[DRAFT] Comparison of WCAG 1.0 Checkpoints to WCAG 2.0, in Numerical Order

WCAG 1.0	WCAG 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) How to Meet 1.1.1 Understanding 1.1.1 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 must be presented in non-text format, 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 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) How to Meet 1.2.1 Understanding 1.2.1 Prerecorded Audio-only: A text alternative is provided that presents equivalent information for prerecorded audio-only content. Prerecorded Video-only: Either a text alternative or an audio track is provided that presents equivalent information for prerecorded video-only content. 1.2.9 Live Audio-only: A text alternative that presents equivalent information for live audio-only content is provided. (Level AAA) How to Meet 1.2.9 Understanding 1.2.9 Additional Notes: For some types of non-text content, it may be necessary to provide a conforming alternate version. Refer to conformance requirement 1 and conformance requirement 4 for more information. Images used as bullets are also covered in Guideline 1.3 with regard to CSS usage. For framesets, `noframes` is no longer required. For multimedia, alternatives (beyond labels) are covered under Guideline 1.2. ASCII art is non-text content.
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) How to Meet 1.1.1 Understanding 1.1.1 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 must be presented in non-text format, 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 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) How to Meet 2.1.1 Understanding 2.1.1 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) How to Meet 2.4.4 Understanding 2.4.4 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 Full Text Alternative: A full text alternative for synchronized media including any interaction 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) How to Meet 1.2.3 Understanding 1.2.3 1.2.5 Audio Description: Audio description is provided for all prerecorded video content in synchronized media. (Level AA) How to Meet 1.2.5 Understanding 1.2.5 1.2.7 Audio Description (Extended): Extended audio description is provided for all prerecorded video content in synchronized media. (Level AAA) How to Meet 1.2.7 Understanding 1.2.7
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) How to Meet 1.2.2 Understanding 1.2.2 1.2.3 Audio Description or Full Text Alternative: A full text alternative for synchronized media including any interaction 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) How to Meet 1.2.3 Understanding 1.2.3 1.2.4 Captions (Live): Captions are provided for all live audio content in synchronized media. (Level AA) How to Meet 1.2.4 Understanding 1.2.4 1.2.5 Audio Description: Audio description is provided for all prerecorded video content in synchronized media. (Level AA) How to Meet 1.2.5 Understanding 1.2.5 1.2.7 Audio Description (Extended): Extended audio description is provided for all prerecorded video content in synchronized media. (Level AAA) How to Meet 1.2.7 Understanding 1.2.7
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) How to Meet 1.4.1 Understanding 1.4.1 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 5:1, except for the following: (Level AA) How to Meet 1.4.3 Understanding 1.4.3 Large Print: 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 incidental text in an image, or that are not visible to anyone, have no minimum 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) How to Meet 1.4.6 Understanding 1.4.6 Large Print: Large-scale text and images of large-scale text have a contrast ratio of at least 5:1; Incidental: Text or images of text that are part of an inactive user interface component, that are pure decoration, that are incidental text in an image, or that are not visible to anyone, have no minimum 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) How to Meet 1.4.5 Understanding 1.4.5 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) How to Meet 1.4.9 Understanding 1.4.9 Note: Logotypes (text that is part of a logo or brand name) are considered essential. Conformance Requirement 4: Accessibility-Supported Technologies Only: Only accessibility supported technologies are relied upon to satisfy the success criteria. Any information or functionality that is implemented in technologies that are not accessibility supported are also be available via technologies that are 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) How to Meet 4.1.1 Understanding 4.1.1 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: Text (but not images of text) can be resized without assistive technology up to 200 percent without loss of content or functionality. (Level AA) How to Meet 1.4.4 Understanding 1.4.4 Additional Notes: Some aspects of Success Criterion 1.4.8 (Level AAA) also relate to this checkpoint.
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) How to Meet 1.3.1 Understanding 1.3.1 2.4.10 Section Headings: Section headings are used to organize the content. (Level AAA) How to Meet 2.4.10 Understanding 2.4.10 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) How to Meet 1.3.1 Understanding 1.3.1 Specifically: H48: Using ol, ul and dl for lists
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) How to Meet 1.3.1 Understanding 1.3.1 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
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) How to Meet 3.1.2 Understanding 3.1.2
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) How to Meet 3.1.4 Understanding 3.1.4
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) How to Meet 3.1.1 Understanding 3.1.1
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) How to Meet 1.3.1 Understanding 1.3.1 Specifically: H51: Using table markup to present tabular information H63: Using the scope attribute to associate header cells and data cells in data tables
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) How to Meet 1.3.1 Understanding 1.3.1 Specifically: H43: Using id and headers attributes to associate data cells with header cells in data tables
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) How to Meet 1.3.2 Understanding 1.3.2
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) How to Meet 1.3.1 Understanding 1.3.1 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: Accessibility-Supported Technologies Only: Only accessibility supported technologies are relied upon to satisfy the success criteria. Any information or functionality that is implemented in technologies that are not accessibility supported are also be available via technologies that are accessibility supported. (See Understanding accessibility support.) Understanding Conformance Requirement 4 Conformance Requirement 5: Non-Interference: If technologies that are not accessibility supported are used on a page, or accessibility-supported technologies 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 all of the following conditions: Understanding Conformance Requirement 5 when any technology that is not accessibility-supported is turned on in a user agent, and when it is turned off in a user agent, and when it is not supported by a user agent Note: The following success criteria all apply to full pages including technologies that are not accessibility supported or relied upon to meet the other success criteria because they deal with things that could interfere with overall 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: Text alternatives are addressed in Guideline 1.1, 1.2 and 4.1. If providing a conforming alternate version, then it is as up to date as the non-conforming content, (see conformance requirement 1 and conforming alternate version).
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 satisfy and report 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: Accessibility-Supported Technologies Only: Only accessibility supported technologies are relied upon to satisfy the success criteria. Any information or functionality that is implemented in technologies that are not accessibility supported are also be available via technologies that are accessibility supported. (See Understanding accessibility support.) Understanding Conformance Requirement 4 Conformance Requirement 5: Non-Interference: If technologies that are not accessibility supported are used on a page, or accessibility-supported technologies 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 all of the following conditions: Understanding Conformance Requirement 5 when any technology that is not accessibility-supported is turned on in a user agent, and when it is turned off in a user agent, and when it is not supported by a user agent Note: The following success criteria all apply to full pages including technologies that are not accessibility supported or relied upon to meet the other success criteria because they deal with things that could interfere with overall 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) How to Meet 2.1.1 Understanding 2.1.1 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) How to Meet 2.1.3 Understanding 2.1.3 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 satisfy and report 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: Accessibility-Supported Technologies Only: Only accessibility supported technologies are relied upon to satisfy the success criteria. Any information or functionality that is implemented in technologies that are not accessibility supported are also be available via technologies that are 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) How to Meet 2.3.1 Understanding 2.3.1 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) How to Meet 2.3.2 Understanding 2.3.2
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) How to Meet 2.2.2 Understanding 2.2.2 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, (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 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 from a process, real-time or remote stream 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) How to Meet 2.2.2 Understanding 2.2.2 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, (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 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 from a process, real-time or remote stream 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) How to Meet 2.2.1 Understanding 2.2.1 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 acts to ensure that changes in content or context as a result of a time limit will not occur unexpectedly, which could prevent users from completing tasks. While exceptions to Success Criterion 2.2.1 where timing is essential exist, guideline 2.2 in general limits changes in content to those places where there is no other option. 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) How to Meet 2.2.4 Understanding 2.2.4 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) How to Meet 3.2.5 Understanding 3.2.5 Specifically: G76: Providing a mechanism to request an update of the content instead of updating automatically
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) How to Meet 2.2.1 Understanding 2.2.1 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 acts to ensure that changes in content or context as a result of a time limit will not occur unexpectedly, which could prevent users from completing tasks. While exceptions to Success Criterion 2.2.1 where timing is essential exist, guideline 2.2 in general limits changes in content to those places where there is no other option. 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) How to Meet 3.2.5 Understanding 3.2.5 Specifically: SVR1: Implementing automatic redirects on the server side instead of on the client side G110: Using an instant client-side redirect
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 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) How to Meet 4.1.2 Understanding 4.1.2 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 satisfy and report 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: Accessibility-Supported Technologies Only: Only accessibility supported technologies are relied upon to satisfy the success criteria. Any information or functionality that is implemented in technologies that are not accessibility supported are also be available via technologies that are accessibility supported. (See Understanding accessibility support.) Understanding Conformance Requirement 4 Conformance Requirement 5: Non-Interference: If technologies that are not accessibility supported are used on a page, or accessibility-supported technologies 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 all of the following conditions: Understanding Conformance Requirement 5 when any technology that is not accessibility-supported is turned on in a user agent, and when it is turned off in a user agent, and when it is not supported by a user agent Note: The following success criteria all apply to full pages including technologies that are not accessibility supported or relied upon to meet the other success criteria because they deal with things that could interfere with overall 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) How to Meet 1.1.1 Understanding 1.1.1 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 must be presented in non-text format, 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 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) How to Meet 2.1.1 Understanding 2.1.1 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) How to Meet 2.1.1 Understanding 2.1.1 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) How to Meet 2.1.3 Understanding 2.1.3
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) How to Meet 2.1.1 Understanding 2.1.1 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) How to Meet 2.1.3 Understanding 2.1.3
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) How to Meet 2.4.3 Understanding 2.4.3
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) How to Meet 3.2.1 Understanding 3.2.1 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) How to Meet 3.2.2 Understanding 3.2.2 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) How to Meet 3.2.5 Understanding 3.2.5 Specifically: H83: Using the target attribute to open a new window on user request and indicating this in link text SCR

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) How to Meet 1.1.1 Understanding 1.1.1

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 must be presented in non-text format, 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 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) How to Meet 1.2.1 Understanding 1.2.1

Prerecorded Audio-only: A text alternative is provided that presents equivalent information for prerecorded audio-only content.
Prerecorded Video-only: Either a text alternative or an audio track is provided that presents equivalent information for prerecorded video-only content.

1.2.9 Live Audio-only: A text alternative that presents equivalent information for live audio-only content is provided. (Level AAA) How to Meet 1.2.9 Understanding 1.2.9

Additional Notes:

For some types of non-text content, it may be necessary to provide a conforming alternate version. Refer to conformance requirement 1 and conformance requirement 4 for more information.
Images used as bullets are also covered in Guideline 1.3 with regard to CSS usage.
For framesets, noframes is no longer required.
For multimedia, alternatives (beyond labels) are covered under Guideline 1.2.
ASCII art is non-text content.

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) How to Meet 1.1.1 Understanding 1.1.1

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 must be presented in non-text format, 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 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) How to Meet 2.1.1 Understanding 2.1.1

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) How to Meet 2.4.4 Understanding 2.4.4

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 Full Text Alternative: A full text alternative for synchronized media including any interaction 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) How to Meet 1.2.3 Understanding 1.2.3

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

1.2.7 Audio Description (Extended): Extended audio description is provided for all prerecorded video content in synchronized media. (Level AAA) How to Meet 1.2.7 Understanding 1.2.7

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) How to Meet 1.2.2 Understanding 1.2.2

1.2.3 Audio Description or Full Text Alternative: A full text alternative for synchronized media including any interaction 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) How to Meet 1.2.3 Understanding 1.2.3

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

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

1.2.7 Audio Description (Extended): Extended audio description is provided for all prerecorded video content in synchronized media. (Level AAA) How to Meet 1.2.7 Understanding 1.2.7

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) How to Meet 1.4.1 Understanding 1.4.1

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 5:1, except for the following: (Level AA) How to Meet 1.4.3 Understanding 1.4.3

Large Print: 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 incidental text in an image, or that are not visible to anyone, have no minimum 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) How to Meet 1.4.6 Understanding 1.4.6

Large Print: Large-scale text and images of large-scale text have a contrast ratio of at least 5:1;
Incidental: Text or images of text that are part of an inactive user interface component, that are pure decoration, that are incidental text in an image, or that are not visible to anyone, have no minimum 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) How to Meet 1.4.5 Understanding 1.4.5

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) How to Meet 1.4.9 Understanding 1.4.9

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

Conformance Requirement 4: Accessibility-Supported Technologies Only: Only accessibility supported technologies are relied upon to satisfy the success criteria. Any information or functionality that is implemented in technologies that are not accessibility supported are also be available via technologies that are 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) How to Meet 4.1.1 Understanding 4.1.1

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: Text (but not images of text) can be resized without assistive technology up to 200 percent without loss of content or functionality. (Level AA) How to Meet 1.4.4 Understanding 1.4.4

Additional Notes:

Some aspects of Success Criterion 1.4.8 (Level AAA) also relate to this checkpoint.

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) How to Meet 1.3.1 Understanding 1.3.1

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

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) How to Meet 1.3.1 Understanding 1.3.1

Specifically:

H48: Using ol, ul and dl for lists

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) How to Meet 1.3.1 Understanding 1.3.1

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

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) How to Meet 3.1.2 Understanding 3.1.2

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) How to Meet 3.1.4 Understanding 3.1.4

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) How to Meet 3.1.1 Understanding 3.1.1

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) How to Meet 1.3.1 Understanding 1.3.1

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) How to Meet 1.3.1 Understanding 1.3.1

Specifically:

H43: Using id and headers attributes to associate data cells with header cells in data tables

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) How to Meet 1.3.2 Understanding 1.3.2

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) How to Meet 1.3.1 Understanding 1.3.1

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: Accessibility-Supported Technologies Only: Only accessibility supported technologies are relied upon to satisfy the success criteria. Any information or functionality that is implemented in technologies that are not accessibility supported are also be available via technologies that are accessibility supported. (See Understanding accessibility support.) Understanding Conformance Requirement 4

Conformance Requirement 5: Non-Interference: If technologies that are not accessibility supported are used on a page, or accessibility-supported technologies 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 all of the following conditions: Understanding Conformance Requirement 5

when any technology that is not accessibility-supported is turned on in a user agent, and
when it is turned off in a user agent, and
when it is not supported by a user agent

Note: The following success criteria all apply to full pages including technologies that are not accessibility supported or relied upon to meet the other success criteria because they deal with things that could interfere with overall 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:

Text alternatives are addressed in Guideline 1.1, 1.2 and 4.1.
If providing a conforming alternate version, then it is as up to date as the non-conforming content, (see conformance requirement 1 and conforming alternate version).

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 satisfy and report 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: Accessibility-Supported Technologies Only: Only accessibility supported technologies are relied upon to satisfy the success criteria. Any information or functionality that is implemented in technologies that are not accessibility supported are also be available via technologies that are accessibility supported. (See Understanding accessibility support.) Understanding Conformance Requirement 4

Conformance Requirement 5: Non-Interference: If technologies that are not accessibility supported are used on a page, or accessibility-supported technologies 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 all of the following conditions: Understanding Conformance Requirement 5

when any technology that is not accessibility-supported is turned on in a user agent, and
when it is turned off in a user agent, and
when it is not supported by a user agent

Note: The following success criteria all apply to full pages including technologies that are not accessibility supported or relied upon to meet the other success criteria because they deal with things that could interfere with overall 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) How to Meet 2.1.1 Understanding 2.1.1

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) How to Meet 2.1.3 Understanding 2.1.3

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 satisfy and report 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: Accessibility-Supported Technologies Only: Only accessibility supported technologies are relied upon to satisfy the success criteria. Any information or functionality that is implemented in technologies that are not accessibility supported are also be available via technologies that are 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) How to Meet 2.3.1 Understanding 2.3.1

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) How to Meet 2.3.2 Understanding 2.3.2

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) How to Meet 2.2.2 Understanding 2.2.2

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, (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 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 from a process, real-time or remote stream 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) How to Meet 2.2.2 Understanding 2.2.2

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, (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 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 from a process, real-time or remote stream 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) How to Meet 2.2.1 Understanding 2.2.1

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 acts to ensure that changes in content or context as a result of a time limit will not occur unexpectedly, which could prevent users from completing tasks. While exceptions to Success Criterion 2.2.1 where timing is essential exist, guideline 2.2 in general limits changes in content to those places where there is no other option. 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) How to Meet 2.2.4 Understanding 2.2.4

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) How to Meet 3.2.5 Understanding 3.2.5

Specifically:

G76: Providing a mechanism to request an update of the content instead of updating automatically

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) How to Meet 2.2.1 Understanding 2.2.1

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 acts to ensure that changes in content or context as a result of a time limit will not occur unexpectedly, which could prevent users from completing tasks. While exceptions to Success Criterion 2.2.1 where timing is essential exist, guideline 2.2 in general limits changes in content to those places where there is no other option. 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) How to Meet 3.2.5 Understanding 3.2.5

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 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) How to Meet 4.1.2 Understanding 4.1.2

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 satisfy and report 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: Accessibility-Supported Technologies Only: Only accessibility supported technologies are relied upon to satisfy the success criteria. Any information or functionality that is implemented in technologies that are not accessibility supported are also be available via technologies that are accessibility supported. (See Understanding accessibility support.) Understanding Conformance Requirement 4

Conformance Requirement 5: Non-Interference: If technologies that are not accessibility supported are used on a page, or accessibility-supported technologies 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 all of the following conditions: Understanding Conformance Requirement 5

when any technology that is not accessibility-supported is turned on in a user agent, and
when it is turned off in a user agent, and
when it is not supported by a user agent

Note: The following success criteria all apply to full pages including technologies that are not accessibility supported or relied upon to meet the other success criteria because they deal with things that could interfere with overall 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) How to Meet 1.1.1 Understanding 1.1.1

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 must be presented in non-text format, 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 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) How to Meet 2.1.1 Understanding 2.1.1

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) How to Meet 2.1.1 Understanding 2.1.1

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) How to Meet 2.1.3 Understanding 2.1.3

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) How to Meet 2.1.1 Understanding 2.1.1

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) How to Meet 2.1.3 Understanding 2.1.3

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) How to Meet 2.4.3 Understanding 2.4.3

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) How to Meet 3.2.1 Understanding 3.2.1

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) How to Meet 3.2.2 Understanding 3.2.2

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) How to Meet 3.2.5 Understanding 3.2.5

Specifically:

[DRAFT] Comparison of WCAG 1.0 Checkpoints to WCAG 2.0, in Numerical Order

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New WCAG 2.0 requirements not mentioned in the comparison table below

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