Understanding WCAG 2.0

Intent of Guideline 1.1

The purpose of this guideline is to ensure that all non-text content is also available in text form. "Text form" refers to electronic text, not an image of text. Electronic text has the unique advantage that it can be rendered visually, auditorily, tactilely, or by any combination. As a result, information rendered in electronic text can be presented in whatever form best meets the needs of the user. It can also be easily enlarged, spoken in a voice that is easy to understand or rendered in whatever tactile form best meets the needs of a user.

Intent of this Success Criterion

The intent of this success criterion is to make information conveyed by non-text content accessible through the use of a text alternative. Text alternatives are a primary way for making information accessible because they can be rendered through any sensory modality (for example, visual, auditory or tactile) to match the needs of the user. Providing text alternatives allows the information to be rendered in a variety of ways by a variety of user agents. For example, a person who cannot see a picture can have the text alternative read aloud using synthesized speech. A person who cannot hear an audio file can have the text alternative displayed so that he or she can read it. In the future, text alternatives will also allow information to be more easily translated into sign language or into a simpler form of the same language.

Techniques for Addressing Success Criterion 1.1.1

Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this criterion. The techniques listed only satisfy the success criterion if all of the WCAG 2.0 conformance requirements have been met.

Examples of Success Criterion 1.1.1

1. A data chart

   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, provides a high-level summary of the data , trends and implications comparable to those available from the chart. Where possible and practical, the actual data is provided in a table. [LC-789]

2. An audio recording of a speech (no video)

   The link to an audio clip says, "Chairman's speech to the assembly." A link to a text transcript is provided immediately after the link to the audio clip.

3. An animation that illustrates how a car engine works

   An animation shows how a car engine works. There is no audio and the animation is part of a tutorial that describes how an engine works. Since the text of the tutorial already provides a full explanation, the text alternative has a brief description of the image and refers to the tutorial text for more information. [LC-1074]

4. A traffic Web camera

   A Web site allows users to select from a variety of Web cameras positioned throughout a major city. After a camera is selected, the image updates every two minutes. A short text alternative identifies the Web camera as "traffic Web camera." The site also provides a table of travel times for each of the routes covered by the Web cameras. The table is also updated every two minutes.

5. A photograph of an historic event in a news story

   A photograph of two world leaders shaking hands accompanies a news story about an international summit meeting. The text alternative says, "President X of Country X shakes hands with Prime Minister Y of country Y."

6. A photograph of a historic event in content discussing diplomatic relationships

   The same image is used in a different context intended to explain nuances in diplomatic encounters. The image of the president shaking hands with the prime minister appears on a Web site discussing intricate diplomatic relationships. The first text alternative reads, "President X of country X shakes hands with Prime Minister Y of country Y on January 2, 2009." An additional text alternative describes the room where the leaders are standing as well as the expressions on the leaders' faces, and identifies the other people in the room. The additional description might be included on the same page as the photograph or in a separate file associated with the image through a link or other standard programmatic mechanism.

7. An audio recording

   The Web page described in the previous example includes a link to an audio recording of the leaders' press conference. The page also links to a text transcript of the press conference. The transcript includes a verbatim record of everything the speakers say. It identifies who is speaking as well as noting other significant sounds that are part of the recording, such as applause, laughter, questions from the audience, and so on.

8. An e-learning application

   An e-learning application uses sound effects to indicate whether or not the answers are correct. The chime sound indicates that the answer is correct and the beep sound indicates that the answer is incorrect. A text description is also included so that people who can't hear or understand the sound understand whether the answer is correct or incorrect. [LC-1326]

9. A linked thumbnail image

   A thumbnail image of the front page of a newspaper links to the home page of the "Smallville Times". The text alternative says "Smallville Times". [LC-858]

Related Resources

Resources are for information purposes only, no endorsement implied.

• Excerpts from the NBA Tape Recording Manual, Third Edition. Information on describing complex images to people who are blind.

• Inaccessibility of CAPTCHA. Examines a number of potential solutions that allow systems to test for human users while preserving access by users with disabilities. [LC-556]

Intent of Guideline 1.2

The purpose of this guideline is to provide access to multimedia. Multimedia is defined in the glossary as:

multimedia: audio or video synchronized with another type of media and/or with time-based interactive components

Note that an audio file accompanied by interaction is covered here, as is a video-only file that involves interaction. These are covered because interaction must take place at a particular time. Having a text transcript that said, "for more information, click now," would not be very helpful since the reader would have no idea when the audio said, "now." As a result, synchronized captions would be needed.

Sometimes, there is so much dialogue that audio description cannot fit into existing pauses in the dialogue. The option at Level 1 to provide a full text alternative for multimedia including any interaction instead of audio description for multimedia would allow access to all of the information in the multimedia. This option also allows access to the visual information in non-visual form when audio description is not provided for some other reason.

For multimedia that includes interaction, interactive elements (for example links) could be embedded in the full text alternative for multimedia.

This guideline also includes (at Level 3) sign language interpretation for multimedia as well as an approach called extended audio description. In extended audio description, the video is frozen periodically to allow more audio description to take place than is possible in the existing pauses in the dialogue. This is a case where higher-level success criteria build upon the requirements of lower-level SC with the intention of having cumulative, progressively stronger, requirements. [LC-1223]

Intent of this Success Criterion

The intent of this success criterion is to enable people who are deaf or hard of hearing to watch multimedia presentations. Captions provide the part of the content available via the audio track. Captions not only include dialogue, but identify who is speaking and note important sounds.

It is acknowledged that at the present time there may be difficulty in creating captions for time-sensitive material and this may result in the author being faced with the choice of delaying the information until captions are available, or publishing time-sensitive content that is inaccessible to the deaf, at least for the interval until captions are available. Over time, the tools for captioning as well as building the captioning into the delivery process can shorten or eliminate such delays. [LC-1332]

Captions are not needed when the multimedia is, itself, an alternate presentation of information that is also presented via text on the Web page. For example, if information on a page is accompanied by a multimedia presentation that is easier for people with cognitive, language, or learning disabilities to understand, then it would not need to be captioned since the information is already presented on the page in text or in text alternatives (e.g. for images). [LC-608]

Techniques for Addressing Success Criterion 1.2.1

Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this criterion. The techniques listed only satisfy the success criterion if all of the WCAG 2.0 conformance requirements have been met.

Examples of Success Criterion 1.2.1

• A captioned tutorial

  A video clip shows how to tie a knot. The captions read,

  "(music)

  Using rope to tie knots was an important skill

  for the likes of sailors, soldiers and woodsmen.."

  From Sample Transcript Formatting by Whit Anderson.

• A complex legal document contains multimedia clips for different paragraphs that show a person speaking the contents of the paragraph. Each clip is associated with its corresponding paragraph. No captions are provided for the multimedia. [LC-608]

• An instruction manual containing a description of a part and its necessary orientation is accompanied by a multimedia clip showing the part in its correct orientation. No captions are provided for the multimedia clip. [LC-608]

Related Resources

Resources are for information purposes only, no endorsement implied.

(none currently documented)

Intent of this Success Criterion

The intent of this success criterion is to provide people who are blind or visually impaired access to the visual information in a multimedia presentation. This success criterion describes two approaches, either of which can be used.

One approach is to provide audio description of the video content. The audio description augments the audio portion of the presentation with the information needed when the video portion is not available. During existing pauses in dialogue, audio description provides information about actions, characters, scene changes, and on-screen text that are important and are not described or spoken in the main sound track.

The second approach involves providing all of the information in the multimedia (both visual and auditory) in text form. A full text alternative for multimedia including any interaction provides a running description of all that is going on in the multimedia content. The full text alternative for multimedia including any interaction reads something like a screenplay or book. Unlike audio description, the description of the video portion are not constrained to just the pauses in the existing dialogue. Full descriptions are provided of all visual information, including visual context, actions and expressions of actors, and any other visual material. In addition, non-speech sounds (laughter, off-screen voices, etc.) are described, and transcripts of all dialogue are included. The sequence of description and dialogue transcripts are the same as the sequence in the multimedia itself. As a result, the full text alternative for multimedia can provide a much more complete representation of the multimedia content than audio description alone.

If there is any interaction as part of the multimedia presentation (e.g. "press now to answer the question") then the full text alternative for multimedia would provide hyperlinks or whatever is needed to provide parallel functionality.

Techniques for Addressing Success Criterion 1.2.2

Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this criterion. The techniques listed only satisfy the success criterion if all of the WCAG 2.0 conformance requirements have been met.

Examples of Success Criterion 1.2.2

• A movie with audio description.

  Describer: A title, "Teaching Evolution Case Studies. Bonnie Chen." A teacher shows photographs of birds with long, thin beaks.

  Bonnie Chen: "These photos were all taken at the Everglades."

  Describer: The teacher hands each student two flat, thin wooden sticks.

  Bonnie Chen: "Today you will pretend to be a species of wading bird that has a beak like this."

  Describer: The teacher holds two of the sticks to her mouth making the shape of a beak.

  Transcript of audio based on the first few minutes of "Teaching Evolution Case Studies, Bonnie Chen" (copyright WGBH and Clear Blue Sky Productions, Inc.)

• A full text alternative for multimedia including any interaction for a training video

  A company purchases a Training video for use by its employees and puts it on the companies intranet. The video involves explaining use of a new technology and has a person talking and showing things at the same time. Since there is no place to insert audio description of the visual demonstrations during gaps in dialogue, the company provides a full text alternative for multimedia that all employees, including those who cannot see the demonstrations, can use to better understand what is being presented.

Related Resources

Resources are for information purposes only, no endorsement implied.

• NCAM Rich Media Accessibility, Accessible SMIL Templates

• Standard Techniques in Audio Description

• Provide audio description for video or animated content - general advice

• Synchronized Multimedia Integration Language (SMIL) 1.0

• Synchronized Multimedia Integration Language (SMIL 2.0)

• Accessibility Features of SMIL

Intent of this Success Criterion

The intent of this success criterion is to enable people who are deaf or hard of hearing to watch real-time presentations. Captions provide the part of the content available via the audio track. Captions not only include dialogue, but also identify who is speaking and notate sound effects and other significant audio.

Techniques for Addressing Success Criterion 1.2.3

Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this criterion. The techniques listed only satisfy the success criterion if all of the WCAG 2.0 conformance requirements have been met.

Examples of Success Criterion 1.2.3

• A Web cast

  A news organization provides a live, captioned Web cast.

Related Resources

Resources are for information purposes only, no endorsement implied.

(none currently documented)

See How to Meet Success Criterion 1.2.1 (Captions (Prerecorded)) .

Intent of this Success Criterion

The intent of this success criterion is to provide people who are blind or visually impaired access to the visual information in a multimedia presentation. The audio description augments the audio portion of the presentation with the information needed when the video portion is not available. During existing pauses in dialogue, audio description provides information about actions, characters, scene changes, and on-screen text that are important and are not described or spoken in the main sound track.

Techniques for Addressing Success Criterion 1.2.4

Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this criterion. The techniques listed only satisfy the success criterion if all of the WCAG 2.0 conformance requirements have been met.

Examples of Success Criterion 1.2.4

• A movie with audio description.

  Describer: A title, "Teaching Evolution Case Studies. Bonnie Chen." A teacher shows photographs of birds with long, thin beaks.

  Bonnie Chen: "These photos were all taken at the Everglades."

  Describer: The teacher hands each student two flat, thin wooden sticks.

  Bonnie Chen: "Today you will pretend to be a species of wading bird that has a beak like this."

  Describer: The teacher holds two of the sticks to her mouth making the shape of a beak.

  Transcript of audio based on the first few minutes of "Teaching Evolution Case Studies, Bonnie Chen" (copyright WGBH and Clear Blue Sky Productions, Inc.)

Related Resources

Resources are for information purposes only, no endorsement implied.

• NCAM Rich Media Accessibility, Accessible SMIL Templates

• Standard Techniques in Audio Description

• Provide audio description for video or animated content - general advice

• Synchronized Multimedia Integration Language (SMIL) 1.0

• Synchronized Multimedia Integration Language (SMIL 2.0)

• Accessibility Features of SMIL

Intent of this Success Criterion

The intent of this success criterion is to enable people who are deaf or hard of hearing and who are fluent in a sign language to understand the content of the audio track of multimedia presentations. Written text, such as that found in captions, is often a second language. Some individuals will require sign language interpretation to gain full access to the multimedia content. [LC-591]

Techniques for Addressing Success Criterion 1.2.5

Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this criterion. The techniques listed only satisfy the success criterion if all of the WCAG 2.0 conformance requirements have been met.

Examples of Success Criterion 1.2.5

• Example 1. A corporation is making an important announcement to all of its employees. The meeting will be held in the main headquarters and streamed to the Web. A sign language interpreter is provided at the meeting location. The live video includes a full view of the sign language interpreter as well as the person presenting.

• Example 2. The same announcement described in example 1 is also Webcast to remote employees. Since there is only one display available for this, the sign language interpreter is shown in the corner of the display.

• Example 3. A university is providing an on-line version of a particular lecture by creating a multimedia presentation of the professor delivering the lecture. The presentation includes video of the professor speaking and demonstrating a science experiment. A sign language interpretation of the lecture is created and presented on the Web with the multimedia version.

Related Resources

Resources are for information purposes only, no endorsement implied.

• Synchronized Multimedia Integration Language (SMIL) 1.0

• Synchronized Multimedia Integration Language (SMIL 2.0)

• Accessibility Features of SMIL

• NCAM Rich Media Accessibility, Accessible SMIL Templates

• National Center on Deafness list of interpreter links

• National Institute on Deafness and other Communication Disorders: Information on American Sign Language

• Techniques for filming sign language interpreters

• Royal National Institute for Deaf People (RNID)

Intent of this Success Criterion

The intent of this success criterion is to provide people who are blind or visually impaired access to a multimedia presentation beyond that which can be provided by standard audio description. This is done by periodically freezing the multimedia presentation and playing additional audio description. The multimedia presentation is then resumed.

Because it disrupts viewing for those who do not need the additional description, techniques that allow you to turn the feature on and off are often provided. Alternately, versions with and without the additional description can be provided.

Techniques for Addressing Success Criterion 1.2.6

Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this criterion. The techniques listed only satisfy the success criterion if all of the WCAG 2.0 conformance requirements have been met.

Examples of Success Criterion 1.2.6

• Example 1. Video of a lecture. A physics professor is giving a lecture. He makes freehand sketches on the whiteboard, speaking rapidly as he draws. As soon as he has finished discussing one problem, he erases the drawing and makes another sketch while continuing to speak and gesture with his other hand. The video is paused between problems, and extended audio description of the professor’s drawings and gestures is provided; the video is then resumed.

Related Resources

Resources are for information purposes only, no endorsement implied.

• Synchronized Multimedia Integration Language (SMIL) 1.0

• Synchronized Multimedia Integration Language (SMIL) 2.0

• Accessibility Features of SMIL

• NCAM Rich Media Accessibility, Accessible SMIL Templates

• Standard Techniques in Audio Description

Intent of this Success Criterion

The intent of this success criterion is to make audio visual material available to individuals whose vision is too poor to reliably read captions and whose hearing is too poor to reliably hear dialogue and audio description. This is done by providing a full text alternative for multimedia including any interaction.

This approach involves providing all of the information in the multimedia (both visual and auditory) in text form. A full text alternative for multimedia including any interaction provides a running description of all that is going on in the multimedia content. The full text alternative for multimedia reads something like a book. Unlike audio description, the description of the video portion is not constrained to just the pauses in the existing dialogue. Full descriptions are provided of all visual information, including visual context, actions and expressions of actors, and any other visual material. In addition, non-speech sounds (laughter, off-screen voices, etc.) are described, and transcripts of all dialogue are included. The sequence of descriptions and dialogue transcripts is the same as the sequence in the multimedia itself. As a result, the full text alternative for multimedia can provide a much more complete representation of the multimedia content than audio description alone.

If there is any interaction as part of the multimedia presentation (e.g. "press now to answer the question") then the full text alternative for multimedia would provide hyperlinks or whatever is needed to provide parallel functionality.

Individuals whose vision is too poor to reliably read captions and whose hearing is too poor to reliably hear dialogue can access the full text alternative for multimedia by using a refreshable braille display.

Techniques for Addressing Success Criterion 1.2.7

Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this criterion. The techniques listed only satisfy the success criterion if all of the WCAG 2.0 conformance requirements have been met.

Examples of Success Criterion 1.2.7

• Example 1. full text alternative for multimedia for a training video

  A community center purchases a Training video for use by its clients and puts it on the center’s intranet. The video involves explaining use of a new technology and has a person talking and showing things at the same time. The community center provides a full text alternative for multimedia that all clients, including those who can neither see the demonstrations nor hear the explanations in the multimedia, can use to better understand what is being presented.

Related Resources

Resources are for information purposes only, no endorsement implied.

(none currently documented)

Intent of Guideline 1.3

The purpose of this guideline is to ensure that all information is available in a form that can be perceived by all users. If all of the information is available in a form that can be determined by software, then it can be presented to users in different ways (visually, audibly, tactilely etc.). If information is embedded in a particular presentation in such a way that the structure and information cannot be programmatically determined by the assistive technology, then it cannot be rendered in other formats as needed by the user. [LC-1201]

The success criteria under this guideline all seek to ensure that different types of information that are often encoded in presentation are also available so that they can be presented in other modalities.

• structure: the way the parts of a Web page are organized in relation to each other; and the way a collection of Web pages is organized

• presentation: rendering of the content in a form that can be perceived by users

Intent of this Success Criterion

The intent of this success criterion is to ensure that information and relationships that are implied by visual or auditory formatting are preserved when the presentation format changes. For example, the presentation format changes when the content is read by a screen reader or when a user style sheet is substituted for the style sheet provided by the author.

Sighted users perceive structure through various visual cues — headings are often in a larger, bold font separated from paragraphs by blank lines; list items are preceded by a bullet and perhaps indented; paragraphs are separated by a blank line; items that share a common characteristic are organized into tabular rows and columns; form fields may be positioned as groups that share text labels; a different background color may be used to indicate that several items are related to each other; words that have special status are indicated by changing the font family and /or bolding, italicizing, or underlining them and so on [LC-588] .

Auditory cues may be used as well. For example, a chime might indicate the beginning of a new section; a change in voice pitch or speech rate may be used to emphasize important information or to indicate quoted text; etc.

When such relationships are perceivable to one set of users, those relationships can be made to be perceivable to all. One method of determining whether or not information has been properly provided to all users is to access the information serially in different modalities.

If links to glossary items are implemented using anchor elements (or the proper link element for the technology in use) and identified using a different font face, a screen reader user will hear that the item is a link when the glossary term is encountered even though they may not receive information about the change in font face. An on-line catalog may indicate prices using a larger font colored red. A screen reader or person who can not perceive red, still has the information about the price as long as it is preceded by the currency symbol.

Some technologies do not provide a means to programmatically determine some types of information and relationships. In that case then there should be a text description of the information and relationships. For instance, "all required fields are marked with an asterisk (*)". The text description should be near the information it is describing (when the page is linearized), such as in the parent element or in the adjacent element.

Techniques for Addressing Success Criterion 1.3.1

Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this criterion. The techniques listed only satisfy the success criterion if all of the WCAG 2.0 conformance requirements have been met.

Examples of Success Criterion 1.3.1

• A form with required fields

  A form contains several required fields. The labels for the required fields are displayed in red. In addition, at the end of each label is an asterisk character, *. The instructions for completing the form indicate that "all required fields are displayed in red and marked with an asterisk *", followed by an example. [LC-1079]

• A form that uses color and text to indicate required fields

  A form contains both required and optional fields. Instructions at the top of the form explain that required fields are labeled with red text and also with an icon whose text alternative says, “Required.” . Both the red text and the icon are programmatically associated with the appropriate form fields so that assistive technology users can determine the required fields. [LC-1079]

• A bus schedule table where the headers for each cell can be programmatically determined

  A bus schedule consists of a table with the bus stops listed vertically in the first column and the different buses listed horizontally across the first row. Each cell contains the time when the bus will be at that bus stop. The bus stop and bus cells are identified as headers for their corresponding row or column so that assistive technology can programmatically determine which bus and which bus stop are associated with the time in each cell.

• A form where the labels for the checkboxes can be programmatically determined

  In a form, the labels for each checkbox can be programmatically determined by assistive technology.

• A text document

  A simple text document is formatted with double blank lines before titles, asterisks to indicate list items and other standard formatting conventions so that its structure can be programmatically determined.

Intent of this Success Criterion

The intent of this success criterion is to ensure that all users can access information that is conveyed by color. If the information is conveyed through color in an image (or other non-text format), the color cannot be programmatically determined by assistive technology. In this case, providing the information conveyed with color through another means ensures that assistive technology users who cannot see the color can still perceive the information.

Color is an important asset in design of Web content, enhancing its aesthetic appeal, its usability, and its accessibility. However, some users have difficulty perceiving color. People with partial sight often experience limited color vision, and many older users do not see color well. In addition, people using text-only, limited-color or monochrome displays and browsers will be unable to access information that is presented only in color.

Techniques for Addressing Success Criterion 1.3.2

Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this criterion. The techniques listed only satisfy the success criterion if all of the WCAG 2.0 conformance requirements have been met.

Examples of Success Criterion 1.3.2

• A form that uses color and text to indicate required fields

  A form contains both required and optional fields. Instructions at the top of the form explain that required fields are labeled with red text and also with an icon whose text alternative says, “Required.” . Both the red text and the icon are programmatically associated with the appropriate form fields so that assistive technology users can determine the required fields.

• An examination.

  Students view an SVG image of a chemical compound and identify the chemical elements present based on the colors used in the diagram. The text alternatives associated with each element name the color of the element and indicate the element's position in the diagram. Students who cannot perceive color have the same information about the compound as their classmates. (This technique also satisfies Guideline 1.1 Level 1.)

• Disabled Form elements.

  Form elements which are disabled via markup or scripting, are greyed out and made inactive by the user agent. When in the disabled state these elements do not receive focus. Assistive technologies can programmatically determine the state of disabled elements and will provide this information to the user as the elements are encountered on the page. The change in color and loss of focus provides redundant, visual information about the state of the control. [LC-717]

Related Resources

Resources are for information purposes only, no endorsement implied.

(none currently documented)

Intent of this Success Criterion

The intent of this success criterion is to enable a user agent to provide an alternative presentation of content while preserving the reading order needed to perceive meaning. It is important that it be possible to programmatically determine at least one sequence of the content that makes sense. Content that does not meet this success criterion may confuse or disorient users when assistive technology reads the content in the wrong order, or when alternate style sheets or other formatting changes are applied.

A sequence is meaningful if the order of content in the sequence cannot be changed without affecting its meaning. For example, if a page contains two independent articles, the relative order of the articles may not affect their meaning, as long as they are not interleaved. In such a situation, the articles themselves may have meaningful sequence, but the container that contains the articles may not have a meaningful sequence.

The semantics of some elements define whether or not their content is a meaningful sequence. For instance, in HTML, text is always a meaningful sequence. Tables and ordered lists are meaningful sequences, but unordered lists are not.

Techniques for Addressing Success Criterion 1.3.3

Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this criterion. The techniques listed only satisfy the success criterion if all of the WCAG 2.0 conformance requirements have been met.

Examples of Success Criterion 1.3.3

• Example 1: In a multi-column document, the linear presentation of the content flows from the top of a column to the bottom of the column, then to the top of the next column.

• Example 2: CSS is used to position a navigation bar, the main story on a page, and a side story. The visual presentation of the sections does not match the programmatically determined order, but the meaning of the page does not depend on the order of the sections.

Intent of this Success Criterion

The intent of this success criterion is to ensure that all users can access instructions for using the content, even when they cannot perceive shape or size or use information about spatial location or orientation. Some content relies on knowledge of the shape or position of objects that are not available from the structure of the content (for example, "round button" or "button to the right"). Some users with disabilities are not able to perceive shape or position due to the nature of the assistive technologies they use. This success criterion requires that additional information be provided to clarify anything that is dependent on this kind of information.

Providing information using shape and/or location, however, is an effective method for many users including those with cognitive limitations. This provision should not discourage those types of cues as long as the information is also provided in other ways.

Techniques for Addressing Success Criterion 1.3.4

Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this criterion. The techniques listed only satisfy the success criterion if all of the WCAG 2.0 conformance requirements have been met.

Examples of Success Criterion 1.3.4

• Example 1: A schedule of competitive events uses color and shape to distinguish the time of each event

  A table presents a list of times across the top row and a list of events in the first vertical column. The cell corresponding to the time of a particular event has a specific background color and diamond shaped glyph so it can be identified by color and shape. [LC-1082]

• Example 2: An online multi-page survey

  An online multi-page survey uses a link implemented as a green arrow icon placed in the lower right hand corner of the content to move from one survey page to the next. The arrow is clearly labeled with "Next" and the instructions state, "To move to the next section of the survey, select the green arrow icon labeled 'Next' in the lower right below the last survey question." This example uses both positioning, color and labeling to help identify the icon. [LC-1082]

Intent of Guideline 1.4

While some guidelines are focused on making information available in a form that can be presented in alternate formats, this guideline is concerned with making the default presentation as usable as possible to people with disabilities. The primary focus is on making it easier for users to separate foreground information from the background. For visual presentations this involves making sure that information presented on top of a background contrasts sufficiently with the background. For audio presentations this involves making sure that foreground sounds are sufficiently louder than the background sounds. Individuals with visual and hearing disabilities have much greater difficulty separating foreground and background information.

Intent of this Success Criterion

Individuals who use screen reading software can find it hard to understand the speech output if there is other audio playing at the same time. This difficulty is exacerbated when the screen reader's speech output is software based (as most are today) and is controlled via the same volume control as the sound.

Techniques for Addressing Success Criterion 1.4.1

Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this criterion. The techniques listed only satisfy the success criterion if all of the WCAG 2.0 conformance requirements have been met.

Examples of Success Criterion 1.4.1

• An audio file begins playing automatically when a page is opened. However, the audio can be stopped by the user by selecting a "silent" link at the top of the page.

  An audio file begins playing automatically when a page is opened. However, the audio can be stopped by the user by selecting a "silent" link at the top of the page.

• A Flash splash page with sound that plays and then stops in less than 3 seconds. [LC-794]

• A Flash splash page with sound that plays that can be turned off. [LC-794]

Intent of this Success Criterion

The intent of this success criterion is to provide enough contrast between text and its background so that it can be easily read by people with low vision. The contrast is calculated in such a way that color is not a key factor so that people who also have a color vision deficit will also see a contrast between the text and the background. Decorations that are included in an image along with a diagram but that convey no information are not part of the diagram. [LC-1161]

The 5:1 contrast ratio provides a minimum contrast of around 3:1 for the major types of color blindness. A contrast ratio of 3:1 is the minimum level recommended by [ISO-9241-3] and [ANSI-HFES-100-1988].

Calculations in ISO 9241-3 and ANSI/HFS 100-1988 are for body text. A relaxed contrast ratio is provided for text that is much larger (twice as tall and with three time the thickness of lines in the character).

Techniques for Addressing Success Criterion 1.4.2

Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this criterion. The techniques listed only satisfy the success criterion if all of the WCAG 2.0 conformance requirements have been met.

Examples of Success Criterion 1.4.2

Related Resources

Resources are for information purposes only, no endorsement implied.

• Luminosity Contrast Analyser – Application

• Luminosity Contrast Ratio Analyser - online service

• Colour Contrast Analyser - Firefox Extension

• Color Contrast Samples

Intent of this Success Criterion

The intent of this success criterion is to provide enough contrast between text and its background so that it can be easily read by people with low vision. The contrast is calculated in such a way that color is not a key factor so that people who also have a color vision deficit will also see a contrast between the text and the background. Decorations that are included in an image along with a diagram but that convey no information are not part of the diagram. [LC-1161]

The 10:1 contrast ratio provides a minimum contrast of around 7:1 for the major types of color blindness. A contrast ratio of 7:1 is recommended by [ANSI-HFES-100-1988].

Calculations in ISO 9241-3 and ANSI/HFS 100-1988 are for body text. A relaxed contrast ratio is provided for text that is much larger (twice as tall and with three time the thickness of lines in the character).

Techniques for Addressing Success Criterion 1.4.4

Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this criterion. The techniques listed only satisfy the success criterion if all of the WCAG 2.0 conformance requirements have been met.

Examples of Success Criterion 1.4.4

Related Resources

Resources are for information purposes only, no endorsement implied.

• Luminosity Contrast Analyser – Application

• Luminosity Contrast Ratio Analyser - online service

• Colour Contrast Analyser - Firefox Extension

• Color Contrast Samples

Intent of this Success Criterion

The intent of this success criterion is to ensure that any non-speech sounds are low enough that a user who is hard of hearing can understand the speech. Individuals who are hard of hearing have difficulty separating speech from background sounds or other noise. Background sound that meets this requirement will be approximately one quarter as loud as the foreground speech content. [LC-743]

The value of 20 dB was chosen based on Large area assistive listening systems (ALS): Review and recommendations [LAALS] and In-the-ear measurements of interference in hearing aids from digital wireless telephones [HEARING-AID-INT] [LC-1228]

Techniques for Addressing Success Criterion 1.4.5

Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this criterion. The techniques listed only satisfy the success criterion if all of the WCAG 2.0 conformance requirements have been met.

Examples of Success Criterion 1.4.5

Related Resources

Resources are for information purposes only, no endorsement implied.

• About Decibels

Intent of Guideline 2.1

If all functionality can be achieved using the keyboard, it can be accomplished by keyboard users, by speech input (which creates keyboard input), by mouse (using on-screen keyboards), and by a wide variety of assistive technologies that create simulated keystrokes as their output. No other input form has this flexibility or is universally supported and operable by people with different disabilities, as long as the keyboard input is not time-dependent.

Note that providing universal keyboard input does not mean that other types of input should not be supported. Optimized speech input, optimized mouse/pointer input, etc., are also good. The key is to provide keyboard input and control as well.

Some devices do not have native keyboards—for example, a PDA or cell phone. If these devices have a Web browsing capability, however, they will have some means of generating text or "keystrokes." This guideline uses the term "keyboard interface" to acknowledge that Web content should be controlled from keystrokes that may come from a keyboard, keyboard emulator, or other hardware or software that generates keyboard or text input.

Intent of this Success Criterion

The intent of this success criterion is to ensure that, wherever possible, content can be operated through a keyboard or keyboard interface. When content can be operated through a keyboard or alternate keyboard, it is operable by people with no vision (who cannot use devices such as mice that require eye-hand coordination) as well as by people who must use alternate keyboards or input devices that act as keyboard emulators. Keyboard emulators include speech input software, sip-and-puff software, on-screen keyboards, scanning software and a variety of assistive technologies and alternate keyboards. Individuals with low vision also may have trouble tracking a pointer and find the use of software much easier (or only possible) if they can control it from the keyboard.

Examples of "specific timings for individual keystrokes" include situations where a user would be required to repeat or execute multiple keystrokes within a short period of time or where a key must be held down for an extended period before the keystroke is registered. [LC-1164]

The phrase "except where the task requires analog, time-dependent input" is included to separate those things that cannot reasonably be controlled from a keyboard. For example, a watercolor application where the stroke is defined by the movement and speed of movement and/or pressure is not something that can be controlled from a keyboard. Also, the use of MouseKeys would not satisfy this success criterion because it is not a keyboard equivalent to the application; it is a mouse equivalent (i.e. it looks like a mouse to the application).

When considering whether analog, time-dependent input is required for the underlying task (what you are trying to do) a key question is, could you achieve the same functionality in a different way using an input device that was not analog, time-dependent (e.g. using a keyboard). [LC-922]

Techniques for Addressing Success Criterion 2.1.1

Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this criterion. The techniques listed only satisfy the success criterion if all of the WCAG 2.0 conformance requirements have been met.

Examples of Success Criterion 2.1.1

• Example 1: A drawing Program.

  A drawing program allows users to create, size, position and rotate objects from the keyboard.

• Example 2: A drag and Drop Feature.

  An application that uses drag and drop also supports "cut" and "paste" or form controls to move objects.

• Example 3: Moving between and connecting discrete points.

  A connect-the-dots program allows the user to move between dots on a screen and use the spacebar to connect the current dot to the previous one.

• Example 4: Exception - Painting Program.

  A watercolor painting program passes as an exception because the brush strokes vary depending on the speed and duration of the movements.

• Example 5: Exception - Model helicopter flight training simulator.

  A model helicopter flight training simulator passes as an exception because the nature of the simulator is to teach real-time behavior of a model helicopter.

• Example 6: A PDA with an optional keyboard

  A PDA device that is usually operated via a stylus has an optional keyboard that can be attached. The keyboard allows full Web browsing in standard fashion. The Web content is operable because it was designed to work with keyboard-only access.

Intent of this Success Criterion

The intent of this success criterion is to ensure that all content is operable from the keyboard.This is the same as success criterion 2.1.1, except that no exceptions are allowed. This does not mean that analog, time-dependent input (excluded from the requirements of 2.1.1) must be made keyboard accessible. Rather, it means that content that uses analog, time-dependent input cannot conform to this success criterion and therefore cannot meet Guideline 2.1 at Level 3.

Techniques for Addressing Success Criterion 2.1.2

Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this criterion. The techniques listed only satisfy the success criterion if all of the WCAG 2.0 conformance requirements have been met.

Intent of Guideline 2.2

Many users who have disabilities need more time to complete tasks than the majority of users: they may take longer to physically respond, they may take longer to read things, they may have low vision and take longer to find things or to read them, or they may be accessing content through an assistive technology that requires more time. This guideline focuses on ensuring that users are able to complete the tasks required by the content with their own individual response times. The primary approaches deal with eliminating time constraints or providing users enough additional time to allow them to complete their tasks. Exceptions are provided for those cases where this is not possible.

Intent of this Success Criterion

The intent of this success criterion is to ensure that users with disabilities are given adequate time to interact with Web content whenever possible. People with disabilities such as blindness, dexterity impairments, and cognitive limitations may require more time to perform functions such as filling out on-line forms. If Web functions are time-dependent, it will be difficult for some users to perform the required action before a time limit occurs. This may render the service inaccessible to them. Designing functions that are not time-dependent will help people with disabilities succeed at completing these functions. Providing options to disable time limits, customize the length of time limits, or request more time before a time limit occurs helps those users who require more time than expected to successfully complete tasks. Any process that happens without user initiation after a set time or on a periodic basis is a time limit. This includes partial or full updates of content, changes to content, or the expiration of a window of opportunity for a user to react to a request for input. [LC-1089]

In some cases, however, it is not possible to change the time limit (for example, for an auction or other real-time event) and exceptions are therefore provided for those cases.

Notes regarding server time limits

• Timed server redirects can be found below under Common Failures.

• Server time limits like login expiration are dealt with in success criterion 2.2.6.

• Non-timed server redirects (e.g. 3xx response codes) are not applicable because there is no time limit: they work instantly.

• This Success Criterion applies only to time limits that are set by the content itself. Time limits set externally to content, such as by the user agent or by factors intrinsic to the Internet, are not under the author's control and not subject to WCAG conformance requirements. Time limits set by Web servers should be under the author's control and are addressed by other SC. [LC-1166]

• 10 times the default was chosen based on clinical experience and other guidelines. For example, if 15 seconds is allowed for a user to respond and hit a switch, 150 seconds would be sufficient to allow almost all users to hit a switch even if they had trouble. [LC-1230]

• 20 seconds was also based on clinical experience and other guidelines. 20 seconds to hit 'any switch' is sufficient for almost all users including those with spasticity. Some would fail, but some would fail all lengths of time. A reasonable period for requesting more time is required since an arbitrarily long time can provide security risks to all users, including those with disabilities, for some applications. For example, with kiosks or terminals that are used for financial transactions, it is quite common for people to walk away without signing off. This leaves them vulnerable to those walking up behind them. Providing a long period of inactivity before asking, and then providing a long period for the person to indicate that they are present can leave terminals open for abuse. If there is no activity the system should ask if the user is there. It should then ask for an indication that a person is there ('hit any key') and then wait long enough for almost anyone to respond. For "hit any key," 20 seconds would meet this. If the person indicates that they are still present, the device should return the user to the exact condition that existed before it asked the question. [LC-1230]

Techniques for Addressing Success Criterion 2.2.1

Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this criterion. The techniques listed only satisfy the success criterion if all of the WCAG 2.0 conformance requirements have been met.

Examples of Success Criterion 2.2.1

• A Web site uses a client side time limit to help protect consumers who may step away from their computer. After a period of inactivity the Web page asks if the user needs more time. If it doesn’t get a response – it times out.

• A Web page has a field that automatically updates with the latest headlines in a rotating fashion. There is an interactive control that allows the user to extend the length of time between each update to as much as 10 times the default. The control can be operated with either a mouse or a keyboard. [LC-783]

• In an auction, there is a time limit on the amount of time a user has to submit a bid. Since the time limit applies to all users who want to bid on a particular item, it would be unfair to extend the time limit for any one particular user. Therefore, a time limit is required for this type of activity and no extension, adjustment, or deactivation of the time limit is required by this success criteria. [LC-1046]

• An online ticket-purchasing site gives the user two minutes to confirm a purchase before the seats are returned to the general pool. Because tickets on such sites can sell out quickly, holding a ticket longer than that may invalidate the nature of the site, so this is a case in which the timing is essential and cannot be extended without invalidating the activity. However, the site does move as much of the process out of the time-critical period as possible, for instance allowing users to provide necessary information like name, payment method, etc., before entering the time-critical stage. [LC-1167]

• A ticket-purchasing site allows the user two minutes to confirm purchase of selected seats, but warns the user when their time is almost out and allows the user to extend this time limit some number of times with a simple action such as clicking a "Extend time limit" button. [LC-1167]

Related Resources

Resources are for information purposes only, no endorsement implied.

(none currently documented)

Intent of this Success Criterion

The intent of this success criterion is to avoid distracting users during their interaction with a Web page. Certain groups, particularly those with attention deficit disorders, find blinking content distracting, making it difficult for them to concentrate on other parts of the Web page. Three seconds was chosen because it is long enough to get a user's attention, but not so long that a user can not wait it out if necessary in order to use the page and the blinking blocks their ability to focus on the page.

Techniques for Addressing Success Criterion 2.2.2

Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this criterion. The techniques listed only satisfy the success criterion if all of the WCAG 2.0 conformance requirements have been met.

Examples of Success Criterion 2.2.2

• Example 1: A Web advertisement blinks to get viewers attention but stops after 3 seconds

• Example 2: A form blinks an arrow near the submit button if a user finishes filling out the form but does not activate the submit button. The blinking stops after 3 seconds.

• Example 3: An animation runs in the upper portion of the page but has a "freeze animation" button near the bottom of the animation.

Related Resources

Resources are for information purposes only, no endorsement implied.

(none currently documented)

Intent of this Success Criterion

The intent of this success criterion is to provide an option to temporarily stop content from advancing or updating at a rate beyond the user's ability to read and/or understand the content as it changes.

"Moving" refers to content in which the visible content conveys a sense of motion. Common examples include motion pictures, multimedia presentations, animations, real-time games, and scrolling stock tickers.

"Time-based" refers to content that updates or disappears based on a preset time interval. Common time-based content includes audio, automatically updated weather information, news, stock price updates, and auto-advancing presentations and messages.

Techniques for Addressing Success Criterion 2.2.3

Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this criterion. The techniques listed only satisfy the success criterion if all of the WCAG 2.0 conformance requirements have been met.

Examples of Success Criterion 2.2.3

• An essential animation can be paused without effecting the activity

  A Web site helps users understand 'how things work' through animations that demonstrate processes. Animations have "pause" and "restart" buttons.

• A stock ticker.

  A stock ticker has "pause" and "restart" buttons. Pausing the ticker causes it to pause on the currently displayed stock. Restarting causes the ticker to resume from the stopped point but with a notice that the display is delayed. Since the intent of the stock ticker is usually to provide realtime information, there might also be a button that would advance the ticker to the most recently traded stock. [LC-772]

• A game is designed so that users take turns rather than competing in real-time

  One party can pause the game without invalidating the competitive aspect of it.

Related Resources

Resources are for information purposes only, no endorsement implied.

(none currently documented)

Intent of this Success Criterion

The intent of this success criterion is to minimize the occurrence of content that requires timed interaction. This enables people with blindness, low vision, cognitive limitations, or motor impairments to interact with content. This differs from the Level 1 success criterion in that the only exception is for real-time events.

Techniques for Addressing Success Criterion 2.2.4

Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this criterion. The techniques listed only satisfy the success criterion if all of the WCAG 2.0 conformance requirements have been met.

Examples of Success Criterion 2.2.4

• A test is designed so that time to complete the test does not effect the scoring

  Rather than calibrating an on-line test using a time limit, the test is calibrated based on scores when users have no time limits.

• A game is designed so that users take turns rather than competing in real-time

  One party can pause the game without invalidating the competitive aspect of it.

Related Resources

Resources are for information purposes only, no endorsement implied.

(none currently documented)

Intent of this Success Criterion

The intent of this success criterion is to allow users to turn off updates from the author/server except in emergencies. Emergencies would include civil emergency alert messages or any other messages that warn of danger to health, safety, or property, including data loss, loss of connection, etcetera.

This allows access by people with cognitive limitations or attention disorders to be able to focus on the content. It also allows users who are blind or have low vision to keep their "viewing" focus on the content they are currently reading.

Techniques for Addressing Success Criterion 2.2.5

Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this criterion. The techniques listed only satisfy the success criterion if all of the WCAG 2.0 conformance requirements have been met.

Examples of Success Criterion 2.2.5

• Example 1. Setting user preferences

  The preferences page of a Web portal includes an option to postpone all updates and alerts until the end of the current session, except for alerts concerning emergencies.

Related Resources

Resources are for information purposes only, no endorsement implied.

(none currently documented)

Intent of this Success Criterion

The intent of this success criterion is to allow all users to complete authenticated transactions that have inactivity time limits. For security reasons, many sites implement an authentication time limit after a certain period of inactivity. These time limits may cause problems for persons with disabilities because it may take longer for them to complete the activity. These users must be given the ability to re-authenticate and continue with the transaction without the loss of any data already entered.

Techniques for Addressing Success Criterion 2.2.6

Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this criterion. The techniques listed only satisfy the success criterion if all of the WCAG 2.0 conformance requirements have been met.

Examples of Success Criterion 2.2.6

• A shopping site checkout

  A user with extremely limited use of the hands is logged into a shopping site. It takes so long to enter credit card information into the application that a time limit occurs wile the user is performing the checkout process. When the user returns to the checkout process and submits the form, the site returns a login screen to re-authenticate. After the user logs in, the check out process is restored with the same information and at the same stage. The user did not lose any data because the server had temporarily accepted and stored the submission even though the session had timed out and restored the user to the same state after re-authentication was completed.

• Authentication in an email program

  An email program has an authentication time-out after 30 minutes. The program prompts the user several minutes before the time-out occurs and provides a link to open a new window in order to re-authenticate. The original window with the in-progress email remains intact and, after re-authentication, the user may send that data.

• A questionnaire with a time limit

  A long questionnaire provided within a single Web page has information at the beginning that indicates that the session will time out after 15 minutes. The user is also informed that the questionnaire can be saved at any point and completed at a later time. Within the Web page there are several buttons provided to save the partially completed form. In addition, with JavaScript in the list of accessibility-supported content technologies that are relied on, the user can elect to be alerted via a pop-up if the session is close to timing out.

Related Resources

Resources are for information purposes only, no endorsement implied.

(none currently documented)

Intent of Guideline 2.3

Some people with seizure disorders can have a seizure triggered by flashing visual content. Most people are unaware that they have this disorder until it strikes. In 1997, a cartoon on television in Japan sent over 700 children to the hospital, including about 500 who had seizures [EPFND]. Warnings do not work well because they are often missed, especially by children who may in fact not be able to read them.

The objective of this guideline is to ensure that content that is marked as conformant to WCAG 2.0 avoids the types of flash that are most likely to cause seizure when viewed even for a second or two.

Intent of this Success Criterion

The intent of this success criterion is to allow users to access the full content of a site without inducing seizures due to photosensitivity.

Individuals who have photosensitive seizure disorders can have a seizure triggered by content that flashes at certain frequencies for more than a few flashes. People are even more sensitive to red flashing than to other colors, so a special test is provided for saturated red flashing. These guidelines are based on guidelines for the broadcasting industry as adapted for computer screens, where content is viewed from a closer distance (using a larger angle of vision).

Flashing can be caused by the display, the computer rendering the image or by the content being rendered. The author has no control of the first two. They can be addressed by the design and speed of the display and computer. The intent of this criterion is to ensure that flicker that violates the flash thresholds is not caused by the content itself. For example, the content could contain a video clip or animated image of a series of strobe flashes, or close-ups of rapid-fire explosions. [LC-1414]

This success criterion replaces a much more restrictive criterion in WCAG 1.0 that did not allow any flashing (even of a single pixel) within a broad frequency range (3 to 50 Hz). This success criterion is based on existing specifications in use in England and by others for television broadcast and has been adapted for computer display viewing. The 1024 x 768 screen is used as the reference screen resolution for the evaluation. The 341 x 256 pixel block represents a 10 degree viewport at a typical viewing distance. (The 10 degree field is taken from the original specifications and represents the central vision portion of the eye, where people are most susceptible to photo stimuli.)

The combined area of flashes occurring concurrently (but not necessarily contiguously) means the total area that is actually flashing at the same time. It is calculated by adding up all of the areas of the individual flashes within any 341 x 256 pixel viewport that are occurring at the same time.

Techniques for Addressing Success Criterion 2.3.1

Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this criterion. The techniques listed only satisfy the success criterion if all of the WCAG 2.0 conformance requirements have been met.

Examples of Success Criterion 2.3.1

• A Web site has video of muzzle flash of machine gun fire, but limits the size of the flashing image to a small portion of the screen below the flash threshold size. [LC-1101]

• A movie with a scene involving very bright lightning flashes is edited so that the lightning only flashes three times in any one second period. [LC-785] [LC-1101]

Related Resources

Resources are for information purposes only, no endorsement implied.

• Harding FPA Web Site

• Trace Center Photosensitive Epilepsy Analysis Tool (PEAT)

• Information about Photosensitive Seizure Disorders

• Epilepsy Action

• Epilepsy Foundation

• Ofcom Guidance Note on Flashing Images and Regular Patterns in Television (PDF)

Intent of this Success Criterion

The intent of this success criterion is to allow users to access the full content of a site without inducing seizures due to photosensitivity.

Success criterion 2.3.1 requires that flashing content be less than three flashes in any 1-second period unless it is smaller than 40% of a 341 x 256 pixel area (on a 1024 x 768 screen). This would keep the stimuli to less than 40% of a person's central vision for a typical screen. However, some users access Web content through screen enlargers. For these people, the area described in section 2.3.1 would (when magnified) be more than 40% of a persons central vision.

This success criterion eliminates all flashing components that flash more than three times in any 1-second period. In this fashion, magnification at any level would not yield content that would fail the general flash or red flash thresholds.

Techniques for Addressing Success Criterion 2.3.2

Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this criterion. The techniques listed only satisfy the success criterion if all of the WCAG 2.0 conformance requirements have been met.

Examples of Success Criterion 2.3.2

• A movie with a scene involving very bright lightning flashes is edited so that the lightning only flashes three times in any one second period. [LC-785]

Related Resources

Resources are for information purposes only, no endorsement implied.

• Harding FPA Web Site

• Trace Center Photosensitive Epilepsy Analysis Tool (PEAT)

• Information about Photosensitive Seizure Disorders

• Epilepsy Action

• Epilepsy Foundation

• Ofcom Guidance Note on Flashing Images and Regular Patterns in Television (PDF)

Intent of Guideline 2.4

The intent of this guideline is to help users find the content they need and allow them to keep track of their location. These tasks are often more difficult for people with disabilities. For finding, navigation, and orientation, it is important that the user can find out what the current location is. For navigation, information about the possible destinations needs to be available. Screen readers convert content to synthetic speech which, because it is audio, must be presented in linear order. Some success criteria in this guideline explain what provisions need to be taken to ensure that screen reader users can successfully navigate the content. Others allow users to more easily recognize navigation bars and page headers and to bypass this repeated content. Unusual user interface features or behaviors may confuse people with cognitive disabilities. [LC-946]

This guideline works closely with Guideline 1.3, which ensures that any structure in the content can be perceived, a key to navigation as well. Headings are particularly important mechanisms for helping users orient themselves within content and navigate through it. Many users of assistive technologies rely on appropriate headings to skim through information and easily locate the different sections of content. Satisfying Success Criterion 1.3.1 for headings also addresses some aspects of Guideline 2.4. [LC-562]

Intent of this Success Criterion

The intent of this success criterion is to allow people who navigate sequentially through content more direct access to the primary content of the Web page. Web pages and applications often have content that appears on other pages or screens. Examples of repeated blocks of content include but are not limited to navigation links, heading graphics, and advertising frames.

This is in contrast to a sighted user's ability to ignore the repeated material either by focusing on the center of the screen (where main content usually appears) or a mouse user's ability to select a link with a single mouse click rather than encountering every link or form control that comes before the item they want.

Techniques for Addressing Success Criterion 2.4.1

Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this criterion. The techniques listed only satisfy the success criterion if all of the WCAG 2.0 conformance requirements have been met.

Examples of Success Criterion 2.4.1

• A news organization's home page contains a main story in the middle of the page, surrounded by many blocks and sidebars for advertising, searching, and other services. There is a link at the top of the page that jumps to the main story. Without using this link, a keyboard user needs to tab through approximately 40 links to reach the main story; the screen reader user has to listen to 200 words; and the screen magnifier user must search around for the location of the main body.

Related Resources

Resources are for information purposes only, no endorsement implied.

(none currently documented)

Intent of this Success Criterion

The intent of this success criterion is to help users find content and orient themselves within it by ensuring that each Web page has a descriptive title. Titles identify the current location without requiring users to read or interpret page content. When titles appear in site maps or lists of search results, users can more quickly identify the content they need. [LC-625]

Techniques for Addressing Success Criterion 2.4.2

Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this criterion. The techniques listed only satisfy the success criterion if all of the WCAG 2.0 conformance requirements have been met.

Examples of Success Criterion 2.4.2

• A document.

  The title of Web Content Accessibility Guidelines 2.0 is "Web Content Accessibility Guidelines 2.0."

  • The introduction has the title "Introduction to Web Content Accessibility Guidelines 2.0."

  • The main body has the title "WCAG 2.0 Guidelines."

  • Appendix A has the title "Glossary to Web Content Accessibility Guidelines 2.0."

  • Appendix B has the title "Checklist for Web Content Accessibility Guidelines 2.0."

  • Appendix C has the title "Acknowledgements for Web Content Accessibility Guidelines 2.0."

  • Appendix D has the title "References for Web Content Accessibility Guidelines 2.0."

• [LC-625]

• A Web application.

  A banking application lets a user inspect his bank accounts, view past statements, and perform transactions. The Web application dynamically generates titles for each Web page, e.g., "Bank XYZ, accounts for John Smith" "Bank XYZ, December 2005 statement for Account 1234-5678". [LC-625]

Related Resources

Resources are for information purposes only, no endorsement implied.

• Writing Better Web Page Titles How to write titles for Web pages that will enhance search engine effectiveness.

• Guidelines for Accessible and Usable Web Sites: Observing Users Who Work With Screen Readers. Theofanos, M.F., and Redish, J. (2003). Interactions, Volume X, Issue 6, November-December 2003, pages 38-51, http://portal.acm.org/citation.cfm?doid=947226.947227

Intent of this Success Criterion

The intent of this success criterion is to ensure that when users navigate sequentially through content, they encounter information in an order that reflects the logical relationships in the content. This reduces confusion by letting users form a consistent mental model of the content. There may be different orders that reflect logical relationships in the content. For example, move through components in a table one row at a time or one column at a time both reflect the logical relationships in the content. Either order would satisfy this success criterion. [LC-930]

An additional example of navigation is using arrow key navigation to traverse a tree component. The user can use the up and down arrow keys to move from tree node to tree node. Pressing the left arrow key may expand a node, then using the down arrow key, will move into the newly expanded nodes. This navigation sequence follows the expected sequence for a tree control - as additional items get expanded or collapsed, they are added or removed from the navigation sequence. [LC-930]

The way that sequential navigation order is determined in Web content is defined by the technology of the content. For example, simple HTML defines sequential navigation via the notion of tabbing order. Dynamic HTML may modify the navigation sequence using scripting along with the addition of a tabindex attribute to allow focus to additional elements. In this case, the navigation should follow relationships and sequences in the content. If no scripting or tabindex attributes are used, the navigation order is the order that components appear in the content stream. (See HTML 4.01 Specification, section 17.11, "Giving focus to an element"). [LC-974]

Techniques for Addressing Success Criterion 2.4.3

Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this criterion. The techniques listed only satisfy the success criterion if all of the WCAG 2.0 conformance requirements have been met.

Examples of Success Criterion 2.4.3

• Example that fails to meet the success criterion: : An on-line subscription form.

  A company's Web site includes a form that collects marketing data and allows users to subscribe to several newsletters published by the company. The section of the form for collecting marketing data includes fields such as name, street address, city, state or province, and postal code. Another section of the form includes several checkboxes so that users can indicate newsletters they want to receive. However, the tab order for the form skips between fields in different sections of the form.

  An individual using a screen magnifier fills in the form. Because of the level of magnification, only a small portion of the page is visible. She tabs through the fields, entering her name, then her street address. However, the next field in tab order is not the field for the city, but the checkbox beside the name of a newsletter. The user assumes that she has provided all of the necessary address information and presses Enter to submit the form. She is surprised when she receives an error message telling her that one or more required fields is incomplete. [LC-1111]

Related Resources

Resources are for information purposes only, no endorsement implied.

(none currently documented)

Intent of this Success Criterion

The intent of this success criterion is to help users understand the purpose of each link so they can decide whether they want to follow the link. This is generally achieved by reading the link itself. Assistive technology has the ability to provide users with a list of links that are on the Web page. Link text that is as meaningful as possible will aid users who want to choose from this list of links. Meaningful link text also helps those who wish to tab from link to link. Meaningful links help users choose which links to follow without requiring complicated strategies to understand the page.

In some situations, authors may want to provide part of the description of the link in the nearby text. In this case the user should be able to identify the purpose of the link without moving focus from the link. In other words, they can arrive on a link and find out more about it without losing their place. This can be achieved by putting the description of the link in the same sentence, paragraph, list item, or table cell as the link because these are directly associated with the link iteself. These descriptions will be most useful to the user if the description of the link precedes the link. (For instance, if you must use ambiguous link text, it is better to put it at the end of the sentence that describes its destination, rather than putting the ambiguous phrase at the beginning of the sentence.) This is because if the description follows the link, there can be confusion and difficulty for screen reader users who are reading through the page in order (top to bottom).

Links with the same destination should have the same descriptions (per Success Criterion 3.2.4), but links with different purposes and destinations should have different descriptions. [LC-497]

Techniques for Addressing Success Criterion 2.4.4

Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this criterion. The techniques listed only satisfy the success criterion if all of the WCAG 2.0 conformance requirements have been met.

Examples of Success Criterion 2.4.4

• A link contains text that gives a description of the information at that URL

  A page contains the sentence "There was much bloodshed during the Medieval period of history." Where "Medieval period of history" is a link.

• A link is preceded by a text description of the information at that URL

  A page contains the sentence "Learn more about the Government of Ireland's Commission on Electronic Voting at Go Vote!" where "Go Vote!" is a link.

• Both an icon and text are included in the same link

  An icon of a voting machine and the text "Government of Ireland's Commission of Electronic Voting" are combined to make a single link. The alt text for the icon is null, since the purpose of the link is already described by the text of the link next to the icon.

• A list of book titles

  A list of books is available in three formats: HTML, PDF, and mp3 (a recording of a person reading the book). To avoid hearing the title of each book three times (once for each format), the first link for each book is the title of the book, the second link says "PDF" and the third says, "mp3."

• News article summaries

  A Web page contains a collection of news articles. The main page lists the first few sentences of each article, followed by a "Read more" link. A screen reader command to read the current paragraph provides the context to interpret the purpose of the link. [LC-497]

Related Resources

Resources are for information purposes only, no endorsement implied.

• Using Link Titles to Help Users Predict Where They Are Going

• WebAIM Techniques for Hypertext Links

Intent of this Success Criterion

The intent of this success criterion is to make it possible for users to locate content in a manner that best meets their needs. Users may find one technique easier or more comprehensible to use than another.

Techniques for Addressing Success Criterion 2.4.5

Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this criterion. The techniques listed only satisfy the success criterion if all of the WCAG 2.0 conformance requirements have been met.

Examples of Success Criterion 2.4.5

• A search mechanism.

  A large food processing company provides a site containing recipes created using its products. The site provides a search mechanism to search for recipes using a particular ingredient. In addition, it provides a list box that lists several categories of foods. A user may type "soup" in to the search engine or may select "soup" from the list box to go to a page with a list of recipes made from the company's soup products

• Links between Web pages.

  A local hair salon has created a Web site to promote its services. The site contains only five Web pages. There are links on each Web page to sequentially move forward or backward through the Web pages. In addition, each Web page contains a list of links to reach each of the other Web pages.

• Where content is a result of a process or task - Funds transfer confirmation.

  An on-line banking site allows fund transfer between accounts via the Web. There is no other way to locate the confirmation of fund transfer until the account owner completes the transfer.

• Where content is a result of a process or task - Search engine results.

  A search engine provides the search results based on user input. There is no other way to locate the search results except to perform the search process itself.

Related Resources

Resources are for information purposes only, no endorsement implied.

(none currently documented)

Intent of this Success Criterion

The intent of this success criterion is to help users understand what information is contained in Web pages and how that information is organized. When headings are clear and descriptive, users can find the information they seek more easily, and they can understand the relationships between different parts of the content more easily. Descriptive labels help users identify specific components within the content. [LC-625]

Techniques for Addressing Success Criterion 2.4.6

Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this criterion. The techniques listed only satisfy the success criterion if all of the WCAG 2.0 conformance requirements have been met.

Examples of Success Criterion 2.4.6

• A news site.

  The home page of a news site lists the headlines for the top stories of the hour. Under each heading are the first 35 words of the story and a link to the full article. Each headline gives a clear idea of the article's subject.

• A guide on how to write well

  A guide on writing contains the following section titles: How To Write Well, Cut Out Useless Words, Identify Unnecessary Words, etc. The section headings are clear and concise and the structure of the information is reflected in the structure of the headings.

• Example 3: Consistent headings in different articles

  A Web site contains papers from a conference. Submissions to the conference are required to have the following organization: Summary, Introduction, [other sections unique to this article], Conclusion, Author Biography, Glossary, and Bibliography. The title of each Web page clearly identifies the article it contains, creating a useful balance between the uniqueness of the articles and the consistency of the section headings.

Related Resources

Resources are for information purposes only, no endorsement implied.

• Methods for Designing Usable Web Sites Methods for collecting, writing, and revising Web content to make it easy to use.

• How Users Read on the Web A study showing that most users scan Web pages rather than reading them word by word.

• Applying Writing Guidelines to Web Pages A report on the effects of making Web sites concise, easy to scan, and objective.

Intent of this Success Criterion

The intent of this success criterion is to provide a way for the user to orient herself within a set of Web pages, a Web site, or a Web application and find related information.

Techniques for Addressing Success Criterion 2.4.7

Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this criterion. The techniques listed only satisfy the success criterion if all of the WCAG 2.0 conformance requirements have been met.

Examples of Success Criterion 2.4.7

• Links to help user determine their location in a site

  A research group is part of an educational department at a university. The group's home page links to the department home page and the university's home page.

• A breadcrumb trail

  A portal Web site organizes topics into categories. As the user navigates through categories and subcategories, a breadcrumb trail shows the current location in the hierarchy of categories. Each page also contains a link to the portal home page.

Related Resources

Resources are for information purposes only, no endorsement implied.

• Breadcrumb Navigation: Further Investigation of Usage

• The Sound of the Accessible Title Tag Separator [LC-575]

Intent of this Success Criterion

The intent of this success criterion is to help users understand the purpose of each link in the content, so they can decide whether they want to follow it. Links with the same destination should have the same descriptions (per Success Criterion 3.2.4), but links with different purposes and destinations should have different descriptions. Because the purpose of a link can be identified from its link text, links can be understood when they are out of context, such as when the user agent provides a list of all the links on a page. [LC-497]

Techniques for Addressing Success Criterion 2.4.8

Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this criterion. The techniques listed only satisfy the success criterion if all of the WCAG 2.0 conformance requirements have been met.

Examples of Success Criterion 2.4.8

• Both an icon and text are included in the same link

  An icon of a voting machine and the text "Government of Ireland's Commission of Electronic Voting" are combined to make a single link.

• A list of book titles

  A list of books is available in three formats: HTML, PDF, and mp3 (a recording of a person reading the book). The title of the book is followed by links to the different formats. The rendered text for each link is just the format type, but the text associated with each link includes the title as well as the format; for instance, "Gulliver's Travels, MP3."

Related Resources

Resources are for information purposes only, no endorsement implied.

• Using Link Titles to Help Users Predict Where They Are Going

• WebAIM Techniques for Hypertext Links

Intent of this Success Criterion

Techniques for Addressing Success Criterion 2.4.9

Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this criterion. The techniques listed only satisfy the success criterion if all of the WCAG 2.0 conformance requirements have been met.

Intent of Guideline 3.1

The intent of this guideline is to allow text content to be read by users and by assistive technology, and to ensure that information necessary for understanding it is available.

People with disabilities experience text in many different ways. For some the experience is visual; for some it is auditory; for some it is tactile; for still others it is both visual and auditory. Some users experience great difficulty in recognizing written words yet understand extremely complex and sophisticated documents when the text is read aloud, or when key processes and ideas are illustrated visually or interpreted as sign language. For some users, it is difficult to infer the meaning of a word or phrase from context, especially when the word or phrase is used in an unusual way or has been given a specialized meaning; for these users the ability to read and understand may depend on the availability of specific definitions or the expanded forms of acronyms or abbreviations. User agents, including speech-enabled as well as graphical applications, may be unable to present text correctly unless the language and direction of the text are identified; while these may be minor problems for most users, they can be enormous barriers for users with disabilities. In cases where meaning cannot be determined without pronunciation information (for example, certain Japanese Kanji, example), pronunciation information must be available as well

Intent of this Success Criterion

The intent of this success criterion is to ensure that content developers provide information in the Web page that user agents need to present text and other linguistic content correctly. Both assistive technologies and conventional user agents can render text more accurately when the language of the Web page is identified. Screen readers can load the correct pronunciation rules. Visual browsers can display characters and scripts correctly. Media players can show captions correctly. As a result, users with disabilities will be better able to understand the content.

The default human language of the Web page is the default text-processing language as discussed in Internationalization Best Practices: Specifying Language in XHTML & HTML Content. When a Web page uses several languages, the default text-processing language is the language which is used most. (If several languages are used equally, the first language used should be chosen as the default human language.) [LC-1376]

Techniques for Addressing Success Criterion 3.1.1

Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this criterion. The techniques listed only satisfy the success criterion if all of the WCAG 2.0 conformance requirements have been met.

Examples of Success Criterion 3.1.1

• Example 1. A Web page with content in two languages

  A Web page produced in Germany includes content in both German and English, but most of the content is in German. The default human language is identified as German (de).

Related Resources

Resources are for information purposes only, no endorsement implied.

• Internationalization Best Practices: Specifying Language in XHTML & HTML Content [LC-1376] [LC-1378]

• d140 Learning to read. 2001. International Classification of Functioning, Disabilities, and Health. World Health Organization

Intent of this Success Criterion

The intent of this success criterion is to ensure that user agents can correctly present content written in multiple languages. This applies to graphical browsers as well as screen readers, braille displays, and other voice browsers.

Both assistive technologies and conventional user agents can render text more accurately if the language of each passage of text is identified. Screen readers can use the pronunciation rules of the language of the text. Visual browsers can display characters and scripts in appropriate ways. This is especially important when switching between languages that read from left to right and languages that read from right to left, or when text is rendered in a language that uses a different alphabet. Users with disabilities who know all the languages used in the Web page will be better able to understand the content when each passage is rendered appropriately.

When no other language has been specified for a phrase or passage of text, its human language is the default human language of the Web page (see Success Criterion 3.1.1). So the human language of all content in single language documents can be programmatically determined.

Individual words or phrases in one language can become part of another language. For example, "rendezvous" is a French word that has been adopted in English, appears in English dictionaries, and is properly pronounced by English screen readers. Hence a passage of English text may contain the word "rendezvous" without specifying that its human language is French and still satisfy this success criterion. Frequently, when the human language of text appears to be changing for a single word, that word has become part of the language of the surrounding text. Because this is so common in some languages, single words are not included in this success criterion. [LC-913] [LC-1296]

Techniques for Addressing Success Criterion 3.1.2

Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this criterion. The techniques listed only satisfy the success criterion if all of the WCAG 2.0 conformance requirements have been met.

Examples of Success Criterion 3.1.2

1. A German phrase in an English sentence.

   In the sentence, "He maintained that the DDR (German Democratic Republic) was just a 'Treppenwitz der Weltgeschichte'," the German phrase 'Treppenwitz der Weltgeschichte' is marked as German. 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. When a screen reader encounters the German phrase, it changes pronunciation rules from English to German to pronounce the word correctly.

Related Resources

Resources are for information purposes only, no endorsement implied.

• Language tags in HTML and XML - W3C Internationalization Working Group

• [LC-1377]

• [LC-1377]

• Internationalization Best Practices: Specifying Language in XHTML & HTML Content [LC-1376]

• d140 Learning to read. 2001. International Classification of Functioning, Disabilities, and Health. World Health Organization

Intent of this Success Criterion

Certain disabilities make it difficult to understand nonliteral word usage and specialized words or usage. Certain disabilities make it difficult to understand figurative language or specialized usage. Providing such mechanisms is vital for these audiences. Specialized information intended for non-specialist readers is encouraged to satisfy this success criterion, even when claiming only Single-A or Double-A conformance. [LC-945]

Techniques for Addressing Success Criterion 3.1.3

Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this criterion. The techniques listed only satisfy the success criterion if all of the WCAG 2.0 conformance requirements have been met.

Examples of Success Criterion 3.1.3

• Text that includes a definition for a word used in an unusual way.

  Organize the list or "cascade" of dictionaries and other resources so that the definition search will find the intended definitions instead of displaying definitions from other sources in the "cascade." (The "cascade" lists the dictionaries and other reference materials in the order most likely to bring up the right definition. This controls the order to follow when searching for definitions.)

• Including definitions in the glossary.

  WCAG 2.0 uses the word "text" in a specific way. Thus, when the word "text" is used within WCAG 2.0 it is linked to the definition of "text" provided in a glossary within the same Web page.

• The specific definition of a word is provided at the bottom of the page.

  The internal link from the word to the corresponding definition is also provided within the page.

Related Resources

Resources are for information purposes only, no endorsement implied.

• Free bilingual dictionaries for a number of languages are available from the Freedict.org Web site. The dictionaries are of uneven quality and size as noted on the site. Retrieved 9 April 2005.

• The WorldStar Free Dictionaries, Translators and Search Engines site provides access to free on-line dictionaries and search engines in many languages. Retrieved 18 November 2005.

• More dictionaries are at your dictionary, freelang.com (in English, Spanish and French!) and many other places.

Intent of this Success Criterion

The intent of this success criterion is to ensure that users can access the expanded form of abbreviations.

Techniques for Addressing Success Criterion 3.1.4

Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this criterion. The techniques listed only satisfy the success criterion if all of the WCAG 2.0 conformance requirements have been met.

Examples of Success Criterion 3.1.4

• A dictionary search form.

  A Web site includes a search form provided by an on-line acronym service. Users enter an acronym and the form returns a list of possible expansions from the sources that it searched.

• A medical Web site.

  A medical Web site provides information for both doctors and patients. The site includes a set of cascading dictionaries; a very specialized medical dictionary is first, followed by a second medical dictionary for the general public. The cascade also includes a list of acronyms and abbreviations that are unique to the site, and finally there is a standard dictionary as well. The standard dictionary at the end of the list provides definitions for most words in the text. The specialized medical dictionary yields definitions of unusual medical terms. Definitions for words that appear in more than one dictionary are listed in the order of the cascade. The meaning of acronyms and abbreviations is provided by the list of acronyms and abbreviations.

• An abbreviation whose expansion is provided the first time the abbreviation appears in the content.

  The name, "World Wide Web Consortium," appears as the first heading on the organization's home page. The abbreviation, "W3C," is enclosed in parentheses in the same heading.

• Expanded forms of Abbreviations.

  The expanded form of each abbreviation is available in a programmatically determinable manner. User agents that speak the text can use the expanded form to announce the abbreviation. Other user agents might make the expanded form available as a tooltip or as contextual help for the abbreviation. [LC-915]

Related Resources

Resources are for information purposes only, no endorsement implied.

• Acronym finder - You can search with the exact acronym, the beginning of the acronym, wildcards and reverse lookup.

• The Opaui Guide to Lists of Acronyms, Abbreviations, and Initialisms on the World Wide Web.

• AbbreviationZ - The A to Z of Acronyms & Abbreviations on the Net.

Intent of this Success Criterion

Content should be written as clearly and simply as possible. [LC-569] [LC-887] The intent of this success criterion is:

• to ensure that additional content is available to aid the understanding of difficult or complex text;

• to establish a testable measure indicating when such additional content is required.

This success criterion helps people with reading disabilities while also allowing authors to publish difficult or complex Web content. Text difficulty is described in terms of the level of education required to read the text. Education levels are defined according to the International Standard Classification of Education [UNESCO], which was created to allow international comparison among systems of education.

Difficult or complex text may be appropriate for most members of the intended audience (that is, most of the people for whom the content has been created). But there are people with disabilities, including reading disabilities, even among highly educated users with specialized knowledge of the subject matter. It may be possible to accommodate these users by making the text more readable. If the text cannot be made more readable, then supplemental content is needed. Supplemental content is required when text demands reading ability more advanced than the lower secondary education level—that is, more than nine years of school. Such text presents severe obstacles to people with reading disabilities and is considered difficult even for people without disabilities who have completed upper secondary education.

Reading disabilities such as dyslexia make it difficult to recognize written or printed words and associate them with the correct sounds. This is called "decoding" the text. Decoding must be automatic in order for people to read fluently. The act of decoding text word by word consumes much of the mental energy that most people are able to use for understanding what they read. [LC-542] Text that uses short, common words and short sentences is easier to decode and usually requires less advanced reading ability than text that uses long sentences and long or unfamiliar words.

The education level required to read text content (also called "readability") is measured by analyzing selected passages of text from the Web page. If the Web page includes text written for different purposes or different styles are used, the selected passages include samples of the types of content in the Web page and the different styles in which the content is written. (In many cases, the Web page contains only one kind of text content—e.g., technical documentation, a legal notice, marketing material, etc.—and all the content uses the same style.)

Educators can also measure the education level required to read text content. For example, qualified teachers can evaluate text according to local education standards to determine if it requires reading ability beyond what is expected for students in the last year of lower secondary education.

When a web page contains multiple languages, a readability result should be calculated for each language that constitutes at least 5% of the content and that is used in full sentences or paragraphs (not just individual words or phrases). The overall readability of the page should be judged on the language that yields the worst readability results. [LC-1535]

The readability of content may also be determined by applying a readability formula to the selected passage. Many (though not all) readability formulas base their calculations on passages of 100 words. Such formulas have been developed for many languages. The number of words in the passage is counted and the length of the words is determined by counting either the number of syllables or the number of characters. Most readability formulas also count the number and length of sentences. The average length of words and sentences in the content is then used to calculate a readability score. (Some languages, such as Japanese, may include multiple scripts within the same passage. Readability formulas for these languages may use the number and length of such "runs" in their calculations.) The result may be presented as a number (for example, on a scale from 0-100) or as a grade level. These results can then be interpreted using the education levels described in the International Standard Classification of Education.

Adapted from International Standard Classification of Education [UNESCO]

Techniques for Addressing Success Criterion 3.1.5

Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this criterion. The techniques listed only satisfy the success criterion if all of the WCAG 2.0 conformance requirements have been met.

Examples of Success Criterion 3.1.5

1. A scientific journal including readable summaries of complex research articles

   A scientific journal includes articles written in highly technical language aimed at specialists in the field. The journal's Table of Contents page includes a plain-language summary of each article. The summaries are intended for a general audience with eight years of school. The metadata for the journal uses the Dublin Core specification to identify the education level of the articles' intended audience as "advanced," and the education level of the intended audience for the summaries as "lower secondary education."

2. Medical information for members of the public.

   A medical school operates a Web site that explains recent medical and scientific discoveries. The articles on the site are written for people without medical training. Each article uses the Dublin Core metadata specification to identify the education level of the intended audience as "lower secondary education" and includes the Flesch Reading Ease score for the article. A link on each page displays the education level and other metadata. No supplemental content is required because people who read at the lower secondary education level can read the articles.

3. An e-learning application.

   An on-line course about Spanish cultural history includes a unit on Moorish architecture. The unit includes text written for students with different reading abilities. Photographs and drawings of buildings illustrate architectural concepts and styles. Graphic organizers are used to illustrate complex relationships, and an audio version using synthetic speech is available. The metadata for each version describes the academic level of the content and includes a readability score based on formulas developed for Spanish-language text. The learning application uses this metadata and metadata about the students to provide versions of instructional content that match the needs of individual students.

4. Science information that requires a reading ability at the lower secondary education level.

   The paragraphs below (114 words total) require a reading ability of grade 6.9 in the United States according to the Flesch-Kinkaid formula. In the US, grade 6.9 is at the lower secondary education level.

   In a dazzling and dramatic portrait painted by the Sun, the long thin shadows of Saturn's rings sweep across the planet's northern latitudes. Within the shadows, bright bands represent areas where the ring material is less dense, while dark strips and wave patterns reveal areas of denser material.

   The shadow darkens sharply near upper right, corresponding to the boundary of the thin C ring with the denser B ring. A wide-field, natural color view of these shadows can be seen here.

   The globe of Saturn's moon Mimas (398 kilometers, or 247 miles across) has wandered into view near the bottom of the frame. A few of the large craters on this small moon are visible.

   (Source: NASA - Sun-striped Saturn)

Related Resources

Resources are for information purposes only, no endorsement implied.

• A Plain Language Audit Tool provides a checklist for determining whether documents can be edited for clarity and "plain language." The checklist includes a readability assessment. Available from the Northwest Territories (Canada) Literacy Council at http://www.nwt.literacy.ca/plainlng/auditool/cover.htm.

• The Plain Language Network Web site provides many useful resources to help writers produce documents that communicate clearly in a variety of cultural and rhetorical contexts. Refer to: http://www.plainlanguagenetwork.org/.

• The US Government's plain language Web site provides general information about plain language as well as information about use of plain language in US Government documents, including legal requirements

• The Plain English Campaign Web site provides useful information and guidance for authors writing in English.

• Juicy Studio's Readability Test analyses the readability of all rendered content. [LC-1125]

• Hall, T., and Strangman, N. CAST: Graphic organizers. Retrieved 5 April 2005. This article illustrates several different kinds of graphic organizers, explains how each type may be useful, and summarizes research findings that graphic organizers support learning, especially among students with learning disabilities.

• Entry for Audience Education Level. Using Dublin Core – Dublin Core Qualifiers

• IMS Learner Information Packaging Model Information Specification, Table 6.3 "accessibility" learner information data structure detailed description

• TextQuest.de lists references for readability formulas for different languages, including English, German, Spanish, Dutch, French, and Swedish. [LC-1381]

• Richtlijnen Keurmerk Makkelijk Lezen are the guidelines used by the Stichting Makkelijk Lezen (Easy Reading Foundation). [LC-1381]

• Leesbaar Nederlands ("Readable Dutch") contains guidelines for writing text that is accessible for people with a reading disability. These guidelines address language, content and design. [LC-1381]

• Wetenschappelijke verantwoording van de toetsserie Leestechniek & Leestempo describes the CILT (CITO index voor leestechniek - CITO index for reading ability), the formulas developed by the Dutch organization CITO that relate readability to education level. [LC-1381]

• d166 Reading 2001. International Classification of Functioning, Disabilities, and Health. World Health Organization. See also b16701 Reception of written language: mental functions of decoding written messages to obtain their meaning

Intent of this Success Criterion

The intent of this success criterion is to help people who are blind, people who have low vision, and people with reading disabilities to understand content in cases where meaning depends on pronunciation. Often words or characters have different meanings, each with its own pronunciation. The meaning of such words or characters can usually be determined from the context of the sentence. However, for more complex or ambiguous sentences, or for some languages, the meaning of the word cannot be easily determined or determined at all without knowing the pronunciation. When the sentence is read aloud and the screen reader reads the word using the wrong pronunciation, it can be even more difficult to understand than when read visually. When words are ambiguous or indeterminate unless the pronunciation is known, then providing some means of determining the pronunciation is needed.

For example, in the English language heteronyms are words that are spelled the same but have different pronunciations and meanings, such as the words desert (abandon) and desert (arid region). [LC-543] Additionally, in some languages certain characters can be pronounced in different ways. In Japanese, for example, there are characters like Han characters(Kanji) that have multiple pronunciations. Screen readers may speak the characters incorrectly without the information on pronunciation. When read incorrectly, the content will not make sense to users.

Techniques for Addressing Success Criterion 3.1.6

Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this criterion. The techniques listed only satisfy the success criterion if all of the WCAG 2.0 conformance requirements have been met.

Examples of Success Criterion 3.1.6

• Giving the reading of a person's name.

  Web content in Japanese provides kana (Japanese phonetic syllabary characters) written next to Han characters (Kanji) show the pronunciation of a person's name. The kana is provided to users in parentheses right after the word. Giving the reading of the words written in Han characters (Kanji) allows both sighted users and screen readers to read/pronounce the words correctly. Note that screen readers will speak the word twice: the Han characters (Kanji) that can be pronounced in a wrong way are read first and then kana is spoken in order to provide the correct reading.

• Showing the reading of the words by ruby element.

  Web content using XHTML 1.1 provides kana (phonetic syllabary characters) written above the characters to show the reading (pronunciation) of the words by using the ruby element.

• Providing sound files of the pronunciation.

  A document includes some words whose meaning cannot be determined without knowing the correct pronunciation. Each word is linked to a sound file that gives the correct pronunciation. Users can select these links to find out how to pronounce the words.

• Including pronunciation information in the glossary.

  A Web page includes a glossary section. Some items in the glossary include pronunciation information as well as definitions. Words in the content whose meaning cannot be determined without knowing their pronunciation are linked to the appropriate entries in the glossary.

• Text that includes pronunciation information for characters shared by several languages but pronounced differently in each language

  A Japanese university Web site includes several short phrases quoted from scholarly texts in Chinese and Korean. The quotations are written using the same script as the Japanese text. Pronunciation information is provided to show the correct reading of the Chinese and Korean characters.

Related Resources

Resources are for information purposes only, no endorsement implied.

(none currently documented)

Intent of Guideline 3.2

The intent of this success criterion is to help users with disabilities by presenting content in a predictable order from Web page to Web page and by making the behavior of functional and interactive components predictable. It is difficult for some users to form an overview of the Web page: screen readers present content as a one-dimensional stream of synthetic speech that makes it difficult to understand spatial relationships. Users with cognitive limitations may become confused if components appear in different places on different pages.

To give just a few examples, people who use screen magnifiers see only part of the screen at any point in time; a consistent layout makes it easier for them to find navigation bars and other components. Placing repeated components in the same relative order within a set of Web pages allows users with reading disabilities to focus on an area of the screen rather than spending additional time decoding the text of each link. Users with limited use of their hands can more easily determine how to complete their tasks using the fewest keystrokes; and so on.

Intent of this Success Criterion

The intent of this success criterion is to ensure that functionality is predictable as visitors navigate their way through a document. Any component that is able to trigger an event when it receives focus must not change the context. Examples of changing context when a component receives focus include, but are not limited to:

• forms submitted automatically when a component receives focus;

• new windows launched when a component receives focus;

• focus is changed to another component when that component receives focus;

Techniques for Addressing Success Criterion 3.2.1

Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this criterion. The techniques listed only satisfy the success criterion if all of the WCAG 2.0 conformance requirements have been met.

Examples of Success Criterion 3.2.1

• Example 1: A dropdown menu

  A dropdown menu on a page allows users to choose between jump destinations. If the person uses the keyboard to move down to a choice and activates it (with a spacebar or enter key) it will jump to a new page. However, if the person moves down to a choice and either hits the escape or the tab key to move out of the pulldown menu – it does not jump to a new screen as the focus shifts out of the dropdown menu.

• Example of a Failure: A help dialog

  When a field receives focus, a help dialog describing the field opens. As a keyboard user tabs through the Web page, the dialog opens every time the user attempts to tab past the field. [LC-1130]

Intent of this Success Criterion

The intent of this success criterion is to ensure that entering data or selecting from a control has predictable effects. Changes in context, such as changing the input fields based on the value of a radio button, can confuse users who do not easily perceive the change or are easily distracted by changes. Changes of context are appropriate only when it is clear that such a change will happen when a field is selected or a button is pressed.

Techniques for Addressing Success Criterion 3.2.2

Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this criterion. The techniques listed only satisfy the success criterion if all of the WCAG 2.0 conformance requirements have been met.

Examples of Success Criterion 3.2.2

• A form is provided for creating calendar entries in a web based calendaring and scheduling application. Along with the standard fields for subject, time and location, there is a set of radio buttons to select the type of calendar entry to create. The calendar entry type can be meeting, appointment or reminder. If the user selects the radio for meeting, additional fields are displayed on the page for entering the meeting participants. Different fields appear if the reminder button is chosen. Because only parts of the entry change and the overall structure remains the same the basic context remains for the user. Instructions at the beginning of the Web page explain the behavior of each radio button and the fields that appear when the button is selected.

• A tab panel user interface is implemented within a Web page. The tab panel consists of 5 tabs, each with a different title and content: US News, World News, Weather, Entertainment, and Humor. As the user navigates from tab to tab using the arrow keys, the contents of the Web page are updated to reflect the selected tab. For example, when the user navigates to the Humor tab, A short account of a humorous incident is made visible in the tab panel, replacing the previous contents of the panel. This is the expected behavior of a tab panel user interface. The tab key can be used to navigate within the elements of the tab panel and then to other elements on the page below the current panel.

• A form contains fields representing US phone numbers. All of the numbers have a three digit area code followed by a three digit prefix and finally a four digit number, and each part of the phone number is entered into a separate field. When the user completes the entry of one field and enter the first digit of the next field, the focus automatically moves to the next field of the phone number. This behavior of phone fields is described for the user at the beginning of the form. [LC-755] [LC-1299]

Intent of this Success Criterion

The intent of this success criterion is to encourage the use of consistent presentation and layout for users who interact with repeated content within [LC-983] a set of Web pages and need to locate specific information or functionality more than once. Individuals with low vision who use screen magnification to display a small portion of the screen at a time often use visual cues and page boundaries to quickly locate repeated content. Presenting repeated content in the same order is also important for visual users who use spatial memory or visual cues within the design to locate repeated content.

It is important to note that the use of the phrase "same order" in this section is not meant to imply that subnavigation menus cannot be used or that blocks of secondary navigation or page structure cannot be used. Instead, this success criterion is intended to assist users who interact with repeated content across Web pages to be able to predict the location of the content they are looking for and find it more quickly when they encounter it again.

Users may initiate a change in the order by using adaptive user agents or by setting preferences so that the information is presented in a way that is most useful to them. [LC-612] [LC-612]

Techniques for Addressing Success Criterion 3.2.3

Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this criterion. The techniques listed only satisfy the success criterion if all of the WCAG 2.0 conformance requirements have been met.

Examples of Success Criterion 3.2.3

• A consistently located control

  A search field is the last item on every Web page in a site. users can quickly locate the search function.

• An expanding navigation menu

  A navigation menu includes a list of seven items with links to the main sections of a site. When a user selects one of these items, a list of subnavigation items is inserted into the top-level navigation menu.

• Consistently positioned skip navigation controls

  A "skip navigation" link is included as the first link on every page in a Web site. The link allows users to quickly bypass heading information and navigational content and begin interacting with the main content of a page.

• Skip to navigation link

  A skip to navigation link is provided to navigational content at the end of a page. The link is consistently located at the top of each page so that keyboard users can easily locate it when needed.

Related Resources

Resources are for information purposes only, no endorsement implied.

• Detweiler, M.C. and Omanson, R.C. (1996), Ameritech Web Page User Interface Standards and Design Guidelines.

• Understanding disability issues when designing Web sites.

Intent of this Success Criterion

The intent of this success criterion is to ensure consistent identification of functional components that appear repeatedly within a set of Web pages. A strategy that people who use screen readers use when operating a Web site is to rely heavily on their familiarity with functions that may appear on different Web pages. If identical functions have different labels on different Web pages, the site will be considerably more difficult to use. It may also be confusing and increase the cognitive load for people with cognitive limitations. Therefore, consistent labeling will help.

This consistency extends to the text alternatives. If icons or other non-text items have the same functionality, then their text alternatives should be consistent as well.

Techniques for Addressing Success Criterion 3.2.4

Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this criterion. The techniques listed only satisfy the success criterion if all of the WCAG 2.0 conformance requirements have been met.

Examples of Success Criterion 3.2.4

• Example 1: Document Icon

  A document icon is used to indicate document download throughout a site. The text alternative for the icon always begins with the word “Download,” followed by a shortened form of the document title. Using different text alternatives to identify document names for different documents is a consistent use of text alternatives.

• Example 2: Check Mark

  A check mark icon functions as "approved", on one page but as "included" on another. Since they serve different functions, they have different text alternatives.

• Example 3: Consistent references to other pages

  A Web site publishes articles online. Each article spans multiple Web pages and each page contains a link to the first page, the next page and the previous page of the article. If the references to the next page read "page 1", "page 2", "page 2" etcetera, the labels are not the same but they are consistent. Therefore, these references are not failures of this success criterion.

• Example 4: Icons with similar functions

  An e-commerce application uses a printer icon that allows the user to print receipts and invoices. In one part of the application, the printer icon is labeled "Print receipt" and is used to print receipts, while in another part it is labeled "Print invoice" and is used to print invoices. The labeling is consistent ("Print x"), but the labels are different to reflect the different functions of the icons. Therefore, this example does not fail the success criterion.

• Example 5: Save icon

  A common "save" icon is used through out the site where page save function is provided on multiple Web pages.

• Example 6: Example of a Failure

  A submit "search" button on one Web page and a "find" button on another Web page both have a field to enter a term and list topics in the Web site related to the term submitted. In this case, the buttons have the same functionality but are not labeled consistently.

Intent of this Success Criterion

The intent of this success criterion is to encourage design of Web content that gives users full control of changes of context. This success criterion aims to eliminate potential confusion that may be caused by unexpected changes of context such as automatic launching of new windows, automatic submission of forms after selecting an item from a list, etcetera. Such unexpected changes of context may cause difficulties for people with motor impairments, people with low vision, people who are blind, and people with certain cognitive limitations.

Techniques for Addressing Success Criterion 3.2.5

Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this criterion. The techniques listed only satisfy the success criterion if all of the WCAG 2.0 conformance requirements have been met.

Examples of Success Criterion 3.2.5

• an "update now" button

  Instead of automatically updating the content, the author provides an "Update now" button that requests a refresh of the content.

• An automatic redirection

  A user is automatically redirected from an old page to a new page in such a way that he or she never realizes the redirect has occurred.

Related Resources

Resources are for information purposes only, no endorsement implied.

• Use standard redirects: don't break the back button! (W3C QA Tip).

• HTTP/1.1 Status Code Definitions: Redirection 3xx.

Intent of Guideline 3.3

Everyone makes mistakes. However, people with some disabilities have more difficulty creating error-free input. In addition, it may be harder for them to detect that they have made an error. Typical error indication methods may not be obvious to them because of a limited field of view, limited color perception, or use of assistive technology. This guideline seeks to reduce the number of serious or irreversible errors that are made, increase the likelihood that all errors will be detected, and help users understand what they should do to correct an error.

Intent of this Success Criterion

The intent of this success criterion is to ensure that users are aware that an error has occurred and can determine what is wrong. The error message should be as specific as possible. [LC-979] In the case of an unsuccessful form submission, re-displaying the form and indicating the fields in error is insufficient for some users to perceive that an error has occurred. Screen reader users, for example, will not know there was an error until they encounter one of the indicators. They may abandon the form altogether before encountering the error indicator, thinking that the page simply is not functional.

The identification and description of an error can be combined with programmatic information that user agents or assistive technologies can use to identify an error and provide error information to the user. For example, certain technologies can specify that the user's input must not fall outside a specific range, or that a form field is required. Currently, few technologies support this kind of programmatic information, but the success criterion does not require, nor prevent it. [LC-629]

Techniques for Addressing Success Criterion 3.3.1

Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this criterion. The techniques listed only satisfy the success criterion if all of the WCAG 2.0 conformance requirements have been met.

Examples of Success Criterion 3.3.1

• Identifying errors in a form submission

  An airline Web site offers a special promotion on discounted flights. The user is asked to complete a simple form that asks for personal information such as name, address, phone number, seating preference and e-mail address. If any of the fields of the form are either not completed or completed incorrectly, an alert is displayed notifying the user which field or fields were missing or incorrect. [LC-1116]

  Note: This success criterion does not mean that color or text styles cannot be used to indicate errors. It simply requires that errors also be identified using text. In this example, two asterisks are used in addition to color.

• Providing multiple cues

  The user fails to fill in two fields on the form. In addition to describing the error and providing a unique character to make it easy to search for the fields, the fields are highlighted in yellow to make it easier to visually search for them as well.

Related Resources

Resources are for information purposes only, no endorsement implied.

• d3151 Communicating with - receiving - general signs and symbols. International Classification of Functioning, Disability and Health. 2001. World Health Organization.

Intent of this Success Criterion

The intent of this success criterion is to ensure that users receive appropriate suggestions for correction of an input error if it is possible.

Success Criterion 3.3.1 provides for notification of errors. However, persons with cognitive limitations may find it difficult to understand how to correct the errors. People with visual disabilities may not be able to figure out exactly how to correct the error. In the case of an unsuccessful form submission, users may abandon the form because although they may be aware that an error has occurred, they may be unsure of how to correct the error even though they are aware that it has occurred.

The content author may provide the description of the error, or the user agent may provide the description of the error based on technology-specific, programmatically determined information. [LC-630]

Techniques for Addressing Success Criterion 3.3.2

Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this criterion. The techniques listed only satisfy the success criterion if all of the WCAG 2.0 conformance requirements have been met.

Examples of Success Criterion 3.3.2

• Additional Help for Correcting An Input Error

  The result of a form that was not successfully submitted describes an input error in place in the page along with the correct input and offers additional help for the form field that caused the input error. [LC-1118]

• Suggestions from a Limited Set of Values

  An input field requires that a month name be entered. If the user enters "12," suggestions for correction may include

  • A list of the acceptable values, e.g., "Choose one of: January, February, March, April, May, June, July, August, September, October, November, December."

  • A description of the set of values, e.g., "Please provide the name of the month."

  • The conversion of the input data interpreted as a different month format, e.g., "Do you mean 'December'?"

Related Resources

Resources are for information purposes only, no endorsement implied.

(none currently documented)

Intent of this Success Criterion

The intent of this success criterion is to help users with disabilities avoid serious consequences as the result of a mistake when performing an action that cannot be reversed. For example, purchasing non-refundable airline tickets or submitting an order to purchase stock in a brokerage account are financial transactions with serious consequences. If a user has made a mistake on the date of air travel, he or she could end up with a ticket for the wrong day that cannot be exchanged. If the user made a mistake on the number of stock shares to be purchased, he or she could end up purchasing more stock than intended. Both of these types of mistakes involve transactions that take place immediately and cannot be altered afterwards, and can be very costly. Likewise, it may be an unrecoverable error if users unintentionally modify or delete data stored in a database that they later need to access, such as their travel profile in a travel services Web site. Test data is included in this provision because, in order for tests to be valid, users are not allowed to modify their answers once submitted; so users need to be able to ensure that their submission is correct.

Users with disabilities may be more likely to make mistakes. People with reading disabilities may transpose numbers and letters, and those with motor disabilities may hit keys by mistake. Providing the ability to reverse actions allows users to correct a mistake that could result in serious consequences. Providing the ability to review and correct information gives the user an opportunity to detect a mistake before taking an action that has serious consequences.

User-controllable data is data that is intended to be accessed by users. (e.g., name and address for the user’s account.) It does not refer such things as internet logs and search engine monitoring data.

Techniques for Addressing Success Criterion 3.3.3

Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this criterion. The techniques listed only satisfy the success criterion if all of the WCAG 2.0 conformance requirements have been met.

Examples of Success Criterion 3.3.3

• Order confirmation.

  A Web retailer offers on-line shopping for customers. When an order is submitted, the order information—including items ordered, quantity of each ordered item, shipping address, and payment method—are displayed so that the user can inspect the order for correctness. The user can either confirm the order or make changes.

Related Resources

Resources are for information purposes only, no endorsement implied.

(none currently documented)

Intent of this Success Criterion

The intent of this success criterion is to help users avoid making mistakes when their input is required. To help avoid mistakes it is good user interface design to provide simple instructions and cues for entering information. Some users with disabilities may be more likely to make mistakes than users without disabilities or recovery from mistakes may be more difficult, making mistake avoidance an important strategy for users with disabilities. People with disabilities rely on well documented forms and procedures to interact with a page. Blind users need to know exactly what information should be entered into form fields and what the available choices are. Simple instructions visually connected to form controls can assist users with cognitive disabilities or those accessing a page using a screen magnifier.

The intent of this success criterion is not to clutter the page with unnecessary information but to provide important cues and instructions that will benefit people with disabilities. Too much information or instruction can be just as much of a hindrance as too little. The goal is to make certain that enough information is provided for the user to accomplish the task without undue confusion or navigation.

Techniques for Addressing Success Criterion 3.3.4

Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this criterion. The techniques listed only satisfy the success criterion if all of the WCAG 2.0 conformance requirements have been met.

Examples of Success Criterion 3.3.4

• A field which requires the user to enter the two character abbreviation for a US state has a link next to it which will popup an alphabetized list of state names and the correct abbreviation.

• A field for entering a date contains initial text which indicates the correct format for the date.

• A field for entering a given name is clearly labeled with "Given Name" and the field for family name is labeled "Family Name" to avoid confusion over which name is requested.

Related Resources

Resources are for information purposes only, no endorsement implied.

(none currently documented)

Intent of this Success Criterion

The intent of this success criterion is to help users avoid making mistakes. Some users with disabilities may be more likely to make mistakes than users without disabilities. Using context-sensitive help, users find out how to perform an operation without losing track of what they are doing.

Context-sensitive help only needs to be provided when the label is not sufficient to describe all functionality. In most cases, context-sensitive help should not be placed in the form itself, but should instead be available to users when they request it (e.g. by linking to a separate help file). [LC-757]

The content author may provide the help text, or the user agent may provide the help text based on technology-specific, programmatically determined information. [LC-632]

Techniques for Addressing Success Criterion 3.3.5

Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this criterion. The techniques listed only satisfy the success criterion if all of the WCAG 2.0 conformance requirements have been met.

Examples of Success Criterion 3.3.5

• Online job application

  Some of the questions may be hard for new job seekers to understand. A help link next to each question provides instructions and explanations for each question.

Related Resources

Resources are for information purposes only, no endorsement implied.

(none currently documented)

Intent of this Success Criterion

The intent of this success criterion is to help users with disabilities avoid consequences that may result from making a mistake when submitting form data. This criterion builds on Success Criterion 3.3.3 in that it applies to all forms that require users to submit information.

Users with disabilities may be more likely to make mistakes and may have more difficulty detecting or recovering from mistakes. People with reading disabilities may transpose numbers and letters, and those with motor disabilities may hit keys by mistake. Providing the ability to reverse actions allows users to correct a mistake that could result in serious consequences. Providing the ability to review and correct information gives the user an opportunity to detect a mistake before taking an action.

Techniques for Addressing Success Criterion 3.3.6

Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this criterion. The techniques listed only satisfy the success criterion if all of the WCAG 2.0 conformance requirements have been met.

Intent of Guideline 4.1

The purpose of this guideline is to support compatibility with current and future user agents, especially assistive technologies (AT). This is done both by 1) ensuring that authors do not do things that would break AT (e.g. poorly formed markup) or circumvent AT (e.g. by using unconventional markup or code) and 2) exposing information in the content in standard ways that assistive technologies can recognize and interact with. Since technologies change quickly, and AT developers have much trouble keeping up, it is important that content follow conventions and be compatible with APIs so that AT can more easily work with new technologies as they evolve.

Intent of this Success Criterion

The intent of this success criterion is to ensure that user agents, including assistive technologies, can accurately interpret and parse content. If the content cannot be parsed into a data structure, then different user agents may present it differently or be completely unable to parse it. Some user agents use "repair techniques" to render poorly coded content.

Since repair techniques vary among user agents, authors can not assume that content will be accurately parsed into a data structure or that it will be rendered correctly by specialized user agents, including assistive technologies, unless the content us created according to the rules defined in the formal grammar for that technology. Therefore, the success criterion requires that the content can be parsed using only the rules of the formal grammar. [LC-910]

Techniques for Addressing Success Criterion 4.1.1

Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this criterion. The techniques listed only satisfy the success criterion if all of the WCAG 2.0 conformance requirements have been met.

Examples of Success Criterion 4.1.1

Related Resources

Resources are for information purposes only, no endorsement implied.

(none currently documented)

Intent of this Success Criterion

The intent of this success criterion is to ensure that Assistive Technologies (AT) can gather information about, activate(or set) and keep up to date on the status of user interface controls in the content.

When standard controls from accessible technologies are used, this process is straightforward. If the user interface elements are used according to specification the conditions of this provision will be met. (see examples of success criterion 4.1.2 below)

If custom controls are created, however, or interface elements are programmed (in code or script) to have a different role and/or function than usual, then additional measures need to be taken to ensure that the controls provide important information to assistive technologies and allow themselves to be controlled by assistive technologies.

Techniques for Addressing Success Criterion 4.1.2

Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this criterion. The techniques listed only satisfy the success criterion if all of the WCAG 2.0 conformance requirements have been met.

Examples of Success Criterion 4.1.2

• 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.

Related Resources

Resources are for information purposes only, no endorsement implied.

• Access Mozilla: Accessible DHTML

• Dynamic Accessible Web Content Roadmap

• Role Taxonomy for Accessible Adaptable Applications

• States and Adaptable Properties Module

• Microsoft Active Accessibility, Version 2.0

• IBM Guidelines for Writing Accessible Applications using 100% Pure Java

• Flash 8 Accessibility