.1 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.

With regard to keyboard access:

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.


Additional Notes:

  • Server-side image maps are not keyboard accessible.

9.2: Ensure that any element that has its own interface can be operated in a device-independent manner. [Priority 2]

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.

2.1.3 Keyboard (No Exception): All functionality of the content is operable through a keyboard interface without requiring specific timings for individual keystrokes. (Level AAA)

9.3: For scripts, specify logical event handlers rather than device-dependent event handlers. [Priority 2]

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.

2.1.3 Keyboard (No Exception): All functionality of the content is operable through a keyboard interface without requiring specific timings for individual keystrokes. (Level AAA)

9.4: Create a logical tab order through links, form controls, and objects. [Priority 3]

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)

9.5: Provide keyboard shortcuts to important links (including those in client-side image maps), form controls, and groups of form controls. [Priority 3]

Accesskeys are no longer required for conformance to WCAG 2.0. It is an advisory item: Providing access keys (advisory technique for Success Criterion 2.4.1 (Level A).

10.1: Until user agents allow users to turn off spawned windows, do not cause pop-ups or other windows to appear and do not change the current window without informing the user. [Priority 2]

3.2.1 On Focus: When any component receives focus, it does not initiate a change of context. (Level A)

3.2.2 On Input: Changing the setting of any user interface component does not automatically cause a change of context unless the user has been advised of the behavior before using the component. (Level A)

3.2.5 Change on Request: Changes of context are initiated only by user request or a mechanism is available to turn off such changes. (Level AAA)

Specifically:

10.2: Until user agents support explicit associations between labels and form controls, for all form controls with implicitly associated labels, ensure that the label is properly positioned. [Priority 2]

User agents now support explicit associations of labels with form controls, so the "until user agents" clause has been satisfied. This is therefore no longer a requirement under WCAG 2.0.

"Positioning labels to maximize predictability of relationships (future link)" is listed as an advisory technique for Success Criterion 1.3.1 (Level A).

10.3: Until user agents (including assistive technologies) render side-by-side text correctly, provide a linear text alternative (on the current page or some other) for all tables that lay out text in parallel, word-wrapped columns. [Priority 3]

This "until user agents" condition has been met. Therefore, WCAG 1.0 Checkpoint 10.3 is no longer required for conformance to WCAG 2.0.

10.4 Until user agents handle empty controls correctly, include default, place-holding characters in edit boxes and text areas. [Priority 3]

This "until user agents" condition has been met. Therefore, this checkpoint is no longer required.

10.5: Until user agents (including assistive technologies) render adjacent links distinctly, include non-link, printable characters (surrounded by spaces) between adjacent links. [Priority 3]

This technique is no longer needed for user agents, but may be useful for people with cognitive disabilities.

11.1: Use W3C technologies when they are available and appropriate for a task and use the latest versions when supported. [Priority 2]

No longer required for conformance to WCAG 2.0, but relates to "accessibility supported" technologies. Refer to Understanding Accessibility Support for more information.

11.2: Avoid deprecated features of W3C technologies.

No longer required for conformance to WCAG 2.0. [Priority 2]

11.3: Provide information so that users may receive documents according to their preferences (e.g., language, content type, etc.) [Priority 3]

This checkpoint is not required by any Success Criterion in WCAG 2.0. However, a number of WCAG 2.0 Success Criterion include techniques that would allow users to adjust content based on preferences. For example, Success Criterion 1.4.4 (Level AA) includes two sufficient techniques related to providing controls and options for users related to font size.

11.4: If, after best efforts, you cannot create an accessible page, provide a link to an alternative page that uses W3C technologies, is accessible, has equivalent information (or functionality), and is updated as often as the inaccessible (original) page. [Priority 1]

Conformance Requirement 1: Conformance Level: One of the following levels of conformance is met in full. Understanding Conformance Requirement 1

  • Level A: For Level A conformance (the minimum level of conformance), the Web page satisfies all the Level A Success Criteria, or a conforming alternate version is provided.

  • Level AA: For Level AA conformance, the Web page satisfies all the Level A and Level AA Success Criteria, or a Level AA conforming alternate version is provided.

  • Level AAA: For Level AAA conformance, the Web page satisfies all the Level A, Level AA and Level AAA Success Criteria, or a Level AAA conforming alternate version is provided.

Note 1: Although conformance can only be achieved at the stated levels, authors are encouraged to report (in their claim) any progress toward meeting success criteria from all levels beyond the achieved level of conformance.

Note 2: It is not recommended that Level AAA conformance be required as a general policy for entire sites because it is not possible to satisfy all Level AAA Success Criteria for some content.

12.1: Title each frame to facilitate frame identification and navigation. [Priority 1]

2.4.1 Bypass Blocks: A mechanism is available to bypass blocks of content that are repeated on multiple Web pages. (Level A)

4.1.2 Name, Role, Value: For all user interface components (including but not limited to: form elements, links and components generated by scripts), the name and role can be programmatically determined; states, properties, and values that can be set by the user can be programmatically set; and notification of changes to these items is available to user agents, including assistive technologies. (Level A)

Note: This success criterion is primarily for Web authors who develop or script their own user interface components. For example, standard HTML controls already meet this success criterion when used according to specification.


Additional Notes:

12.2: Describe the purpose of frames and how frames relate to each other if it is not obvious by frame titles alone. [Priority 2]

This is no longer required for conformance (because the longdesc attribute type on the frame element type has not been supported and is not defined in XHTML 1.1, the Working Draft of XFrames, or the Working Draft of XHTML 2.0). The longdesc attribute is still present in the Frames Module defined in XHTML Modularization.

12.3: Divide large blocks of information into more manageable groups where natural and appropriate. [Priority 2]

2.4.10 Section Headings: Section headings are used to organize the content. (Level AAA)

Note 1: "Heading" is used in its general sense and includes titles and other ways to add a heading to different types of content.

Note 2: This success criterion covers sections within writing, not user interface components. User Interface components are covered under Success Criterion 4.1.2.

12.4: Associate labels explicitly with their controls. [Priority 2]

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

4.1.2 Name, Role, Value: For all user interface components (including but not limited to: form elements, links and components generated by scripts), the name and role can be programmatically determined; states, properties, and values that can be set by the user can be programmatically set; and notification of changes to these items is available to user agents, including assistive technologies. (Level A)

Note: This success criterion is primarily for Web authors who develop or script their own user interface components. For example, standard HTML controls already meet this success criterion when used according to specification.

Specifically:

13.1: Clearly identify the target of each link. [Priority 2]

2.4.4 Link Purpose (In Context): The purpose of each link can be determined from the link text alone or from the link text together with its programmatically determined link context, except where the purpose of the link would be ambiguous to users in general. (Level A)

2.4.9 Link Purpose (Link Only): 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. (Level AAA)

13.2: Provide metadata to add semantic information to pages and sites.

This is no longer required for conformance, but metadata can be used in a variety of ways to support WCAG 2.0. For more information, refer to Understanding Metadata.

13.3: Provide information about the general layout of a site (e.g., a site map or table of contents). [Priority 2]

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)


Additional Notes:

13.4: Use navigation mechanisms in a consistent manner. [Priority 2]

3.2.3 Consistent Navigation: Navigational mechanisms that are repeated on multiple Web pages within a set of Web pages occur in the same relative order each time they are repeated, unless a change is initiated by the user. (Level AA)

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

2.4.10 Section Headings: Section headings are used to organize the content. (Level AAA)

Note 1: "Heading" is used in its general sense and includes titles and other ways to add a heading to different types of content.

Note 2: This success criterion covers sections within writing, not user interface components. User Interface components are covered under Success Criterion 4.1.2.

13.5: Provide navigation bars to highlight and give access to the navigation mechanism. [Priority 3]

This checkpoint is not required by any Success Criterion in WCAG 2.0. It is a possible strategy to address Success Criterion 2.4.5 (Level AA). If navigation bars are used, Success Criterion 3.2.3 (Level AA) applies.

13.6: Group related links, identify the group (for user agents), and, until user agents do so, provide a way to bypass the group. [Priority 3]

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

2.4.1 Bypass Blocks: A mechanism is available to bypass blocks of content that are repeated on multiple Web pages. (Level A)


Additional Notes:

  • In WCAG 2.0, this requirement applies only to groups that are repeated on multiple delivery units.

13.7: If search functions are provided, enable different types of searches for different skill levels and preferences. [Priority 3]

This checkpoint does not directly map to any WCAG 2.0 Success Criterion and is not required. Some aspects relate to Success Criterion 2.4.2 (Level AA), Success Criterion 2.4.5 (Level AA), Success Criterion 3.3.3 (Level AA), and Success Criterion 3.3.5 (Level AAA).

13.8: Place distinguishing information at the beginning of headings, paragraphs, lists, etc. [Priority 3]

This checkpoint is not required by any Success Criterion in WCAG 2.0. The checkpoint partially maps to an advisory technique in Success Criterion 2.4.6 (Level AA), "Starting section headings with unique information."

13.9: Provide information about document collections (i.e., documents comprising multiple pages.) [Priority 3]

There is no direct mapping, but is somewhat related to Success Criterion 2.4.8 (Level AAA).

13.10: Provide a means to skip over multi-line ASCII art. [Priority 3]

This item is not required by any Success Criterion in WCAG 2.0. ASCII art is considered non-text content and is therefore covered by Success Criterion 1.1.1 (Level A).

14.1: Use the clearest and simplest language appropriate for a site's content. [Priority 1]

Some of the Level AAA success criteria in Guideline 3.1 as well as the Advisory Techniques for Guideline 3.1 aid in making content more understandable. There is no direct mapping.

14.2: Supplement text with graphic or auditory presentations where they will facilitate comprehension of the page. [Priority 3]

This checkpoint is not required by any WCAG 2.0 Success Criterion, but the following techniques listed in Success Criterion 3.1.5 (Level A) are related.

14.3: Create a style of presentation that is consistent across pages. [Priority 3]

Aspects of WCAG 1.0 Checkpoint 14.3 are required by Success Criterion 3.2.3 (Level AA), and Success Criterion 3.2.4 (Level AA). There is no Success Criterion in WCAG 2.0 that is as broad as WCAG 1.0 Checkpoint 14.3, so some aspects of it do not relate.

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