Web Content Accessibility Guidelines 2.0

Principle 1: Content must be Perceivable.

Guideline 1.1 For non-text content, provide text equivalents that serve the same purpose or convey the same information as the non-text content, except when the purpose of the non-text content is to create a specific sensory experience (for example, music and visual art) in which case a text label or description is sufficient.

Level 1 Success Criteria for Guideline 1.1

text equivalents are explicitly associated with non-text content, except when the non-text content is intended to create a specific sensory experience (for example, music without words and visual art). [X]
- the text equivalent fulfills the same function as the author intended for the non-text content (that is, it conveys all of the intended information and achieves the same function as the non-text content).
non-text content that is designed to create a specific sensory experience (such as music without words or visual art) has a text label or a text description explicitly associated with it. [X]

Level 2 Success Criteria for Guideline 1.1

No level 2 success criteria for this guideline.

Level 3 Success Criteria for Guideline 1.1

a text document (for example, a movie script) is provided that includes all important visual information, dialogue, and other important sounds. [X]

Guideline 1.1 (text-equiv) Issues

Who Benefits from Guideline 1.1 (Informative)

People who are blind, have low vision, have cognitive disabilities or have trouble reading text for any reason can have the text read aloud to them by assistive technology.
People who are deaf, are hard of hearing, or who are having trouble understanding audio information for any reason can read the text presentation or have it translated and presented as sign language by assistive technology.
People who are deaf-blind can read the text in braille.

Examples of Guideline 1.1 (Informative)

Example 1: an image used as a button. (short equivalent for function)

A right arrow icon is used to link to the next slide in a slide show. The text equivalent is "Next Slide," so that a screen reader would read the phrase "Next Slide" and automatically identify it as a link by adding the word link or changing the synthesizer's voice.
Example 2: a data chart. (short label + longer description)

A bar chart compares how many widgets were sold in June, July, and August. The short label says, "Figure one - Sales in June, July and August." The longer description identifies the type of chart or graph, provides a high-level summary of the data comparable to that available from the chart or graph, and provides the data themselves in a table or other accessible format.
Example 3: an animation. (short label + longer description)

An animation shows how to tie a knot. The short label says, "An animation showing how to tie a square knot." The longer explanation describes the hand movements needed to tie the knot.
Example 4: an audio file of a speech. (short label + transcript)

An audio file is embedded in a Web page. The short label says, "Chairman's speech to the assembly." A link to a text transcript is provided immediately after the audio clip.
Example 5: an audio file of a symphony. (short label)

An audio file is embedded in a Web page. The short label says, "Beethoven's 5th Symphony performed by the Vienna Philharmonic Orchestra."

Guideline 1.2 Provide synchronized media equivalents for time-dependent presentations.

Level 1 Success Criteria for Guideline 1.2

Editorial Note: There is discussion about moving some of the current success criteria from Level 1 to Level 2. The issue stems from trying to apply the success criteria to every Web cam, newscast, and home broadcast. Another approach is to allow a conformance claim to state, for example, "All pages and applications on this site meet the Level 1 guidelines of WCAG 2.0 except the Web cam at http://example.org/webcam/."

an audio description of visual events is provided for audio-visual media. [X]
captions are provided for all significant dialogue and sounds in time-dependent material. [X]

Editorial Note: A definition for "time dependent" is needed that explains that it includes audio and visual information presented at the same time, as well as audio or visual with interaction, or in combination with real-time events.
[begin proposed]
Exception:
A text transcript or other non-audio equivalent that is not synchronized with the multimedia presentation satisfies this success criterion if all four of the following statements about the content are true:
1. the content is real-time and
2. the content is audio-only and
3. the content is not time-sensitive and
4. the content is not interactive
[Issue #597]
[end proposed]
[begin current]

Exception:

If the Web content is real-time and audio-only and not time-sensitive and not interactive a transcript or other non-audio equivalent is sufficient.

Editorial Note: This exception also applies to item 3.

[end current]
descriptions and captions are synchronized with the events they represent. [X]
[begin proposed]
Exception:
A text transcript or other non-audio equivalent that is not synchronized with the multimedia presentation satisfies this success criterion if all four of the following statements about the content are true:
1. the content is real-time and
2. the content is audio-only and
3. the content is not time-sensitive and
4. the content is not interactive
[Issue #598]
[end proposed]
[begin proposed] if the Web content is real-time video with audio, real-time captions are provided. [Issue #599] [X] [end proposed]

[begin current] if the Web content is real-time video with audio, real-time captions are provided unless the content: [X] [end current]

[begin proposed]

Exception:

If the content is a music program that is primarily non-vocal, then captions are not required.

[end proposed]
[begin current]
- is a music program that is primarily non-vocal
[end current]

[begin proposed] if the Web content is real-time, non-interactive video (for example, a Webcam view of surrounding conditions such as weather information), then one of the following is provided: [Issue #600] [X] [end proposed]
- [begin proposed]
  an equivalent that conforms to Guideline 1.1 (for example, an ongoing text report of weather conditions)
  [end proposed]
- [begin proposed]
  a link to an equivalent that conforms to Guideline 1.1 (for example, a link to a weather Web site that conforms to Guideline 1.1)
  [end proposed]
[begin current] if the Web content is real-time non-interactive video (e.g., a Webcam of ambient conditions), either provide an equivalent that conforms to guideline 1.1 (e.g., an ongoing update of weather conditions) or link to an equivalent that conforms to guideline 1.1 (e.g., a link to a weather Web site). [X] [end current]
[begin proposed] if a presentation that contains only audio or only video requires users to respond interactively at specific times during the presentation, then a synchronized equivalent presentation (audio, visual or text) is provided. [Issue #601] [X] [end proposed]

[begin current] if a pure audio or pure video presentation requires a user to respond interactively at specific times in the presentation, then a time-synchronized equivalent (audio, visual or text) presentation is provided. [X] [end current]

[begin proposed]

Exception:

If content that is rebroadcast from another medium or resource meets accessibility requirements for that medium, then the rebroadcast satisfies this checkpoint if it complies with other applicable sections of WCAG 2.0

[end proposed]

[begin current]

Exception:

if content is rebroadcast from another medium or resource that complies to broadcast requirements for accessibility (independent of these guidelines), the rebroadcast satisfies the guideline if it complies with the other guidelines.

[end current]

Level 2 Success Criteria for Guideline 1.2

Editorial Note: This whole guideline (1.2) needs reworking. Perhaps move some down from above, or limit the items above to just certain classes of content - and then put the rest of the coverage (for other types of content) here.

[begin proposed] synchronized captions and audio descriptions are provided for all live broadcasts. [Issue #602] [X] [end proposed]

[begin current] captions and audio descriptions are provided for all live broadcasts. [X] [end current]

Level 3 Success Criteria for Guideline 1.2

[begin proposed] the presentation does not require the user to read captions and follow the visual presentation simultaneously [Issue #602] [Y] [end proposed]

[begin current] the presentation does not require the user to read captions and the visual presentation simultaneously in order to understand the content. [Y] [end current]

Guideline 1.2 (media-equiv) Issues

Who Benefits from Guideline 1.2 (Informative)

People who are deaf or have a hearing loss can access the auditory information through captions.
People who are blind or have low vision as well as those with cognitive disabilities who have difficulty interpreting visually what is happening benefit from audio descriptions of visual information.

People without disabilities also benefit from media equivalents:

People in noisy environments or with muted sound often rely on captions.
Captions help many people to develop language and reading skills.
Audio descriptions provide visual information for people who are temporarily looking away from the video presentation, for example, when following an instructional video and looking at their hands.
Captions and text descriptions make it possible to index and search media files.

Note:

Time-dependent presentations that require people to use a single sense to follow two or more things at the same time may present significant barriers to some users. Depending on the nature of the presentation, it may be possible to avoid scenarios where, for example, a deaf user would be required to watch an action on the screen and read the captions at the same time. However, this may not be available for live broadcasts (e.g. a football game). Where possible (especially for education and training materials), provide content so that it does not require tracking multiple simultaneous events with the same sense, or, give the user the ability to freeze the video so that captions can be read without missing the video.

Examples of Guideline 1.2 (Informative)

Example 1: a movie clip with audio description and captions.

A clip from a movie is published on a Web site. In the clip, a child is trying to attract a puppy to the child's bedroom by laying a trail of crumbs since the soundtrack includes only the child's mumbling. The audio description that is heard when the child stops mumbling says "Charlie puts a crumb on each stair leading to his room." The caption that appears as he mumbles reads, "[inaudible mumbling]."
Example 2: a video clip of a news story.

A video clip accompanies a news story about flooding in a major city. The reporter gives a verbal description of the scene. No audio description is necessary. The captions display what the reporter is saying.
Example 3: a silent animation.

An animation shows a pantomime with a white face and black costume climbing an invisible ladder. There is no audio track for this animation. No captions or audio description are required. Instead, a text label and description are provided as required by guideline 1.1.

[begin proposed]

Guideline 1.3 Make information, structure, and functionality recognizable even when users or user agents change the presentation format. -- OR -- Preserve information, structure, and functionality when changing visual or auditory presentation format.

[end proposed]

[Issue #603]

[begin current]

Information, functionality, and structure are separable from presentation.

[end current]

Level 1 Success Criteria for Guideline 1.3

[begin proposed]
data models or markup are used to enable assistive technology to recognize relationships among content elements, including (but not limited to) those listed below: [Issue #604]
[end proposed]
[begin proposed]
1. hierarchical elements and relationships, such as headings, paragraphs and lists
2. non-hierarchical relationships between elements such as:
  - cross-references and linkages,
  - associations between labels and controls,
  - associations between table cells and their headers
  Editorial Note: JS: these should probably be listed as examples of hierarchical relationships instead of non-hierarchical
3. emphasis on specific words and phrases
[end proposed]
[begin current]
the following can be derived programmatically (i.e. through a markup or data model that is assistive technology compatible) from the content without requiring user interpretation of presentation.
[end current]
[begin current]
1. any hierarchical elements and relationships, such as headings, paragraphs and lists
2. any non-hierarchical relationships between elements such as cross-references and linkages, associations between labels and controls, associations between cells and their headers, etc.
3. any emphasis
[end current]
[begin proposed] any information presented through color is also available without color (for example through context or markup or coding that does not depend on color). [Issue #317] [X] [end proposed]

[begin current] any information presented through color is also available without color (e.g. through context or markup or non-color dependent coding). [X] [end current]
[begin proposed] text is not presented over a background image or pattern, or if a background image or pattern is present the the text is easily readable when the page is viewed in black and white. [Issue #605] [Y] [end proposed]

[begin current] text content is not presented over a background image or pattern OR the text is easily readable when the page is viewed in black and white (no grayscale). [Y] [end current]

Level 2 Success Criteria for Guideline 1.3

[begin proposed] information presented using color is also available without color, for example through context or markup or coding that does not depend on color. [Issue #317] [Y] [end proposed]

[begin current] any information presented using color is also available without color and without having to interpret markup. [Y] [end current]

Level 3 Success Criteria for Guideline 1.3

No level 3 success criteria for this guideline.

Guideline 1.3 (content-structure-separation) Issues

Who Benefits from Guideline 1.3 (Informative)

Separating content and structure from presentation allows Web pages to be presented differently to meet the needs and constraints of different users without losing any of the information or structure. For example, information can be presented via speech or braille (text) that was originally intended to be presented visually.
It can also facilitate automatic emphasis of structure or more efficient navigation.
All of these can benefit people with cognitive, physical, hearing, and visual disabilities.

Examples of Guideline 1.3 (Informative)

Example 1: a multi-column document.

A document is marked up with headings, paragraphs and other structural features. It is presented visually in three columns. The markup that creates the columns is separate from the markup that specifies the logical structure of the document.
Example 2: a scrolling list of stock prices.

Current stock quotes are scrolled horizontally across the screen. The data are separate from the methods used to scroll the text across the page.
Example 3: a 3-dimensional site map.

A custom user interface renders 3D visualizations of the pages on a site and how they relate to one another from a data source. Any hierarchical relationships, groupings, cross-references, etc. would originate in the data source so that alternate interfaces could be rendered (from the same source) that expose the structure of the site in an accessible form. (See also guideline 4.3)
Example 4: a list that allows users to sort information on a page according to preference.

A script allows a user to rearrange a categorical listing of music files by date, artist, genre, or file size. The script updates both the structure and the presentation accordingly when generating alternate views.

[begin proposed]

Guideline 1.4 For text, use fonts that can be represented in Unicode.

[end proposed]

[Issue #606]

[begin current]

All text can be decoded into words represented in Unicode.

[end current]

Level 1 Success Criteria for Guideline 1.4

Editorial Note: The CKW reorganization suggested that this guideline be combined with guideline 3.2. [I#442]

[begin proposed] text is provided in Unicode or can be automatically converted to Unicode -- OR -- text is provided in Unicode or information is available in metadata that enables automatic conversion to Unicode. [Issue #607] [X] [end proposed]

[begin current] text in the content is provided in Unicode or sufficient information is provided so that it can be automatically mapped back to Unicode. [X] [end current]

Level 2 Success Criteria for Guideline 1.4

[begin proposed] abbreviations and acronyms are clearly identified each time they occur if they are identical to a word in the document's language that has a different meaning. (See also guideline 3.1) [Issue #341] [X] [end proposed]

[begin current] abbreviations and acronyms are clearly identified each time they occur if they collide with a word in the standard language that would also logically appear in the same case (e.g. all caps). (See also guideline 3.1) [X] [end current]
[begin proposed] symbols such as diacritic marks that are found in standard usage of the natural language of the content, and that are necessary for precise identification of words, are present, or another standard mechanism for clear identification is provided. [Issue #608] [X] [end proposed]

[begin current] symbols such as diacritic marks that are found in standard usage of the natural language of the content, and that are necessary for unambiguous identification of words, are present or another standard mechanism for disambiguation is provided. [X] [end current]

Level 3 Success Criteria for Guideline 1.4

No level 3 success criteria for this guideline.

Guideline 1.4 (unambiguous-decoding) Issues. Kerstin's summary of issues around guideline 1.4.

Who Benefits from Guideline 1.4 (Informative)

Facilitating unambiguous decoding of characters and words in content is also helpful for individuals who are learning to read or learning a second language.

Examples of Guideline 1.4 (Informative)

Example 1: an acronym in a page title.

In the following heading, "People of the W3C." the acronym "W3C" is marked as an acronym. Because it has been marked appropriately, the user agent would be able to speak the letters of the acronym one at a time rather than attempting to pronounce it as though it were a word.

Guideline 1.5 Make structure perceivable -- OR -- Make structure perceivable through presentation [level 2 guideline]

[Issue #439]

[begin current]

Structure has been made perceivable through presentation.

[end current]

Level 1 Success Criteria for Guideline 1.5

No level 1 success criteria for this guideline

Level 2 Success Criteria for Guideline 1.5

[begin proposed] structural elements can be recognized by the way they look, the way they sound, or both. [Issue #609] [Y] [end proposed]

[begin current] the structural elements present have a different visual appearance or auditory characteristic from each other and from body text. [Y] [end current]

Editorial Note: NRT (5 Nov 2003): Could probably be rewritten to be testable. Body text is a structural element, may be too technology specific. Not sure what this means for a form. (Untestable Success Criteria)

Level 3 Success Criteria for Guideline 1.5

[begin proposed] structural emphasis is evident on multiple display devices, (for example, black and white monitors, small screens, monaural audio playback devices, etc.). [Issue #610] [Y] [end proposed]

[begin current] the structural emphases are chosen to be distinct on different major visual display types (e.g. black and white, small display, mono audio playback). [Y] [end current]

Editorial Note: NRT (5 Nov 2003): Not testable unless we define the major visual display types. But if we do that, then it will be incomplete as soon as a new display type is invented. (Untestable Success Criteria)
[begin proposed] content is constructed so that users can change the visual appearance or auditory properties of structural elements. [Issue #611] [Y] [end proposed]

[begin current] content is constructed such that users can control the presentation of structural elements or the emphasis on the structure can be varied through alternate presentation formats. [Y] [end current]

Editorial Note: : The following items are techniques and would be moved to the techniques gateway.

[begin proposed] to emphasize structure visually, use font variations, styles, and sizes in addition to white space, color, and graphics. [Issue #612] [Y] [end proposed]

[begin current] for visual presentations, font variations, styles, size and white space can be used to emphasize structure. [Y] [end current]
[begin proposed] [Issue #613] [Y] [end proposed]

[begin current] color and graphics can be used to emphasize structure. [Y] [end current]
[begin proposed] to emphasize structure audibly, use different voice characteristics and other sounds to indicate section headings and other structural elements. [Issue #614] [Y] [end proposed]

[begin current] for auditory presentations, different voice characteristics and/sounds can be used for major headings, sections and other structural elements. [Y] [end current]

Editorial Note: JS 10/25: Do we want to say, "...then an alternate presentation that features additional graphics, etc."? or are we recommending changes to the default presentation?
[begin proposed] if the default presentation of the structure is not distinct enough to meet the needs of a specific user group within the audience for the content, then additional graphics, colors, sounds, and other aspects of presentation can be used to emphasize the structure. [Issue #615] [Y] [end proposed]

[begin current] if content is targeted for a specific user group and the presentation of the structured content is not salient enough to meet the needs of your audience, additional graphics, colors, sounds, and other aspects of presentation can be used to emphasize the structure. [Y] [end current]

Guideline 1.5 (structure-emphasis) Issues

Who Benefits from Guideline 1.5 (Informative)

Presentation that emphasizes structure:

enables users with cognitive and visual disabilities to orient themselves within the content,
enables all users to move quickly through the content and notice major content divisions
enables all users, but particularly users with visual or cognitive disabilities to focus on important content,
enables all users, but particularly users with visual or cognitive disabilities to distinguish the different types of content.

Examples of Guideline 1.5 (Informative)

Example 1: documentation for a product.

Identifying chapters in the structure of a book is appropriate and accepted use of labeling the structure. Within the chapters, headings identify (label) changes in context and highlight ideas contained in the following text. Subtle differences between the appearance of the chapter title and the section headings helps the user understand the hierarchy and relationship between the title and headings. The only difference might be font size and margin indentation when presented visually, and spoken in a difference voice or preceded by a sound when presented auditorily.
Example 2: a data table.

Groups of rows or columns are labeled with headers.
Example 3: an audio presentation.

An audio rendering of a document, generated according to a style sheet, uses a different, more formal voice to read titles and headers so the listener can easily identify the words as a title and not part of the running text.

Guideline 1.6 In visual presentations, make it easy to distinguish foreground words and images from the background.

Level 1 Success Criteria for Guideline 1.6

Any text that is presented over a background is electronically available so that it could be re-presented in a form that allows the text to be distinguished from the background. [X]

Note:

Note: text that meets guideline 1.1 should satisfy this criterion.

Level 2 Success Criteria for Guideline 1.6

text that is presented over a background has a contrast greater than ____ between the text and the background as measured by ___ or the page provides a mechanism to allow the text to meet this criterion. [Y]

Editorial Note: The working group is seeking an algorithm that measures contrast in a way that is accurate and testable enough that we could include it in the guidelines. One algorithm, which comes from the Techniques For Accessibility Evaluation And Repair Tools document, is currently under consideration for inclusion in the techniques, but the group has not yet found something that is specific enough to be included at the guidelines level. Previous working drafts included criteria to address contrast when content was presented in 256 grayscale. These criterion have been removed for now because it may be that the algorithm described above will address this issue.

Level 3 Success Criteria for Guideline 1.6

No level 3 success criteria for this guideline.

Guideline 1.6 (visual-contrast) Issues

Who Benefits from Guideline 1.6 (Informative)

Individuals with low vision can easily make out characters in the content even if they don't have the wide field of view or full range of color perception used by fully sighted persons to separate text from background images.

Examples of Guideline 1.6 (Informative)

Example 1: a background image on a page.

A background image and text are arranged so that there is no image behind the text or the image is so faint that the difference between the darkest part of the image and the text (which is dark) meets the standard foreground/background contrast requirements. The image behind the text also does not contain lines that are about the same width as the characters so they do not interfere with character recognition.

Guideline 1.7 In default auditory presentations, make it easy to distinguish foreground speech and sounds from background sounds. [level 2 guideline]

Level 1 Success Criteria for Guideline 1.7

No level 1 success criteria for this guideline

Level 2 Success Criteria for Guideline 1.7

No level 2 success criteria for this guideline.

Level 3 Success Criteria for Guideline 1.7

audio content does not contain background sounds OR the background sounds are at least 20 decibels lower than the foreground audio content with the exception of occasional short sounds. [Y]

Note:

A 20 decibel difference in sound level is roughly 4 times quieter (or louder). Background sound that meets this requirement will be approximately four times (4x) quieter than the foreground audio content.

Guideline 1.7 (audio-contrast) Issues

Who Benefits from Guideline 1.7 (Informative)

Individuals with hearing impairments that limit their ability to hear all of the frequencies of speech can make out the words from the sounds they can hear because they are not mixed with residual sounds from the music.

Examples of Guideline 1.7 (Informative)

Example 1: speech over background sounds.

Because speech is often naturally mixed with background sounds (movies, live news etc) and cannot be easily removed or separated, captions are provided (under guideline 1.2) to make dialog understandable. However not all people can see or read the captions. Where speech is mixed or recorded so that it is at least 20 db above any background sounds, most people do not need to rely on captions to understand the dialog.

[begin proposed]

Principle 2: OPERABLE. Any user should be able to operate all Interface Elements that are part of the content

[end proposed]

[Issue #622]

[begin current]

Principle 2: OPERABLE. Ensure that Interface Elements in the Content are Operable by Any User

[end current]

Guideline 2.1 Make all functionality operable via a keyboard or a keyboard interface.

Level 1 Success Criteria for Guideline 2.1

all of the functionality of the content, where the functionality or its outcome can be described in a sentence, is operable through a keyboard or keyboard interface. [X]

Note:

This includes author-provided accessibility features.

Note:

Other interfaces (such as a mouse) can be provided in addition to keyboard operation.

Note:

Refer to guideline 4.2 for information regarding user agent support.

Level 2 Success Criteria for Guideline 2.1

wherever a choice between input device event handlers is available and supported, the more abstract event is used. [X]

Level 3 Success Criteria for Guideline 2.1

all of the functionality of the content is operable via a keyboard or keyboard interface.

Guideline 2.1 (keyboard-operation) Issues

Who Benefits from Guideline 2.1 (Informative)

Individuals who are blind (and cannot use pointing devices) can have access to the functionality of the Web content or site.
Individuals with severe physical disabilities can use speech input (which simulates keystrokes) to both enter data and operate the interface elements on the page.

Examples of Guideline 2.1 (Informative)

Example 1: operation with multiple input devices.

The content relies only on focus-in, focus-out, and activation events; these are defined in the API of the environment for which the content is written, and are intended to be operable by a variety of input devices, including pointing devices, keyboards and speech input systems.
Example 2: examples of Web content that would and would not be operable from a keyboard or keyboard interface
- If it's written to be operable from a computer keyboard, it conforms. (because it is operable from the keyboard.)
- If it's written to be used on a device that doesn't usually have a keyboard such as a cell phone, but it can be controlled by an optional keyboard for that device, it conforms. (A person who needs a keyboard - or alternate keyboard - can use it to control the application.)
- If it's written to be used with a device that doesn't have a keyboard, but it could also be used by similar devices that do and it would work with their keyboard, it conforms. (A person who needs a keyboard would not buy the device without the keyboard. That device may itself not be considered accessible. But the content can be controlled from a device with a keyboard and therefore conforms to this guideline.)
- If it's written to work with devices that do not have keyboards and it can not be used by any other devices that do have keyboards, then it does not conform. (It cannot be accessed via keyboard.)

Guideline 2.2 Allow users to control time limits on their reading or interaction unless specific real-time events or rules of competition make such control impossible.

Level 1 Success Criteria for Guideline 2.2

content is designed so that time limits are not an essential part of interaction, or at least one of the following is true for each time limit: [X]
- the user is allowed to deactivate the time limit or;
- the user is allowed to adjust the time limit over a wide range which is at least ten times the length of the default setting or;
- the user is warned before time expires, allowed to extend the time limit with a simple action (for example, "hit any key") and given at least 10 seconds to respond or;
- the time limit is an important part of a real-time event (for example, an auction), and no alternative to the time limit is possible or;
- the time limit is part of an activity where timing is an essential part of the activity (for example, competitive gaming or time-based testing) and time limits can not be extended further without invalidating the activity.

Level 2 Success Criteria for Guideline 2.2

the user is allowed to turn off content that blinks for more than 3 seconds.
The user is allowed to pause and/or permanently stop moving or time-based content.

Level 3 Success Criteria for Guideline 2.2

the content has been designed in a way that any time limits in the content would pass level 1, success criteria 1 for this guideline without exceptions. [Y]

Editorial Note: Real time events would not be allowed with this wording. Do we want to accept them?
any non-emergency interruptions, such as the availability of updated content, can be postponed and/or suppressed by the user. [Y]

Guideline 2.2 (time-limits) Issues

Who Benefits from Guideline 2.2 (Informative)

People with reading disabilities, cognitive disabilities, and learning disabilities often need more time than most people to read and comprehend written text. People with physical disabilities benefit from increased time limits since they might not be able to move quickly or accurately enough to interact with moving objects or may take longer than usual to interact with the user interface elements.
reading disabilities, cognitive disabilities, and learning disabilities often need more time than most people to read and comprehend written text. People with physical disabilities can access content that is updated often in cases where content might not be processed and read before being refreshed or when read out of order an assistive technology or voice browser.People with

Examples of Guideline 2.2 (Informative)

Examples of content that must meet the success criteria of this checkpoint::
- automatic refresh
- redirection
- blinking or scrolling text
- dialog that disappears after a short period
- shutdown or deactivation of page if activity is not received in a set amount of time
Example 1: blinking text.

Client-side scripting is used to create blinking text. The content provides an option that allows the user to turn off the blinking.
Example 2: a news site that is updated regularly.

A news site causes its front page to be updated every half hour. The front page contains minimal text and primarily consists of links to content. A user who does not wish the page to update selects a checkbox. The checkbox is in the "user preferences" portion of the site which is one of the first links on each page.

[begin proposed]

Guideline 2.3 Allow users to avoid content that is designed to flicker.

[end proposed]

[Issue #630]

[begin current]

User can avoid experiencing screen flicker.

[end current]

Level 1 Success Criteria for Guideline 2.3

Editorial Note (06/10/03): This guideline is currently a level 1 success criterion because the WCAG WG expects that it will be possible to test content for flicker and the result will be a flicker rate in Hz that can be stored in a machine-readable format. If the assumption regarding a testing tool does not hold at time of final review of these guidelines, this criterion will be moved to level 2."

At least one of the following is true: [Issue #631] [Y]
1. [begin proposed]
  content was not designed to flicker (or flash) in the range of 3 to 49 Hz (between 3 to 49 times per second).
  [end proposed]
  
  [begin current]
  content was not designed to flicker (or flash) in the range of 3 to 49 Hz.
  [end current]
  
  Editorial Note: NRT (5 Nov 2003): only testable by designer of site (Untestable Success Criteria)
2. [begin proposed]
  if flickering content must be used, users are warned about the flicker before they go to the page, and are informed that an alternative version has been provided which approximates the original version as closely as possible without flickering.
  [end proposed]
  
  [begin current]
  if flicker is unavoidable, the user is warned of the flicker before they go to the page, and as close a version of the content as is possible without flicker is provided.
  [end current]
Editorial Note: We would like to include a third criteria here that would state that a test that was conducted and the pages passed. No test or tool exists yet though. We're looking into how such a test and/or tool might be designed.

Level 2 Success Criteria for Guideline 2.3

animation or other content does not visibly or purposely flicker between 3 and 49 Hz. [Y]

Editorial Note: NRT (5 Nov 2003): "other content" is too broad. "visibly" is not testable. Assumes tool can be developed that can determine if flicker falls within the 3 to 49 Hz range. (Untestable Success Criteria)
content that might create a problem has been tested [using XYZ tool]; only pages with unavoidable flicker remain and appropriate warnings along with a close alternative presentation have been provided for these pages. [Y]

Level 3 Success Criteria for Guideline 2.3

No level 3 success criteria for this guideline.

Guideline 2.3 (flicker) Issues

Who Benefits from Guideline 2.3 (Informative)

Individuals with photosensitive epilepsy can have seizures triggered by flickering or flashing in the 3 to 49 flashes per second (Hertz) range with a peak sensitivity at 20 flashes per second.
Individuals who are easily distracted may not be able to focus on page content with flicker occurring in the same visual field.

[begin proposed]

Guideline 2.4 Make it easy for users to browse the resource, to know their place in it, and to find information they need -- OR -- Content includes mechanisms to facilitate orientation and movement [level 2 guideline]

[end proposed]

[Issue #632]

[begin current]

Mechanisms have been added to facilitate orientation and movement in content.

[end current]

Level 1 Success Criteria for Guideline 2.4

No level 1 success criteria for this guideline

Level 2 Success Criteria for Guideline 2.4

Editorial Note: The CKW reorganization proposed that all of the items in required be removed and proposed a rewording of the item in level 2 that addressed logical, linear reading order. [I#441]

In documents greater than 50,000 words or sites larger than 50 perceived pages, at least one of the following is provided. [Issue #633] [Y]

Editorial Note: NRT (5 Nov 2003): What's a perceived page? What if it's a voice XML application. How does it apply to web applications? (Untestable Success Criteria)
1. [begin proposed]
  markup to identify hierarchical structure and other, non-hierarchical relationships such as cross-references, internal links, etc.
  [end proposed]
  
  [begin current]
  hierarchical structure mark up
  [end current]
  
  Editorial Note: NRT (5 Nov 2003): Does this apply to a page or the site as a whole? (Untestable Success Criteria)
2. [begin proposed]
  table of contents
  [end proposed]
  
  [begin current]
  Table of contents (or site map)
  [end current]
3. [begin proposed]
  site map
  [end proposed]
4. [begin proposed]
  alternate display orders
  [end proposed]
  
  [begin current]
  alternate display orders (or alternate site navigation mechanisms)
  [end current]
  
  Editorial Note: NRT (5 Nov 2003): What is an alternate display order of a 50-page site? (Untestable Success Criteria)
5. [begin proposed]
  alternate site navigation mechanisms
  [end proposed]
[begin proposed] large blocks of material that are repeated on multiple pages, such as navigation menus with more than 7 links, site banners, etc., can be bypassed by people who use screen readers or who navigate via keyboard or keyboard interface. [Issue #634] [Y] [end proposed]

[begin current] Users are able to skip over large blocks of repetitive material, navigational bars or other blocks of links that are greater than 7 when reading with a synthesizer or navigating using keyboard.[I#323] [Y] [end current]

Editorial Note: NRT (5 Nov 2003): Contains ambiguous words: skip, large, repetitive (Untestable Success Criteria)

Level 3 Success Criteria for Guideline 2.4

the content has been reviewed, taking into account the following strategies for facilitating orientation and movement, applying them as appropriate. [Issue #635] [Y]

Editorial Note: NRT (5 Nov 2003): "has been reviewed" is is only testable by someone internal to the development organization. (Untestable Success Criteria)
1. breaking up text into logical paragraphs
2. [begin proposed]
  dividing documents, especially very long ones, into hierarchical sections and subsections with clear and informative titles
  [end proposed]
  
  [begin current]
  providing hierarchical sections and titles, particularly for longer documents
  [end current]
3. [begin proposed]
  supplying a unique and informative title for each page or resource that can be accessed independently (for example, from a search results page)
  [end proposed]
4. [begin proposed]
  revealing important non-hierarchical relationships, such as cross-references, or the correspondence between header and data cells in a data table, so that the relationships are represented unambiguously in the markup or data model.
  [end proposed]
  
  Editorial Note: JS 10/27: I don't understand the relationship between "revealing" relationships and representing them in the markup. Who or what does the revealing, and how?]
  
  [begin current]
  revealing important non-hierarchical relationships, such as cross-references, or the correspondence between header and data cells in a table, so that they are represented unambiguously in the markup or data model
  [end current]
5. dividing very large works into sections and or chapters with logical labels
  
  Editorial Note: JS 10/27: seems redundant with B, above
6. others?
[begin proposed] information is provided that would allow an assistive technology to determine at least one logical sequence in which to read a document. [Issue #636] [X] [end proposed]

[begin current] information is provided that would allow an assistive technology to determine at least one logical, linear reading order. [X] [end current]

Editorial Note: NRT (5 Nov 2003): "logical, linear, reading order" is not testable. (Untestable Success Criteria)
[begin proposed] diagrams are constructed so that they have structure that users can access. [Issue #637] [X] [end proposed]

Editorial Note: JS 10/26: Does this belong somewhere under Principle 1, since it seems to have more to do with making structure perceivable than making it operable? Or should we revise this to bring out the operable characteristics of the diagram?

[begin current] diagrams are constructed in a fashion so that they have structure that can be accessed by the user. [X] [end current]
[begin proposed] logical tab order has been created where possible. [Issue #638] [X] [end proposed]

[begin current] where possible, logical tab order has been created.[I#319] [X] [end current]

Editorial Note: NRT (5 Nov 2003): "logical tab order" is not testable. (Untestable Success Criteria)

Guideline 2.4 (navigation-mechanisms) Issues

Who Benefits from Guideline 2.4 (Informative)

When the logical structure is provided in markup or a data model,
- Users with physical disabilities can use structure to more easily jump between paragraphs, chapters, sections etc.
- Users with cognitive disabilities can use structure (chapter titles, headers, etc.) to provide more context for the text that follows them. They also provide warning of a change in context and reorient the user to the new focus.
- Users with blindness or low vision can jump from header to header to get an overview or to more quickly "skim" to the section they are interested in.
- Readers with low vision can sometimes (depending on display technology) change how chapter titles and headers are displayed to make them more visible -and easier to use when skimming the document.
- the content can be presented on a variety of devices because the device software can choose only those elements of the content that it is able to display and display them in the most effective way for that device.
Providing different navigation mechanisms can provide a better match between different people's skills, background knowledge, visual vs. text orientation, and the type of information they are seeking at the moment.
Individuals with cognitive disabilities may find it easier to ask for what they want than to deduce its location from categorical choices.
Individuals with low vision or blindness may find search techniques that fetch everything that relates to a topic of interest to be easier than techniques that require them to scan lists or pages for the items.

Examples of Guideline 2.4 (Informative)

Example 1: a physics dissertation.

A dissertation contains well-defined sections such as "Abstract," "Table of Contents," "Chapter 1," etc. The pieces in each section (paragraphs, subheadings, quotes) are denoted with structural markup.
Example 2: a scalable image of a bicycle.

Lines and a circle (spokes and rim) are grouped into a "wheel." Lines in a triangle that attach to each wheel are grouped into a "frame."
Example 3: user interface.

User interface controls are divided into organized groups.

[begin proposed]

Guideline 2.5 Help users avoid mistakes and make it easy to correct them. -- OR -- Provide methods to minimize error and allow easy recovery. [level 2 guideline]

[end proposed]

[Issue #639]

[begin current]

Methods are provided to minimize error and provide graceful recovery.

[end current]

Level 1 Success Criteria for Guideline 2.5

No level 1 success criteria for this guideline

Level 2 Success Criteria for Guideline 2.5

Editorial Note: The CKW proposal suggested that this success criterion be combined with one of the (now level 3) items and that another level 2 item be moved up. [I#440]

[begin proposed] information that is given to users about mistakes or problems conforms to these guidelines. [Issue #640] [X] [end proposed]

[begin current] if an error is detected, feedback is provided to the user identifying the error (in an accessible form that meets Level A of the guidelines). [X] [end current]

Level 3 Success Criteria for Guideline 2.5

[begin proposed] users are allowed to select from a list of options as well as to enter text directly. [Issue #641] [Y] [end proposed]

[begin current] where possible, the user is allowed to select from a list of options as well as to generate input text directly [Y] [end current]

Editorial Note: NRT (5 Nov 2003): "where possible" is not testable. This is not applicable in all cases. It should be covered in some non-normative document but not here. (Untestable Success Criteria)
[begin proposed] errors are described and instructions or suggestions for correction are provided. [Issue #642] [Y] [end proposed]

[begin current] errors are identified specifically and suggestions for correction are provided where possible [Y] [end current]

Editorial Note: NRT (5 Nov 2003): "where possible" is not testable. (Untestable Success Criteria)
checks for misspelled words are applied and correct spellings are suggested when text entry is required. [Y]
where consequences are significant and time-response is not important, one of the following is true [Issue #643] [Y]

Editorial Note: NRT (5 Nov 2003): "significant" and "important" are not testable. (Untestable Success Criteria)
1. actions are reversible
2. [begin proposed]
  where actions are not reversible, they are checked for errors before going on to the next step in a process
  [end proposed]
  
  [begin current]
  where not reversible, actions are checked for errors in advance
  [end current]
3. [begin proposed]
  where actions are not reversible, and cannot be checked in advance, the user is able to review and confirm or correct information before submitting it
  [end proposed]
  
  [begin current]
  where not reversible, and not checkable, a confirmation is asked before acceptance
  [end current]

Guideline 2.5 (minimize-error) Issues

Who Benefits from Guideline 2.5 (Informative)

Individuals with writing disabilities and people with dyslexia often have difficulty writing text in forms or other places that need text input.
Individuals with speech disabilities might not be recognized properly in voice input applications.

Examples of Guideline 2.5 (Informative)

Example 1: a search engine.

A search engine is provided with a variety of search options for different skill levels and preferences. It includes a spell checker and offers "best guess" alternatives, query-by-example searches, and similarity searches.

[begin proposed]

Principle 3: UNDERSTANDABLE. Content and controls should be understandable to as many users as possible.

[end proposed]

[Issue #644]

[begin current]

Principle 3: UNDERSTANDABLE. Make content and controls understandable to as many users as possible.

[end current]

[begin proposed]

Guideline 3.1 Make it possible for automated devices to identify languages used in the content.

[end proposed]

[begin current]

Language of content can be programmatically determined.

[end current]

Level 1 Success Criteria for Guideline 3.1

[begin proposed] the natural language of the document as a whole can be identified by automated tools, including assistive technology. [Issue #646] [X] [end proposed]

[begin current] document attributes identify the natural language of the document. [X] [end current]
[begin proposed] In text documents, the language of any passage or phrase that is not written in the primary natural language of the document can be identified by automated tools, including assistive technology. [Issue #645] [X] [end proposed]

[begin current] passages or fragments of text occurring within the content that are written in a language other than the primary natural language of the content as a whole, are identified, including specification of the language of the passage or fragment. [X] [end current]
Exception:
1. The requirement above does not apply to foreign words or phrases that are found in unabridged dictionaries for the natural language of the content.
2. This success criterion does not apply to imaginary words, dialect abbreviations, or other words that are not found in unabridged Dictionaries of the primary natural language in which the document is written.
[begin current]
Note:
1. Foreign words or phrases that are found in standard unabridged dictionaries for the natural language of the content do not need to be marked.
2. This success criterion applies only to foreign words, not to imaginary words, dialect abbreviations and other words that may not be found in an unabridged dictionary of the primary language but that are not foreign words.
[end current]

Level 2 Success Criteria for Guideline 3.1

No level 2 success criteria for this guideline.

Level 3 Success Criteria for Guideline 3.1

No level 3 success criteria for this guideline.

Guideline 3.1 (language) Issues

Who Benefits from Guideline 3.1 (Informative)

Phrases from various languages are often interspersed in writing. When these phrases are identified, a speech synthesizer can voice text with the appropriate accent and pronunciation. When they are not identified, the speech synthesizer will use the default accent and pronunciation of the language on the rest of the page, which can make the phrase unintelligible. Identifying changes in language will also allow a tool to ask for automatic translations of that content. When editing content, authoring tools can switch between appropriate spelling dictionaries.

Examples of Guideline 3.1 (Informative)

Example 1: a French phrase in an English sentence.

In the following sentence, "And with a certain je ne sais quoi, she entered both the room, and his life, forever." the French phrase "je ne sais quoi" is marked as French. Depending on the markup language, English may either be marked as the language for the entire document except where specified, or marked at the paragraph level.

[begin proposed]

Guideline 3.2 The complete wording of abbreviations and acronyms can be unambiguously (clearly) determined -- OR -- Definitions of abbreviations and acronyms must be unambiguously determinable through complete wording [level 2 guideline]

[end proposed]

[Issue #347]

[begin current]

The definition of abbreviations and acronyms can be unambiguously determined.

[end current]

Level 1 Success Criteria for Guideline 3.2

No level 1 success criteria for this guideline

Level 2 Success Criteria for Guideline 3.2

Editorial Note: The CKW reorganization suggested that this guideline be combined with guideline 1.4. [I#442]

[begin proposed] acronyms and abbreviations do not appear first in standard unabridged dictionaries for the language or define the first time the first time they appear or are available in a glossary on the site. [Issue #330] [X] [end proposed]

Editorial Note: NRT (5 Nov 2003): "first in standard unabridged dictionary" is not testable. Good example is "ATM" - automatic teller machine, asynchronous transfer mode, etc. Does "first time" mean first time on the page, on a site, in the content management system, etc. ? (Untestable Success Criteria)

Editorial Note: If a standard format for doing it can be achieved, we might require that linkages to glossaries for all abbreviations and acronyms that are created by the author or site be provided. We could also recommend that linkages to any abbreviations, acronyms, etc. used by the authors also be provided. We could also have a weaker recommendation for acronyms and abbreviations appearing on the site that linkages to glossaries explaining all abbreviations acronyms, etc. that appear in any documents on the site be provided.

Level 3 Success Criteria for Guideline 3.2

a list is provided on the page or home page of URIs to cascading dictionaries that can or should be used to define abbreviations or acronyms. [Y]

Editorial Note: NRT (5 Nov 2003): "can or should be used" is not testable. Define "cascading dictionaries". Can test if there is a list of links. (Untestable Success Criteria)
the content has been reviewed, taking into account the following strategies for determining the definition of abbreviations and acronyms, applying them as appropriate. [Y]

Editorial Note: NRT (5 Nov 2003): "has been reviewed" is only testable by someone internal to the development organization. "as appropriate" is not testable. (Untestable Success Criteria)
1. provide a definition or link (with the first occurrence) of phrases, words, acronyms, and abbreviations specific to a particular community.
2. provide a summary for relationships that may not be obvious from analyzing the structure of a table but that may be apparent in a visual rendering of the table.
  
  Editorial Note: NRT (5 Nov 2003): "obvious" and "apparent" are not testable. (Untestable Success Criteria)
3. if contracted forms of words are used such that they are ambiguous, provide semantic markup to make words unique and interpretable.
  
  Editorial Note: NRT (5 Nov 2003): "ambiguous" and "interpretable" are not testable. "unique" has to have scope to be testable. (Untestable Success Criteria)

Guideline 3.2 (acronym-abbr-def) Issues

Who Benefits from Guideline 3.2 (Informative)

Defining key terms and specialized language will help people who are not familiar with the topic.
Providing the expansion of abbreviations and acronyms not only helps people who are not familiar with the abbreviation or acronym but can clarify which meaning of an abbreviation or acronym is appropriate to use. For example, the acronym "ADA" stands for both the American with Disabilities Act as well as the American Dental Association.

[begin proposed]

Guideline 3.3 Use the clearest wording that is consistent with the purpose of the content. Provide summaries or paraphrases of complex material, and provide visual or auditory illustrations as appropriate -- OR -- Design content that is no more complex than necessary and/or is supplemented with simpler forms of the content [level 2 guideline]

[end proposed]

[Issue #648]

[begin current]

Content is no more complex than is necessary and/or is supplemented with simpler forms of the content.

[end current]

Level 1 Success Criteria for Guideline 3.3

No level 1 success criteria for this guideline

Level 2 Success Criteria for Guideline 3.3

the content has been reviewed, taking into account the following strategies for evaluating the complexity of the content, applying them as appropriate. [Issue #649] [Y]

Editorial Note: NRT (5 Nov 2003): "has been reviewed" is only testable by someone internal to the development organization. (Untestable Success Criteria)
1. [begin proposed]
  The resource uses vocabulary which is widely used by members of the intended audience.
  [end proposed]
  
  [begin current]
  familiarity of terms and language structure
  [end current]
2. [begin proposed]
  The length and complexity of sentences are consistent with recommended best practices for the intended audience, such as those found in current textbooks about writing in the audience's field or discipline.
  [end proposed]
  
  [begin current]
  reasonableness of length and complexity of sentences
  [end current]
3. [begin proposed]
  Paragraphs develop a single topic or subtopic.
  [end proposed]
  
  [begin current]
  coherence of paragraphs (and sensibility in length)
  [end current]
4. [begin proposed]
  Section headings and linked text are understandable when read by themselves (for example, in a screen reader's list of links or a table of contents).
  [end proposed]
  
  [begin current]
  clarity of headings and linked text when read out of context
  [end current]
5. [begin proposed]
  Page titles are informative and unique.
  [end proposed]
  
  [begin current]
  accuracy and uniqueness of page titles
  [end current]
6. [begin proposed]
  The document uses page design, graphics, color, fonts, animations, video, or audio to clarify complex text as necessary.
  [end proposed]
  
  [begin current]
  care in the use of all-capital letters where normal sentence case might increase comprehension
  [end current]
7. [begin current]
  inclusion of non-text content to supplement text for key pages or sections of the site where they felt it was appropriate.
  [end current]

Level 3 Success Criteria for Guideline 3.3

the content has been reviewed, taking into account the strategies for evaluating the complexity of content, applying them as appropriate. [Y]

Editorial Note: NRT (5 Nov 2003): "has been reviewed" is only testable by someone internal to the development organization. (Untestable Success Criteria)

Guideline 3.3 (content-complexity) Issues

Who Benefits from Guideline 3.3 (Informative)

All users, especially those with cognitive, learning, and/or reading disabilities benefit from the use of clear and simple writing. This should not discourage you from expressing complex or technical ideas.
Using clear and simple language also benefits people whose first language differs from your own, including those people who communicate primarily in sign language.
Sounds, graphics, videos and animations can help make concepts presented in a Web site easier to understand, especially for people with cognitive, reading, or learning disabilities or those who are unfamiliar with the language of the text of the site.
Summarizing information that is difficult to understand helps people who do not read well.
Providing a summary of the visual cues that show relationships between complex information helps people who do not use visual cues or who have difficulty using visual cues. For example, people who are completely blind do not use any visual cues, while people with dyslexia or with low vision might have difficulty interpreting visual cues.

Note:

Designers need to be cautious in deciding when to use illustrations. Reading a picture is probably a learned activity that is easier for some than others. Some users skip the pictures; others read only the pictures. Designers must also recognize that visual conventions are not universal and that individuals develop their own mental schema and expectations in interpreting visual information.

Examples of Guideline 3.3 (Informative)

Example 1: a description of a process.

A page describes how to learn to play soccer. Each step in learning the fundamentals of the game is illustrated with a photograph of a player doing what is described in the text.
Example 2: a concrete concept.

The primary concept on a page is concrete. It is discussing Mt. Pinatubo. It includes both a description of the 1991 eruption as well as photos of the eruption and the aftermath. It links to another site that contains video and another site that contains a 3D simulation of what happened underneath the crust and within the volcano during the eruption.
Example 3: child's report of school trip.

A child went with her school on a trip to a bicycle manufacturing plant. She wrote a report for her family and friends to post to the Web. In the report, she includes the company logo as well as a picture of a bicycle on the assembly line. She links to the company Web site for more information. She includes photos she took of the plant.
Example 4: stock trading data.

A news site is comparing the performance of the economy from 3rd quarter of this year with 3rd quarter from the last 3 years. They compare prices of the most popular stocks. They present the data in a bar graph with a link to the raw data they used to create the bar graph.
Example 5: history of music.

A grandfather's hobby is listening to and playing music. He creates a Web site that includes examples of many different types of music and musical instruments. When describing specific types of music, he links to a short sound clip.

[begin proposed]

Guideline 3.4 Use consistent layout and make the behavior of interactive elements predictable -- OR -- Make layout and behavior of content consistent and/or predictable [level 2 guideline]

[end proposed]

[begin current]

Layout and behavior of content is consistent or predictable, but not identical.

[end current]

Level 1 Success Criteria for Guideline 3.4

No level 1 success criteria for this guideline

Level 2 Success Criteria for Guideline 3.4

key orientation and navigational elements (such as navigation bars) are generally found in one or two consistent locations or their locations are otherwise predictable. [Y]

Editorial Note: NRT (5 Nov 2003): "key", "generally", and "predictable" are not testable. (Untestable Success Criteria)
where inconsistent or unpredictable responses are essential to the function of the content (e.g. mystery games, adventure games, tests, etc.) the user is warned in advance of encountering them. [Y]

Editorial Note: NRT (5 Nov 2003): "inconsistent" and "unpredictable" are not testable. (Untestable Success Criteria)
wherever there are extreme changes in context, one of the following is true: [Y]
1. an easy to find setting, that persists for the site visit, is provided for the user to deactivate processes or features that cause extreme changes in context or
2. extreme changes in context are identified before they occur so the user can determine if they wish to proceed or so they can be prepared for the change
Editorial Note: NRT (5 Nov 2003): Might be able to make this testable if we come up with a better definition of "extreme changes in context" (Untestable Success Criteria)

Level 3 Success Criteria for Guideline 3.4

[begin proposed] user can select a different location for navigation elements in the layout of the page. [Issue #352] [Y] [end proposed]
the content has been reviewed, taking into account common ideas for making content consistent and predictable, applying them as appropriate. [Y]

Editorial Note: NRT (5 Nov 2003): "has been reviewed" is only testable by someone internal to the development organization. (Untestable Success Criteria)

Guideline 3.4 (consistent-behavior) Issues

Who Benefits from Guideline 3.4 (Informative)

Providing consistent and predictable responses to user actions is important feedback for the user. This lets them know that your site is working properly and encourages them to continue interacting with the content. When users receive an unexpected response, they might conclude that something is wrong or broken. Some people might become so confused they will not be able to use your site.
Individuals who are unable to detect extreme changes in context or may not realize that the context has changed are less likely to become disoriented while navigating a site. This applies to people in the following ways:
- Individuals who are blind or have low vision may have difficulty knowing when a visual context change, such as a new window popping up, has occurred. In this case, warning users of context changes in advance minimizes confusion when the user discovers that the back button no longer behaves as expected.
- Using captions to note changes in speaker is beneficial for individuals who are deaf or hard of hearing and who may be unable to discern changes in speaker for audio-only presentations.
Some individuals with low vision, with dyslexia and who have difficulty interpreting visual cues may benefit from additional cues in order to detect extreme changes in context.

Examples of Guideline 3.4 (Informative)

Example 1: a form to deactivate pop-up windows.

A checkbox is provided on a page of links to let the user select whether they want the resultant pages to appear in new windows or not.
Example 2: a warning given before a pop-up window.

At the end of a news story, several links are provided for more information. At the beginning of each link is an icon of an arrow with the text equivalent, "Link will open in new window."
Example 3: frames that do not track history making the back button behave unexpectedly.
Example 4: forms.

Editorial Note: Some of these examples are very brief. Should they be expanded and clarified with further details?

Principle 4: ROBUST. Use Web technologies that maximize the ability of the content to work with current and future accessibility technologies and user agents.

Guideline 4.1 Use technologies according to specification.

Level 1 Success Criteria for Guideline 4.1

except where the site has documented that a specification was violated for backward compatibility or compatibility with assistive technology, the technology has: [X]
1. passed validity tests for the version of the technology in use (whether it be conforming to a schema, Document Type Definition (DTD), or other tests described in the specification)
2. structural elements and attributes are used as defined in the specification

Level 2 Success Criteria for Guideline 4.1

No level 2 success criteria for this guideline.

Level 3 Success Criteria for Guideline 4.1

technologies are used according to specification without exception. [Y]

Guideline 4.1 (use-spec) Issues

Who Benefits from Guideline 4.1 (Informative)

This guideline further emphasizes that following specifications increases the likelihood of accessible content. While other guidelines refer to individual pieces of content, this guideline takes a step back to look at the broad picture. It also exists to help cover future technologies or issues that we did not anticipate at the time of writing this guideline. Thus, the benefits of following specifications are primarily that assistive technologies and user agents can render the content according to spec.
Following specifications for markup and other file formats makes it possible to more easily reformat, repurpose and reuse content, which is important to users who can only make full use of content when presented in a particular format.

Examples of Guideline 4.1 (Informative)

Example 1: structural elements.

Throughout a historical Web site, structural elements are used appropriately to indicate the presence of quotations, definitions and bibliographic references. Because these elements have (only) been used according to specification, user agents can be configured so that these elements are differentiated from the rest of the content, allowing an end user to optimize her use of the site for research purposes.
Example 2: presentation elements.

A Web author wishes to focus attention on a series of words on a page for purely artistic reasons. He uses elements designed for applying stylistic and presentation characteristics, rather than elements that are designed to convey information about the structure or organization of a page, to enhance the visual presentation and avoids implying unintended meaning about page organization for non-visual or text-only users.
Example 3: accessible APIs.

A Java applet uses the accessibility API defined by the language. Refer to the IBM Guidelines for Writing Accessible Applications Using 100% Pure Java.

Guideline 4.2 Ensure that user interfaces are accessible or provide an accessible alternative(s)

Level 1 Success Criteria for Guideline 4.2

at least one plug-in required to access the content conform to at least the default set of conformance requirements of the User Agent Accessibility Guidelines (UAAG) 1.0 at Level A plus the sets of requirements (a) through (j) (below) that apply. If required plug-ins are not accessible, an alternative solution is provided that conforms to WCAG 2.0. If inaccessible plug-ins are available, then a method for obtaining an accessible plug-in is provided from the content. [Y]
any programmatic user interface components of the content conform to at least the default set of conformance requirements of the UAAG 1.0 at Level A plus the sets of requirements (a) through (j) (below) that apply. If the custom user interfaces cannot be made accessible, an alternative solution is provided that meets WCAG 2.0 (including this provision) to the level claimed. [Y]
Requirements (a) through (j)
1. If the application renders visual text, it should conform to the VisualText checkpoints.
2. If the application renders images, it should conform to the Image checkpoints.
3. If the application renders animations, it should conform to the Animation checkpoints.
4. If the application renders video, it should conform to the Video checkpoints.
5. If the application renders audio, it should conform to the Audio checkpoints.
6. If the application performs its own event handling, it should conform to the Events checkpoints.
7. If the application implements a selection mechanism, it should conform to the Selection checkpoints.
8. The application should support keyboard access per UAAG 1.0 checkpoints 1.1 and 6.7.
9. If the application implements voice or pointer input, it should conform to the Input Modality checkpoints.
10. accessibility conventions of the markup or programming language (API's or specific markup) are used (@@in UAAG somewhere?)

Level 2 Success Criteria for Guideline 4.2

No level 2 success criteria for this guideline.

Level 3 Success Criteria for Guideline 4.2

the Web resource includes a list of the technologies user agents must support in order for its content to work as intended. The list is documented in metadata if such metadata is supported by the format, otherwise is documented in a policy statement associated with the content. [Y]
Users who do not have one or more of these technologies can still access and use the resource, though the experience may be degraded. [Y]

Note:

When selecting required technologies, consider that assistive hardware and software is often slow to adapt to technological advances, and the availability of assistive technology varies across natural languages. Verify that assistive technology compatible with the technologies you choose is available in the natural language(s) of your content.
Technologies and features on the required list are open standards or have a public specification. [Y]

Guideline 4.2 (technology-supports-access) Issues

Who Benefits from Guideline 4.2 (Informative)

Authors who ensure the accessibility of user interfaces within their content will:
- encounter fewer challenges when implementing these guidelines
- avoid the need to create custom solutions and workarounds to address accessibility concerns
- avoid the need to provide accessible alternate versions for content rendered in a technology that does not fully address these guidelines
Benefits of determining and documenting technology requirements:
- Individuals can identify (either through site documentation or automatically through metadata) whether or not they are likely to be able to use a site. In conjunction with a search engine or a proxy server, this could be used to automatically filter out sites a user can not access or to automatically filter to the top sites that would be most usable.
- Documenting technology requirements will cause authors to evaluate assumptions about user agents and will minimize the number of sites that are inadvertently inaccessible because they are unaware of backward compatibility issues.
Benefits of ensuring user interface accessibility and providing accessible alternatives:
- Individuals who must use alternative browsing technologies and devices will be able to access the content.
- Individuals who can not afford or otherwise do not have access to newer technologies also benefit from backward compatibility in that they will not need to purchase upgrades or equipment as often.

Examples of Guideline 4.2 (Informative)

Example 1: an online store that lists required technologies.

By documenting minimum user agent requirements, the store makes it possible for people using particular technologies to determine whether they are going to have trouble using the store or its checkout mechanism before they begin shopping. This prevents users from finding that, after they have selected their products and initiated a checkout process, finding out that they are unable to complete their transaction. They can, therefore, choose alternatives where they can be assured greater success.
Example 2: an intranet site that transforms gracefully.

A large company was concerned about the ability to address individuals at many diverse office locations that have different technology bases. To address the problem, the created two versions of their content and documented the requirements for each, making it easy for individual locations to determine which version would work best for their technologies.
Example 3: an informational site ensuring backward compatibility.

An information site covers a wide variety of subjects and wants to enable their visitors to quickly find the topics they're looking for. To do this, they have implemented an interactive menu system that is only supported in the most recent version of two popular user agents. To ensure that their visitors who do not use these specific user agents are still able to effectively use the site, a navigation mechanism that does not depend on the interactive menu system they are using is presented to user agents that do not support the newer technology.

Appendix A Glossary

Editorial Note: The WCAG WG has not tackled the definitions of the terms that we are using and acknowledges that we sometimes use terms inconsistently. We need to coordinate our terms and definitions with the WAI Glossary and are working on proposals for a variety of definitions. We have been looking at the UAAG 1.0 glossary and other glossaries within the W3C.

[begin del] ability to be expressed in words

content that can be expressed accurately and unambiguously in a reasonable number of words (for example, diagrams, charts, illustrations, etc.) Content such as a musical performance or visual artwork is considered "content that can not be expressed in words," since this type of content relies heavily on the visual (or auditory) experience.[I#320]

Editorial Note: the proposed wording in guideline 2.1 no longer references this definition.

[end del]

audio description

An audio description is a verbal description of all significant visual information in scenes, actions, and events that cannot be perceived from the sound track alone to the extent possible given the constraints posed by the existing audio track and limitations on freezing the audio visual program to insert additional auditory description.

Note:

When adding audio description to existing materials, the amount of information conveyed through audio description is constrained by the amount of space available in the existing audio track unless the audio/video program is periodically frozen to insert audio description. However, it is often impossible or inappropriate to freeze the audio/visual program to insert additional audio description.

audio descriptions

Audio descriptions are equivalents of visual information from actions, body language, graphics, and scene changes that are voiced (either by a human or a speech synthesizer) and synchronized with the multimedia presentation.

captions

Captions are text equivalents of auditory information from speech, sound effects, and ambient sounds that are synchronized with the multimedia presentation.

competitive activity

A competitive activity is an activity where timing is an essential part of the design of the activity. Removal of the time element would change the performance of the participants. Versions of the activity (e.g. test) that have no time basis or time limits might be preferred and may be required for some venues but this would require a complete redesign of the activity (e.g. test) and may change the character and validation methodology and would therefore not fall under these guidelines.

complex content

Content is considered complex if the relationships between pieces of information are not easy to figure out. If the presentation of the information is intended to highlight trends or relationships between concepts, these should be explicitly stated in the summary.

Examples of complex information:

data tables,
concepts that are esoteric or difficult to understand,
content that involves several layers.

content

Content

Editorial Note: We need to include a definition for content here.

content that blinks

Content that blinks is content that turns on and off between .5 and 4 times per second.

controlled languages

Controlled languages use a restricted vocabulary taken from natural language. The purpose is to make texts easier to understand and translate. Standards generally limit words to a single meaning and prescribed part of speech. Complex syntax is avoided. Information about controlled language applications is available on the World Wide Web.

event handler

A section of code that responds to an action taken by the user (or user agent). On Web pages, events are usually user actions such as moving the mouse, typing, etc. An event handler determines the response to that action. A technology specific event handler only responds to an action by one kind of input device. An abstract event handler is one which can be activated by a variety of input devices.

feature

A feature is a specific component of a technology, for example an element in a markup language or a function call in an Application Programming Interface. Typically, a given feature may only be available in specific versions of the technology, and thus may need to be noted explicitly in the required list.

functionality

Functionality is the purpose or intended effect of the content. This may include presentation of information , data collection, securing a response from the user, providing user experience, linking to other content, testing, confirmation, purchasing, etc.

keyboard interface

On devices that do not have a built-in or attached keyboard, there is often an alternate method for connecting a keyboard to the device for the purpose of generating text or an internal method for generating text. Allowing control via the "keyboard interface" means that the content could be controlled through commands issued from the keyboard or by alternate methods that are capable of generating text as if a keyboard had been used.

mechanisms that cause extreme changes in context

Mechanisms that cause extreme changes in context include:

opening a new browser window unexpectedly and without any nonvisual cue (back button suddenly appears nonfunctional)
in an auditory presentation, the speaker changes with no visual cue and no notation in captions
captions that do not identify a change in speaker

Common user actions include:

mouse movements
key activation
link selection
use of browser navigation buttons (e.g. back and forward)
opening new browser windows

Common responses to user actions include:

loading a new page
exposing/concealing content based on mouse position or keyboard focus
displaying the contents of a menu (auditorily or visually)
displaying pop-up menus or windows
submitting a form

It is important that responses to user actions be predictable and sensible to the end user and that interactions are consistent, both throughout the site and with commonly used interaction metaphors used throughout the Web.

media equivalents

Media equivalents present essential audio information visually (captions) and essential video information auditorily (audio descriptions).

natural languages

Natural languages are those used by humans to communicate, including spoken, written, and signed languages.

non-text content

non-text content includes but is not limited to images, text in raster images, image map regions, animations (e.g., animated GIFs), ASCII art, 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.

Note:

Scripts, applets, and programmatic objects are not covered in this definition and are addressed in guideline 4.3.

presentation

Presentation is the rendering of the content and structure in a form that can be sensed by the user.

programmatic user interface component

An interface component created by the author that is in addition to those provided by the user agent. For example, an HTML checkbox would not be a programmatic user interface component because the author is using an interface component supported by the user agent. A checkbox function implemented in script, however, would be a programmatic user interface component because it provides functionality that is not known or supported by user agents and can not be made accessible by user agents even if the user agent complied with UAAG.

real-time events

Real-time events are those that are based on the occurrence of events in real-time where the events are not under the control of the author.

site navigation mechanism

A site navigation mechanism is a mechanism for easily orienting and moving about within the site. Site navigation mechanisms include but are not limited to:

A home page with hyperlinks on it and subsequent pages that link to the other pages at the site
site map(s)
search engine(s)
expanding outline(s)
dynamic fisheye views showing all linked pages or topics related to any page.
3-D virtual representations of site content

structure

Structure includes both hierarchical structure of the content and non-hierarchical relationships such as cross-references, or the correspondence between header and data cells in a table.The heirarchical structure of content represents changes in context. For example,

A book is divided into chapters, paragraphs, lists, etc. Chapter titles help the reader anticipate the meaning of the following paragraphs. Lists clearly indicate separate, yet related ideas. All of these divisions help the reader anticipate changes in context.
A bicycle is divided into wheels and a frame. Further, a wheel is divided into a tire and a rim. In an image of the bicycle, one group of circles and lines becomes "wheel" while another group becomes "frame."

technology

A technology is a

markup or programming language
application Programming Interface (API)
or communication protocol

text equivalent

A text equivalent

serves the same function as the non-text content was intended to serve.
communicates the same information as the non-text content was intended to convey.
may contain structured content or metadata.

Note:

Text-equivalents should be easily convertible to braille or speech, displayed in a larger font or different colors, fed to language translators or abstracting software, etc.

time-dependent presentation

A time-dependent presentation is a presentation that

is composed of synchronized audio and visual tracks (e.g., a movie), OR
requires the user to respond interactively at specific times in the presentation.

unfamiliar content

Content might be unfamiliar if you are using terms specific to a particular community. For example, many of the terms used in this document are specific to the disability community.

Appendix B Contributors

Participants in the WCAG Working Group

Appendix C The differences between WCAG 1.0 and WCAG 2.0

Since the release of WCAG 1.0 in May 1999, the WCAG Working Group has received feedback on priorities of checkpoints, the usability of the set of documents, and requests for clarifications on the meaning of specific checkpoints and what is needed to satisfy them. Thus, it is intended that WCAG 2.0, when it eventually becomes a W3C Recommendation:

will be more efficiently organized,
may adjust the priority of some checkpoints,
may modify, remove, or add requirements due to changes in Web technologies since the publication of WCAG 1.0,
will incorporate the Errata from WCAG 1.0,
will reflect the experience gained in implementing WCAG 1.0.

For a detailed comparison, refer to the Mapping Between WCAG 1.0 and the WCAG 2.0 Working Draft.

Improvements in WCAG 2.0

We hope that WCAG 2.0 will have several improvements over WCAG 1.0. While the primary goal of WCAG 2.0 is the same as WCAG 1.0 (to promote accessibility of Web content) additional goals for WCAG 2.0 include improvements that will:

Ensure that requirements may be applied across technologies
Ensure that the conformance requirements are clear
Ensure that the deliverables are easy to use
Write to a more diverse audience
Clearly identify who benefits from accessible content
Ensure that the revision is "backward compatible" with WCAG 1.0

For more information about the intended improvements in WCAG 2.0 Working Draft, please refer to Requirements for WCAG 2.0.

Appendix D References

Editorial Note: Links within the document will be turned into references and the links to those documents will be listed here. They are inline for the time being.

Appendix E Additional Notes

Editorial Note: The following items are the additional notes from previous drafts. They are referenced from level 3 sections of some guidelines but there is not yet consensus on whether these items should be removed from the document or how they might be incorporated into other documents.

[begin proposed]

Strategies for reducing complexity include, but are not limited to:

Editorial Note: The proposed edits in the plain language proposal (Issue 650) for this section involved a complete reorganization of this section. Therefore, individual edits have not been tracked.

E.1.1 In general

Organize material so it is easy to read and use.
Use a style manual, dictionary, and other reference materials.
Test documents to learn if potential users understand the material, and include people with cognitive, learning, or reading disabilities in the test group.

E.1.2 Vocabulary

Use vocabulary that will be familiar to intended readers.
- If the resource is intended for people who work in a particular technical field, consider using a Controlled Language. For example, a resource designed for aircraft engineers could use a controlled language like the one used by Boeing Aircraft Company.
- If a technical resource is intended for translation into other languages, consider using a Controlled Language.
- If the resource is intended for a general audience or for translation into other languages, avoid professional jargon, slang, and other terms with a specialized meaning that may not be clear to people outside a specific group. Review the document for plain language, using a checklist like the ones produced by US and Canadian government agencies.
Editorial Note: js: We should include examples from other countries and other languages if possible
If the resource is intended for a general audience and it is necessary to use words that have specialized meanings, define those words.
When there is a choice between abstract and concrete terms, use the more concrete term unless there is a specific reason for using the abstract term.
Avoid ambiguity unless it is an essential aspect of the subject-matter.

E.1.3 Sentences

Make sentence-length consistent with common practice in the language of the document or the primary audience for whom the document is intended. Consult textbooks about writing in that field or discipline.

E.1.4 Syntax

Use the simplest sentence forms consistent with the purpose of the content
- For example, the simplest sentence-form for English consists of Subject-Verb-Object, as in John hit the ball or The Web site conforms to WCAG 2.0.
Consider using bulleted or numbered lists in place of paragraphs that contain long series of words or phrases separated by commas

E.1.5 Nouns, noun-phrases, and pronouns

Use single nouns or short noun-phrases.
Make sure that pronoun references and references to earlier points in the document are clear
The sentence below contains several pronouns whose references are not clear:

Web developers can't understand those guidelines because they don't speak their language.
1. It is not clear which guidelines are referred to as "those guidelines" (the guidelines you are reading now would be these guidelines)
2. It isn't clear whether the pronoun "they" refers to the Web developers or to the guidelines (the rules of English syntax indicate that the reference is to the guidelines, but common usage doesn't always obey those rules)
3. It isn't clear whether the pronoun "their" refers to the language used by the Web developers or the language in which the guidelines are written.
The sentence can be rewritten to resolve the ambiguities:

Web developers can't understand these guidelines because the guidelines are not written in the developers' language.

E.1.6 Verbs

E.1.7 Voice

For documents written in English and some other Western languages, use the active voice unless there is a specific reason for using passive constructions. Sentences in the active voice are often shorter and easier to understand than those in the passive voice.
- Active: Many people believe that readers understand sentences in the active voice more easily than sentences in the passive voice.
- Passive: It is believed by many that sentences in the active voice are more easily understood by readers than sentences in the passive voice.

E.1.8 Tenses

Use verb tenses consistently.

For example, do not switch randomly between past and present tense. In the sentences, John left the room. He takes the elevator down to the lobby, the shift from past tense (in the first sentence left the room) to present tense in the second sentence (takes the elevator) might create ambiguity about John's use of the elevator: did he use it in the past or is he using it now?

E.1.9 Logic and relationships

Indicate the logical relationships between phrases, sentences, paragraphs, or sections of the text.
- In some cases, simple words such as and, however, furthermore, and therefore may be enough to make the logical relationship clear between one sentence and the next. Other cases may require longer phrases or even additional sentences.

E.1.10 Instructions and operable content

Editorial Note: js: I suggest moving the items under this heading to Guideline 2.5 (help users avoid mistakes and make it easy to correct them

Thoroughly explain instructions or required actions
Use names and labels consistently.
Clarity where the document:
- addresses users
- explains choices and options
- labels options to get more information
- instructs users how to modify selections in critical functions (such as how to delete an item from a shopping cart)
Application of:
- Use a goal-action structure for menu prompts.
- default settings (and the ease in re-establishing them)
- Use two-step, "select and confirm" processes to reduce accidental selections for critical functions
- Provide calculation assistance to reduce the need to calculate (for example, use a script to calculate the total price for an online purchase)

E.1.11 Alternative representations: summaries, paraphrases, examples, illustrations, and symbolic languages

Editorial Note: js: I propose deleting the first two items under this head, which are addressed earlier in this guideline

Provide summaries to aid understanding
add non-text content to the site for key pages or sections specifically to make the site more understandable by users who cannot understand the text only version of the site.
Make it possible to convert text into symbolic languages such as those used by Augmentative and Alternative Communication (AAC) devices

Editorial Note: js: WCAG 1.0 and Section 508 both allow text-only variants only in cases when the "original" can't be made accessible any other way, and then require that the text-only variant be updated whenver the "original" changes. That seems to have dropped out of WCAG 2.0, but I think we need to reinstate it.

Editorial Note: js: say how-through metadata? And we need an example for this one, under examples. Clearly a Level 3

[end proposed]

[begin current]

Strategies for evaluating the complexity of the content

use of sentence structures that increase understanding
- such as active voice in languages where this form helps convey information
length of noun phrases
- strings of no more than three or four nouns are easiest to understand
clarity of reference with pronouns and anaphoric expressions (these refer back to something already said in the text)
- example of potential ambiguity: "Scientists study monkeys. They eat bananas."
correct use of conjunction forms and adverbs to make explicit the relationship between phrases or parts of the text
- such as "and," "but," "furthermore," "not only"
complexity of verb tenses
- do the tenses used in a document seem overly complicated?
intelligibility of verb phrases
familiarity of idioms or slang
logic in the order and flow of information
consequences of ambiguity or abstraction
improved readability of vertical lists might offer in place of long paragraphs of information
use of summaries to aid understanding
thoroughness in the explanation of instructions or required actions
consistency in the use of names and labels
clarity where the document:
- addresses users
- explains choices and options
- labels options to get more information
- instructs users how to modify selections in critical functions (such as how to delete an item from a shopping cart)
application of:
- proper markup to highlight key information
- goal-action structure for menu prompts
- default settings (and the ease in re-establishing them)
- two-step "select and confirm" processes to reduce accidental selections for critical functions
- calculation assistance to reduce the need to calculate
testing with potential users for ease of accessibility
use of a controlled language
providing support for conversion into symbolic languages
adding non-text content to the site for key pages or sections specifically to make the site more understandable by users who cannot understand the text only version of the site.

[end current]

Common ideas for making content consistent and predictable

place navigation bars in a consistent location whenever possible
similar layout for user interface components should be used for sections or whole site
similar user interface components should be labeled with similar terminology
use headers consistently
use templates for consistent presentation of sections or whole site
pages with similar function should have similar appearance and layout
controls that look or sound the same should be designed to act the same
conventions likely to be familiar to the user should be followed
unusual user interface features or behaviors that are likely to confuse the first-time user should be described to the user before they are encountered
[begin proposed]
allow the user to select different page layout templates for presentation of pages. (e.g. 3 column, linear, adding extra orientation or navigation elements, etc.) [Issue #353]
[end proposed]

Web Content Accessibility Guidelines 2.0

W3C Working Draft 14 February 2004

Abstract

Status of this Document

Table of Contents

Appendices

Introduction

Purpose

How to read this document

1 - Top layer - Overview of Design Principles, Guidelines, Success Criteria

2 - Technology-specific Checklists

3 - Bottom layer - Technology-specific application information

Audience

Scope

Priorities and Techniques

Conformance

Conformance Claims

Sites that conform to WCAG 1.0

Overview of Design Principles

User needs

Designing Accessible Web Content

Principle 1: Content must be Perceivable.

Level 1 Success Criteria for Guideline 1.1

Level 2 Success Criteria for Guideline 1.1

Level 3 Success Criteria for Guideline 1.1

Who Benefits from Guideline 1.1 (Informative)

Examples of Guideline 1.1 (Informative)

Guideline 1.2 Provide synchronized media equivalents for time-dependent presentations.

Level 1 Success Criteria for Guideline 1.2

Level 2 Success Criteria for Guideline 1.2

Level 3 Success Criteria for Guideline 1.2

Who Benefits from Guideline 1.2 (Informative)

Examples of Guideline 1.2 (Informative)

Guideline 1.3 Make information, structure, and functionality recognizable even when users or user agents change the presentation format. -- OR -- Preserve information, structure, and functionality when changing visual or auditory presentation format.

Level 1 Success Criteria for Guideline 1.3

Level 2 Success Criteria for Guideline 1.3

Level 3 Success Criteria for Guideline 1.3

Who Benefits from Guideline 1.3 (Informative)

Examples of Guideline 1.3 (Informative)

Guideline 1.4 For text, use fonts that can be represented in Unicode.

Level 1 Success Criteria for Guideline 1.4

Level 2 Success Criteria for Guideline 1.4

Level 3 Success Criteria for Guideline 1.4

Who Benefits from Guideline 1.4 (Informative)

Examples of Guideline 1.4 (Informative)

Guideline 1.5 Make structure perceivable -- OR -- Make structure perceivable through presentation [level 2 guideline]

Level 1 Success Criteria for Guideline 1.5

Level 2 Success Criteria for Guideline 1.5

Level 3 Success Criteria for Guideline 1.5

Who Benefits from Guideline 1.5 (Informative)

Examples of Guideline 1.5 (Informative)

Guideline 1.6 In visual presentations, make it easy to distinguish foreground words and images from the background.

Level 1 Success Criteria for Guideline 1.6

Level 2 Success Criteria for Guideline 1.6

Level 3 Success Criteria for Guideline 1.6

Who Benefits from Guideline 1.6 (Informative)

Examples of Guideline 1.6 (Informative)

Guideline 1.7 In default auditory presentations, make it easy to distinguish foreground speech and sounds from background sounds. [level 2 guideline]

Level 1 Success Criteria for Guideline 1.7

Level 2 Success Criteria for Guideline 1.7

Level 3 Success Criteria for Guideline 1.7

Who Benefits from Guideline 1.7 (Informative)

Examples of Guideline 1.7 (Informative)

Principle 2: OPERABLE. Any user should be able to operate all Interface Elements that are part of the content

Guideline 2.1 Make all functionality operable via a keyboard or a keyboard interface.

Level 1 Success Criteria for Guideline 2.1

Level 2 Success Criteria for Guideline 2.1

Level 3 Success Criteria for Guideline 2.1

Who Benefits from Guideline 2.1 (Informative)

Examples of Guideline 2.1 (Informative)

Guideline 2.2 Allow users to control time limits on their reading or interaction unless specific real-time events or rules of competition make such control impossible.

Level 1 Success Criteria for Guideline 2.2

Level 2 Success Criteria for Guideline 2.2

Level 3 Success Criteria for Guideline 2.2

Who Benefits from Guideline 2.2 (Informative)

Examples of Guideline 2.2 (Informative)

Guideline 2.3 Allow users to avoid content that is designed to flicker.

Level 1 Success Criteria for Guideline 2.3

Level 2 Success Criteria for Guideline 2.3

Level 3 Success Criteria for Guideline 2.3