Understanding WCAG 2.0

Text Alternatives:
Understanding Guideline 1.1

Guideline 1.1: Provide text alternatives for any non-text content so that it can be changed into other forms people need, such as large print, braille, speech, symbols or simpler language

Non-text Content:
Understanding SC 1.1.1

1.1.1 Non-text Content: All non-text content has a text alternative that presents equivalent information, except for the situations listed below. (Level A)

• Controls, Input: If it is a control or accepts user input, then it has a name that describes its purpose. (See also Guideline 4.1.)

• Media, Test, Sensory: If it is (1) synchronized media, (2) live audio-only or live video-only content, (3) a test or exercise that must be presented in non-text format, (4) primarily intended to create a specific sensory experience, then text alternatives at least provide descriptive identification of the non-text content , or (5) a media alternative to text that is clearly labeled as such . (For synchronized media, see also Guideline 1.2.)

  Note: Prerecorded audio-only and video-only files would be covered under Success Criterion 1.1.1, which requires text alternatives that present equivalent information.

• CAPTCHA: If it is to confirm that content is being accessed by a person rather than a computer, then text alternatives that identify and describe the purpose of the non-text content are provided, and alternative forms of CAPTCHA using output modes for different types of sensory perception are provided to accommodate different disabilities.

• Decoration, Formatting, Invisible: If it is pure decoration, or used only for visual formatting, or if it is not presented to users, then it is implemented in a way that it can be ignored by assistive technology.

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.

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.

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.

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".

10. Different alternatives for an image of the world: An image of the world that is used on a travel site as a link to the International Travel section has the text alternative "International Travel". The same image is used as a link on a university Web site with the text alternative "International Campuses".

Techniques and Failures for Success Criterion 1.1.1 [Non-text Content]

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

Key Terms

assistive technology (as used in this document)

hardware and/or software that acts as a user agent, or along with a mainstream user agent, to provide functionality to meet the requirements of users with disabilities that go beyond those offered by mainstream user agents

Note 1: functionality provided by assistive technology includes alternative presentations (e.g., as synthesized speech or magnified content), alternative input methods (e.g., voice), additional navigation or orientation mechanisms, and content transformations (e.g., to make tables more accessible).

Note 2: Assistive technologies often communicate data and messages with mainstream user agents by using and monitoring APIs.

Note 3: The distinction between mainstream user agents and assistive technologies is not absolute. Many mainstream user agents provide some features to assist individuals with disabilities. The basic difference is that mainstream user agents target broad and diverse audiences that usually include people with and without disabilities. Assistive technologies target narrowly defined populations of users with specific disabilities. The assistance provided by an assistive technology is more specific and appropriate to the needs of its target users. The mainstream user agent may provide important functionality to assistive technologies like retrieving Web content from program objects or parsing markup into identifiable bundles.

Example: Examples of assistive technologies that are important in the context of this document include the following:

• screen magnifiers, and other visual reading assistants, which are used by people with visual, perceptual and physical print disabilities to change text font, size, spacing, color, synchronization with speech, etc. in order to improve the visual readability of rendered text and images;

• screen readers, which are used by people who are blind to read textual information through synthesized speech or braille;

• text-to-speech software, which is used by some people with cognitive, language, and learning disabilities to convert text into synthetic speech;

• voice recognition software, which may be used by people who have some physical disabilities;

• alternative keyboards, which are used by people with certain physical disabilities to simulate the keyboard (including alternate keyboards that use head pointers, single switches, sip/puff and other special input devices.);

• alternative pointing devices, which are used by people with certain physical disabilities to simulate mouse pointing and button activations.

CAPTCHA

initialism for "Completely Automated Public Turing test to tell Computers and Humans Apart"

Note 1: CAPTCHA tests often involve asking the user to type in text that is displayed in an obscured image or audio file.

Note 2: A Turing test is any system of tests designed to differentiate a human from a computer. It is named after famed computer scientist Alan Turing. The term was coined by researchers at Carnegie Mellon University. [CAPTCHA]

live audio-only

a time-based live presentation that contains only audio (no video and no interaction)

live video-only

a time-based live presentation that contains only video (no audio and no interaction)

media alternative to text

media that presents no more information than is already presented in text (directly or via text alternatives)

Note: A media alternative to text is provided for those who benefit from alternate representations of text. Media alternatives to text may be audio-only, video-only (including sign-language video), or audio-video.

must be presented in non-text format

would be invalid if presented in text

Example: Color blindness test, hearing test, vision exercise, spelling test.

name

text by which software can identify a component within Web content to the user

Note 1: The name may be hidden and only exposed by assistive technology, whereas a label is presented to all users. In many (but not all) cases, the label and the name are the same.

Note 2: This is unrelated to the name attribute in HTML.

non-text content

any content that is not a sequence of characters that can be programmatically determined or where the sequence is not expressing something in human language

Note: This includes ASCII Art (which is a pattern of characters), emoticons, leetspeak (which is character substitution), and images representing text .

pure decoration

serving only an aesthetic purpose, providing no information, and having no functionality

Note: Text is only purely decorative if the words can be rearranged or substituted without changing their purpose.

Example: The cover page of a dictionary has random words in very light text in the background.

specific sensory experience

a sensory experience that is not purely decorative and does not primarily convey important information or perform a function

Example: Examples include a performance of a flute solo, works of visual art etc.

synchronized media

audio or video synchronized with another format for presenting information and/or with time-based interactive components

text alternative

programmatically determined text that is used in place of non-text content, or text that is used in addition to non-text content and referred to from the programmatically determined text

Example: An image of a chart is described in text in the paragraph after the chart. The short text-alternative for the chart indicates that a description follows.

---

Live Audio-only:
Understanding SC 1.1.2

1.1.2 Live Audio-only: All live audio-only content has a text alternative (Level AAA)

Examples of Success Criterion 1.1.2

• A public relations firm uses Web based caption services to cover live events; the output from the service is incorporated in a sub frame of the Web page which includes the streaming audio control.

• A live radio play of a fringe theatre group is being broadcast to the Web. As the actors stick largely to a set script, and the budget for the program is small, the producers provide a link (with the playwright’s permission) to the script of the play.

• A streaming audio server uses a media format which can also accommodate text and graphics, such as Flash or Silverlight. A stenographer is used to create live captions at an event, and these are mixed on the fly to produce live captions in the media stream which can be viewed by the media player.

• A CEO is to give a press release by telephone to the media in response to a breaking news story, the audio is being recorded and streamed over the internet, but due to time constraints a Web captioning service cannot be set up in time. As the press release is a set statement which the CEO will be reading out, the company simultaneously provides the transcript of the release.

Techniques and Failures for Success Criterion 1.1.2 [Live Audio-only]

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

---

Synchronized Media:
Understanding Guideline 1.2

Guideline 1.2: Provide synchronized alternatives for synchronized media

Captions (Prerecorded):
Understanding SC 1.2.1

1.2.1 Captions (Prerecorded): Captions are provided for prerecorded synchronized media, except if the synchronized media is an alternative to text and is clearly labeled as such . (Level A)

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 synchronized media 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 synchronized media.

• An instruction manual containing a description of a part and its necessary orientation is accompanied by a synchronized media clip showing the part in its correct orientation. No captions are provided for the synchronized media clip.

Techniques and Failures for Success Criterion 1.2.1 [Captions (Prerecorded)]

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

Key Terms

captions

text presented and synchronized with synchronized media to provide not only the speech, but also non-speech information conveyed through sound, including meaningful sound effects and identification of speakers

Note 1: In some countries, the term "subtitle" is used to refer to dialogue only and "captions" is used as the term for dialogue plus sounds and speaker identification. In other countries, subtitle (or its translation) is used to refer to both.

Note 2: Audio descriptions can be, but do not need to be, captioned since they are descriptions of information that is already presented visually.

media alternative to text

media that presents no more information than is already presented in text (directly or via text alternatives)

Note: A media alternative to text is provided for those who benefit from alternate representations of text. Media alternatives to text may be audio-only, video-only (including sign-language video), or audio-video.

synchronized media

audio or video synchronized with another format for presenting information and/or with time-based interactive components

---

Audio Description or Full Text Alternative:
Understanding SC 1.2.2

1.2.2 Audio Description or Full Text Alternative: Audio description of video, or a full text alternative for synchronized media including any interaction , is provided for prerecorded synchronized media. (Level A)

Note: For 1.2.2, 1.2.4, and 1.2.7, if all of the information in the video track is already provided in the audio track, no audio description is necessary.

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 synchronized media 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 synchronized media that all employees, including those who cannot see the demonstrations, can use to better understand what is being presented.

Techniques and Failures for Success Criterion 1.2.2 [Audio Description or Full Text Alternative]

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

Key Terms

audio description

narration added to the soundtrack to describe important visual details that cannot be understood from the main soundtrack alone

Note 1: Audio description of video provides information about actions, characters, scene changes, on-screen text, and other visual content.

Note 2: In standard audio description, narration is added during existing pauses in dialogue. (See also extended audio description.)

Note 3: Also called "video description" and "descriptive narration."

full text alternative for synchronized media including any interaction

document including correctly sequenced text descriptions of all visual settings, actions, speakers, and non-speech sounds, and transcript of all dialogue combined with a means of achieving any outcomes that are achieved using interaction (if any) during the synchronized media

Note: A screenplay used to create the synchronized media content would meet this definition only if it was corrected to accurately represent the final synchronized media after editing.

synchronized media

audio or video synchronized with another format for presenting information and/or with time-based interactive components

---

Captions (Live):
Understanding SC 1.2.3

1.2.3 Captions (Live): Captions are provided for live synchronized media. (Level AA)

Note: If synchronized media is completely computer generated, it is not live and is subject to the requirements for prerecorded synchronized media in WCAG 2.0.

Examples of Success Criterion 1.2.3

• A Web cast

  A news organization provides a live, captioned Web cast.

Techniques and Failures for Success Criterion 1.2.3 [Captions (Live)]

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

Key Terms

captions

text presented and synchronized with synchronized media to provide not only the speech, but also non-speech information conveyed through sound, including meaningful sound effects and identification of speakers

Note 1: In some countries, the term "subtitle" is used to refer to dialogue only and "captions" is used as the term for dialogue plus sounds and speaker identification. In other countries, subtitle (or its translation) is used to refer to both.

Note 2: Audio descriptions can be, but do not need to be, captioned since they are descriptions of information that is already presented visually.

synchronized media

audio or video synchronized with another format for presenting information and/or with time-based interactive components

---

Audio Description:
Understanding SC 1.2.4

1.2.4 Audio Description: Audio description of video is provided for prerecorded synchronized media. (Level AA)

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.)

Techniques and Failures for Success Criterion 1.2.4 [Audio Description]

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

Key Terms

audio description

narration added to the soundtrack to describe important visual details that cannot be understood from the main soundtrack alone

Note 1: Audio description of video provides information about actions, characters, scene changes, on-screen text, and other visual content.

Note 2: In standard audio description, narration is added during existing pauses in dialogue. (See also extended audio description.)

Note 3: Also called "video description" and "descriptive narration."

synchronized media

audio or video synchronized with another format for presenting information and/or with time-based interactive components

---

Sign Language:
Understanding SC 1.2.5

1.2.5 Sign Language: Sign language interpretation is provided for prerecorded synchronized media. (Level AAA)

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 synchronized media 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 synchronized media version.

Techniques and Failures for Success Criterion 1.2.5 [Sign Language]

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

Key Terms

sign language interpretation

translation of one language, generally a spoken language, into a sign language

Note: True sign languages are independent languages that are unrelated to the spoken language(s) of the same country or region.

synchronized media

audio or video synchronized with another format for presenting information and/or with time-based interactive components

---

Audio Description (Extended):
Understanding SC 1.2.6

1.2.6 Audio Description (Extended): Extended audio description of video is provided for prerecorded synchronized media. (Level AAA)

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.

Techniques and Failures for Success Criterion 1.2.6 [Audio Description (Extended)]

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

Key Terms

extended audio description

audio description that is added to an audiovisual presentation by pausing the video so that there is time to add additional description

Note: This technique is only used when the sense of the video would be lost without the additional audio description.

synchronized media

audio or video synchronized with another format for presenting information and/or with time-based interactive components

---

Full Text Alternative:
Understanding SC 1.2.7

1.2.7 Full Text Alternative: A full text alternative for synchronized media including any interaction is provided for all prerecorded synchronized media, except if the synchronized media is an alternative to text and is clearly labeled as such . (Level AAA)

Examples of Success Criterion 1.2.7

• Example 1. full text alternative for synchronized media 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 synchronized media that all clients, including those who can neither see the demonstrations nor hear the explanations in the synchronized media, can use to better understand what is being presented.

Techniques and Failures for Success Criterion 1.2.7 [Full Text Alternative]

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

Key Terms

full text alternative for synchronized media including any interaction

document including correctly sequenced text descriptions of all visual settings, actions, speakers, and non-speech sounds, and transcript of all dialogue combined with a means of achieving any outcomes that are achieved using interaction (if any) during the synchronized media

Note: A screenplay used to create the synchronized media content would meet this definition only if it was corrected to accurately represent the final synchronized media after editing.

media alternative to text

media that presents no more information than is already presented in text (directly or via text alternatives)

Note: A media alternative to text is provided for those who benefit from alternate representations of text. Media alternatives to text may be audio-only, video-only (including sign-language video), or audio-video.

---

Adaptable:
Understanding Guideline 1.3

Guideline 1.3: Create content that can be presented in different ways (for example simpler layout2094 ) without losing information or structure

Info and Relationships:
Understanding SC 1.3.1

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

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.

• 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.

• 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.

Techniques and Failures for Success Criterion 1.3.1 [Info and Relationships]

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

Key Terms

assistive technology (as used in this document)

hardware and/or software that acts as a user agent, or along with a mainstream user agent, to provide functionality to meet the requirements of users with disabilities that go beyond those offered by mainstream user agents

Note 1: functionality provided by assistive technology includes alternative presentations (e.g., as synthesized speech or magnified content), alternative input methods (e.g., voice), additional navigation or orientation mechanisms, and content transformations (e.g., to make tables more accessible).

Note 2: Assistive technologies often communicate data and messages with mainstream user agents by using and monitoring APIs.

Note 3: The distinction between mainstream user agents and assistive technologies is not absolute. Many mainstream user agents provide some features to assist individuals with disabilities. The basic difference is that mainstream user agents target broad and diverse audiences that usually include people with and without disabilities. Assistive technologies target narrowly defined populations of users with specific disabilities. The assistance provided by an assistive technology is more specific and appropriate to the needs of its target users. The mainstream user agent may provide important functionality to assistive technologies like retrieving Web content from program objects or parsing markup into identifiable bundles.

Example: Examples of assistive technologies that are important in the context of this document include the following:

• screen magnifiers, and other visual reading assistants, which are used by people with visual, perceptual and physical print disabilities to change text font, size, spacing, color, synchronization with speech, etc. in order to improve the visual readability of rendered text and images;

• screen readers, which are used by people who are blind to read textual information through synthesized speech or braille;

• text-to-speech software, which is used by some people with cognitive, language, and learning disabilities to convert text into synthetic speech;

• voice recognition software, which may be used by people who have some physical disabilities;

• alternative keyboards, which are used by people with certain physical disabilities to simulate the keyboard (including alternate keyboards that use head pointers, single switches, sip/puff and other special input devices.);

• alternative pointing devices, which are used by people with certain physical disabilities to simulate mouse pointing and button activations.

presentation

rendering of the content in a form to be perceived by users

programmatically determined / programmatically determinable

determined by software from author-supplied data provided in a way that different user agents, including assistive technologies, can extract and present this information to users in different modalities

Example: Determined in a markup language from elements and attributes that are accessed directly by commonly available assistive technology.

Example: Determined from technology-specific data structures in a non-markup language and exposed to assistive technology via an accessibility API that is supported by commonly available assistive technology.

relationships

meaningful associations between distinct pieces of content

user agent

any software that retrieves and presents Web content for users

Example: Web browsers, media players, plug-ins, and other programs — including assistive technologies — that help in retrieving, rendering, and interacting with Web content.

---

Meaningful Sequence:
Understanding SC 1.3.2

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

Examples of Success Criterion 1.3.2

• 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.

Techniques and Failures for Success Criterion 1.3.2 [Meaningful Sequence]

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

Key Terms

programmatically determined / programmatically determinable

determined by software from author-supplied data provided in a way that different user agents, including assistive technologies, can extract and present this information to users in different modalities

Example: Determined in a markup language from elements and attributes that are accessed directly by commonly available assistive technology.

Example: Determined from technology-specific data structures in a non-markup language and exposed to assistive technology via an accessibility API that is supported by commonly available assistive technology.

---

Sensory Characteristics:
Understanding SC 1.3.3

1.3.3 Sensory Characteristics: Instructions provided for understanding and operating content do not rely solely on sensory characteristics of components such as shape, size, visual location, orientation or sound. (Level A)

Examples of Success Criterion 1.3.3

• 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.

• Example 2: An on-line multi-page survey

  An on-line 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.

Techniques and Failures for Success Criterion 1.3.3 [Sensory Characteristics]

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

---

Distinguishable:
Understanding Guideline 1.4

Guideline 1.4: Make it easier for users2204 to see and hear content including separating foreground from background

Use of Color:
Understanding SC 1.4.1

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

Note 1: This success criterion addresses color perception specifically. Other forms of perception are covered in Guideline 1.3.

Note 2: Programmatic access to color and other visual presentation coding is covered in Guideline 1.3.

Examples of Success Criterion 1.4.1

• 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 A.)

• 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.

Techniques and Failures for Success Criterion 1.4.1 [Use of Color]

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

---

Audio Control:
Understanding SC 1.4.2

1.4.2 Audio Control: If any audio on a Web page plays automatically for more than 3 seconds, either a mechanism is available to pause or stop the audio, or a mechanism is available to control audio volume which can be set to be a different level from the system volume level . (Level A)

Note: Since any content that does not meet this success criterion can interfere with a user's ability to use the whole page, all content on the Web page (whether it is used to meet other success criteria or not) must meet this success criterion. See Conformance Requirement 5: Non-Interference.

Examples of Success Criterion 1.4.2

• 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.

• A Flash splash page with sound that plays automatically includes a control at the top that allows users to turn the sound off.

Techniques and Failures for Success Criterion 1.4.2 [Audio Control]

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

Key Terms

mechanism

process or technique for achieving a result

Note 1: The mechanism may be explicitly provided in the content, or may be relied on to be provided by either the platform or by user agents, including assistive technologies.

Note 2: The mechanism must meet all success criteria for the conformance level claimed.

---

Contrast (Minimum):
Understanding SC 1.4.3

1.4.3 Contrast (Minimum): Text and images of text have a contrast ratio of at least 5:1, except for the following: (Level AA)

• Large Print: Large-scale text and large-scale images of text have a contrast ratio of at least 3:1;

• Incidental: Text or images of text that are part of an inactive user interface component, that are pure decoration, that are incidental text in an image, or that are not visible to anyone, have no minimum contrast requirement.

Note: Success Criteria 1.4.3 and 1.4.6 can be met via a contrast control available on or from the page.

Examples of Success Criterion 1.4.3

Techniques and Failures for Success Criterion 1.4.3 [Contrast (Minimum)]

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

Key Terms

contrast ratio

(L1 + 0.05) / (L2 + 0.05), where

• L1 is the relative luminance of the lighter of the foreground or background colors, and

• L2 is the relative luminance of the darker of the foreground or background colors.

Note 1: Contrast ratios can range from 1 to 21 (commonly written 1:1 to 21:1).

Note 2: For dithered colors, use the average values of the colors that are dithered (average R, average G, and average B).

Note 3: Text can be evaluated with anti-aliasing turned off.

Note 4: Background color is the specified color of content over which the text is to be rendered in normal usage. If no background color is specified, then white is assumed.

Note 5: Background color is the specified color of content over which the text is to be rendered in normal usage. It is a failure if no background color is specified when a foreground color is specified, because the user's default background color is unknown and cannot be evaluated for sufficient contrast. For the same reason, it is a failure if no foreground color is specified when a background color is specified.

incidental text in an image

text that is inconsequential to the meaning of the image

Example: In a photo of two men talking on a street corner, there is a sign on a store in the background.

larger scale (text)

with at least 18 point or 14 point bold or font size that would yield equivalent stroke width for Chinese, Japanese and Korean (CJK) fonts

Note 1: Fonts with extraordinarily thin strokes or unusual features and characteristics that reduce the familiarity of their letter forms are harder to read, especially at lower contrast levels.

Note 2: Font size is the size when the content is delivered. It does not include resizing that may be done by a user.

Note 3: The actual size of the character that a user sees in dependent both on the author-defined size and the users display or user-agent settings. This success criterion is based on common pixel sizes available today. Users who have low vision would be responsible for choosing appropriate settings.

text

sequence of characters that can be programmatically determined, where the sequence is expressing something in human language

---

Resize text:
Understanding SC 1.4.4

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

Examples of Success Criterion 1.4.4

• A user with vision impairments increases the text size on a web page in a browser from 1 em to 1.2 ems. While the user could not read the text at the smaller size, she can read the larger text. All the information on the page is still displayed when the larger font is used for the text.

• A Web page contains a control for changing the scale of the page. Selecting different settings changes the layout of the page to use the best design for that scale.

• A user uses a zoom function in his user agent to change the scale of the content. All the content scales uniformly, and the user agent provides scroll bars, if necessary.

Techniques and Failures for Success Criterion 1.4.4 [Resize text]

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

Key Terms

assistive technology (as used in this document)

hardware and/or software that acts as a user agent, or along with a mainstream user agent, to provide functionality to meet the requirements of users with disabilities that go beyond those offered by mainstream user agents

Note 1: functionality provided by assistive technology includes alternative presentations (e.g., as synthesized speech or magnified content), alternative input methods (e.g., voice), additional navigation or orientation mechanisms, and content transformations (e.g., to make tables more accessible).

Note 2: Assistive technologies often communicate data and messages with mainstream user agents by using and monitoring APIs.

Note 3: The distinction between mainstream user agents and assistive technologies is not absolute. Many mainstream user agents provide some features to assist individuals with disabilities. The basic difference is that mainstream user agents target broad and diverse audiences that usually include people with and without disabilities. Assistive technologies target narrowly defined populations of users with specific disabilities. The assistance provided by an assistive technology is more specific and appropriate to the needs of its target users. The mainstream user agent may provide important functionality to assistive technologies like retrieving Web content from program objects or parsing markup into identifiable bundles.

Example: Examples of assistive technologies that are important in the context of this document include the following:

• screen magnifiers, and other visual reading assistants, which are used by people with visual, perceptual and physical print disabilities to change text font, size, spacing, color, synchronization with speech, etc. in order to improve the visual readability of rendered text and images;

• screen readers, which are used by people who are blind to read textual information through synthesized speech or braille;

• text-to-speech software, which is used by some people with cognitive, language, and learning disabilities to convert text into synthetic speech;

• voice recognition software, which may be used by people who have some physical disabilities;

• alternative keyboards, which are used by people with certain physical disabilities to simulate the keyboard (including alternate keyboards that use head pointers, single switches, sip/puff and other special input devices.);

• alternative pointing devices, which are used by people with certain physical disabilities to simulate mouse pointing and button activations.

text

sequence of characters that can be programmatically determined, where the sequence is expressing something in human language

---

Images of Text (Limited):
Understanding SC 1.4.5

1.4.5 Images of Text (Limited): When the accessibility supported technologies being used can achieve the visual presentation, text is used to convey information rather than images of text except for the following: (Level AA)

• Customizable: The image of text can be visuallycustomized to the user's requirements;

• Essential: A particular presentation of text is essential to the information being conveyed.

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

Examples of Success Criterion 1.4.5

• Styled Headings

  Rather than using bitmap images to present headings in a specific font and size, an author uses CSS to achieve the same result.

• Dynamically Generated Images

  A Web page uses server-side scripting to present text as an an image. The page includes controls that allow the user to adjust the font size and foreground and background colors of the generated image.

• A quote

  A web page contains a quote. The quote itself is presented as italicized text, indented from the left margin. The name of the person to whom the quote is attributed is below the quote with 1.5x the line space and further indented from the left margin. CSS is used to position the text; set the spacing between lines; as well as display the text's font family, size, color and decoration.

• Navigation items

  A web page contains a menu of navigation links that have both an icon and text to describe their target. CSS is used to display the text's font family, size and foreground and background colors; as well as the spacing between the navigation links.

• A logo containing text

  A web site contains the organisation's logo in the top left corner of each web page. The logo contains logotype (text as part, or all, of the logo). The visual presentation of the text is essential to the identity of the logo and is included as a gif image which does not allow the text characteristics to be changed. The image has a text alternative.

• Representation of a font family

  A web page contains information about a particular font family. Substituting the font family with another font would defeat the purpose of the representation. The representation is included as a jpeg image which does not allow the text characteristics to be changed. The image has a text alternative.

• A representation of a letter

  A web page contains a representation of an original letter. The depiction of the letter in its original format is essential to information being conveyed about the time period in which it was written. The letter is included as a gif image which does not allow the text characteristics to be changed. The image has a text alternative.

• Symbolic text characters

  A form allows users to enter blocks of text. The form provides a number of buttons, including functions to style the text and check spelling. Some of the buttons use text characters that do not form a sequence that expresses something in human language. For example "B" to increase font weight, "I" to italicize the text and "ABC" to check the spelling. The symbolic text characters are included as gif images which do not allow the text characteristics to be changed. The buttons have text alternatives.

Techniques and Failures for Success Criterion 1.4.5 [Images of Text (Limited)]

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

---

Contrast (Enhanced):
Understanding SC 1.4.6

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

• Large Print: Large-scale text and large-scale images of text have a contrast ratio of at least 5:1;

• Incidental: Text or images of text that are part of an inactive user interface component, that are pure decoration, that are incidental text in an image, or that are not visible to anyone, have no minimum contrast requirement.

Note: Success Criteria 1.4.3 and 1.4.6 can be met via a contrast control available on or from the page.

Examples of Success Criterion 1.4.6

Techniques and Failures for Success Criterion 1.4.6 [Contrast (Enhanced)]

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

Key Terms

contrast ratio

(L1 + 0.05) / (L2 + 0.05), where

• L1 is the relative luminance of the lighter of the foreground or background colors, and

• L2 is the relative luminance of the darker of the foreground or background colors.

Note 1: Contrast ratios can range from 1 to 21 (commonly written 1:1 to 21:1).

Note 2: For dithered colors, use the average values of the colors that are dithered (average R, average G, and average B).

Note 3: Text can be evaluated with anti-aliasing turned off.

Note 4: Background color is the specified color of content over which the text is to be rendered in normal usage. If no background color is specified, then white is assumed.

Note 5: Background color is the specified color of content over which the text is to be rendered in normal usage. It is a failure if no background color is specified when a foreground color is specified, because the user's default background color is unknown and cannot be evaluated for sufficient contrast. For the same reason, it is a failure if no foreground color is specified when a background color is specified.

incidental text in an image

text that is inconsequential to the meaning of the image

Example: In a photo of two men talking on a street corner, there is a sign on a store in the background.

larger scale (text)

with at least 18 point or 14 point bold or font size that would yield equivalent stroke width for Chinese, Japanese and Korean (CJK) fonts

Note 1: Fonts with extraordinarily thin strokes or unusual features and characteristics that reduce the familiarity of their letter forms are harder to read, especially at lower contrast levels.

Note 2: Font size is the size when the content is delivered. It does not include resizing that may be done by a user.

Note 3: The actual size of the character that a user sees in dependent both on the author-defined size and the users display or user-agent settings. This success criterion is based on common pixel sizes available today. Users who have low vision would be responsible for choosing appropriate settings.

text

sequence of characters that can be programmatically determined, where the sequence is expressing something in human language

---

Low or No Background Audio:
Understanding SC 1.4.7

1.4.7 Low or No Background Audio: Audio content that is not an audio CAPTCHA and that contains speech in the foreground does not contain background sounds, background sounds can be turned off, or background sounds are at least 20 decibels lower than the foreground speech content, with the exception of occasional sound effects. (Level AAA)

Note: Background sound that meets this requirement will be approximately one quarter as loud as the foreground speech content.

Examples of Success Criterion 1.4.7

Techniques and Failures for Success Criterion 1.4.7 [Low or No Background Audio]

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

---

Visual Presentation:
Understanding SC 1.4.8

1.4.8 Visual Presentation: For the visual presentation of blocks of text, a mechanism is available to achieve the following: (Level AAA)

• foreground and background colors can be selected by the user

• width is no more than 80 characters

• text is not aligned on both the left and the right

• line spacing is at least space-and-a-half within paragraphs, and paragraph spacing is larger than line spacing

• text is resized without assistive technology up to 200 percent in a way that does not require the user to scroll horizontally to read a line of text

Examples of Success Criterion 1.4.8

None currently documented

Techniques and Failures for Success Criterion 1.4.8 [Visual Presentation]

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

Key Terms

blocks of text

more than one sentence of text

---

Images of Text (Essential):
Understanding SC 1.4.9

1.4.9 Images of Text (Essential): Images of text are only used for pure decoration or where a particular presentation of text is essential to the information being conveyed. (Level AAA)

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

Examples of Success Criterion 1.4.9

• A quote

  A web page contains a quote. The quote itself is presented as italicized text, indented from the left margin. The name of the person to whom the quote is attributed is below the quote with 1.5x the line space and further indented from the left margin. CSS is used to position the text; set the spacing between lines; as well as display the text's font family, size, color and decoration.

• Navigation items

  A web page contains a menu of navigation links that have both an icon and text to describe their target. CSS is used to display the text's font family, size and foreground and background colors; as well as the spacing between the navigation links.

• A logo containing text

  A web site contains the organisation's logo in the top left corner of each web page. The logo contains logotype (text as part, or all, of the logo). The visual presentation of the text is essential to the identity of the logo and is included as a gif image which does not allow the text characteristics to be changed. The image has a text alternative.

• Representation of a font family

  A web page contains information about a particular font family. Substituting the font family with another font would defeat the purpose of the representation. The representation is included as a jpeg image which does not allow the text characteristics to be changed. The image has a text alternative.

• A representation of a letter

  A web page contains a representation of an original letter. The depiction of the letter in its original format is essential to information being conveyed about the time period in which it was written. The letter is included as a gif image which does not allow the text characteristics to be changed. The image has a text alternative.

• Symbolic text characters

  A form allows users to enter blocks of text. The form provides a number of buttons, including functions to style the text and check spelling. Some of the buttons use text characters that do not form a sequence that expresses something in human language. For example "B" to increase font weight, "I" to italicize the text and "ABC" to check the spelling. The symbolic text characters are included as gif images which do not allow the text characteristics to be changed. The buttons have text alternatives.

Techniques and Failures for Success Criterion 1.4.9 [Images of Text (Essential)]

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

Key Terms

pure decoration

serving only an aesthetic purpose, providing no information, and having no functionality

Note: Text is only purely decorative if the words can be rearranged or substituted without changing their purpose.

Example: The cover page of a dictionary has random words in very light text in the background.

text

sequence of characters that can be programmatically determined, where the sequence is expressing something in human language

---

Keyboard Accessible:
Understanding Guideline 2.1

Guideline 2.1: Make all functionality available from a keyboard

Keyboard:
Understanding SC 2.1.1

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

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

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

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.

Techniques and Failures for Success Criterion 2.1.1 [Keyboard]

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

Key Terms

functionality

processes and outcomes achievable through user action

keyboard interface

interface used by software to obtain keystroke input

Note 1: Allows users to provide keystroke input to programs even if the native technology does not contain a keyboard.

Example: A touch screen PDA has a keyboard interface built into its operating system as well as a connector for external keyboards. Applications on the PDA can use the interface to obtain keyboard input either from an external keyboard or from other applications that provide simulated keyboard output, such as handwriting interpreters or speech-to-text applications with "keyboard emulation" functionality.

Note 2: Operation of the application (or parts of the application) through a keyboard-operated mouse emulator, such as MouseKeys, does not qualify as operation through a keyboard interface because operation of the program is through its pointing device interface, not through its keyboard interface.

---

No Keyboard Trap:
Understanding SC 2.1.2

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

Note: Since any content that does not meet this success criterion can interfere with a user's ability to use the whole page, all content on the Web page (whether it is used to meet other success criteria or not) must meet this success criterion. See Conformance Requirement 5: Non-Interference.

Examples of Success Criterion 2.1.2

• A calendar widget

  A calendar widget allows users to add, remove or update items in their calendar using the keyboard. The controls in the widget are part of the tab order within the Web page, allowing users to tab through the controls in the widget as well as to any links or controls that follow.

• A puzzle applet

  Once a user tabs into an applet, further tabs and other keystrokes are handled by the applet. Instructions describing the keystroke used to exit the applet are provided prior to the applet as well as within the applet itself.

Techniques and Failures for Success Criterion 2.1.2 [No Keyboard Trap]

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

Key Terms

keyboard interface

interface used by software to obtain keystroke input

Note 1: Allows users to provide keystroke input to programs even if the native technology does not contain a keyboard.

Example: A touch screen PDA has a keyboard interface built into its operating system as well as a connector for external keyboards. Applications on the PDA can use the interface to obtain keyboard input either from an external keyboard or from other applications that provide simulated keyboard output, such as handwriting interpreters or speech-to-text applications with "keyboard emulation" functionality.

Note 2: Operation of the application (or parts of the application) through a keyboard-operated mouse emulator, such as MouseKeys, does not qualify as operation through a keyboard interface because operation of the program is through its pointing device interface, not through its keyboard interface.

---

Keyboard (No Exception):
Understanding SC 2.1.3

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

Techniques and Failures for Success Criterion 2.1.3 [Keyboard (No Exception)]

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

Key Terms

functionality

processes and outcomes achievable through user action

keyboard interface

interface used by software to obtain keystroke input

Note 1: Allows users to provide keystroke input to programs even if the native technology does not contain a keyboard.

Example: A touch screen PDA has a keyboard interface built into its operating system as well as a connector for external keyboards. Applications on the PDA can use the interface to obtain keyboard input either from an external keyboard or from other applications that provide simulated keyboard output, such as handwriting interpreters or speech-to-text applications with "keyboard emulation" functionality.

Note 2: Operation of the application (or parts of the application) through a keyboard-operated mouse emulator, such as MouseKeys, does not qualify as operation through a keyboard interface because operation of the program is through its pointing device interface, not through its keyboard interface.

---

Enough Time:
Understanding Guideline 2.2

Guideline 2.2: Provide users with disabilities enough time to read and use content

Timing Adjustable:
Understanding SC 2.2.1

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

• Turn off: the user is allowed to turn off the time limit before encountering it; or

• Adjust: the user is allowed to adjust the time limit before encountering it over a wide range that is at least ten times the length of the default setting; or

• Extend: the user is warned before time expires and given at least 20 seconds to extend the time limit with a simple action (for example, "press the space bar "), and the user is allowed to extend the time limit at least ten times; or

• Real-time Exception: the time limit is a required part of a real-time event (for example, an auction), and no alternative to the time limit is possible; or

• Essential Exception: the time limit cannot be extended without invalidating the activity; or

• 20 Hour Exception: the time limit is longer than 20 hours.

Note: This success criterion acts to ensure that changes in content or context as a result of a time limit will not occur unexpectedly, preventing users from completing tasks. While exceptions to success criterion 2.2.1 where timing is essential exist, guideline 2.2 in general limits changes in content for no reason. This success criterion should be considered in conjunction with Success Criterion 3.2.1 which puts limits on changes of content or context as a result of user action.

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 ten times the default. The control can be operated with either a mouse or a keyboard.

• 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.

• An on-line 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.

• 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.

Techniques and Failures for Success Criterion 2.2.1 [Timing Adjustable]

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

Key Terms

activity where moving, blinking, scrolling, or auto-updating is essential

activity where moving, blinking, scrolling, or auto-updating is central to the design of the activity and removal would fundamentally change the functionality of the content

---

Pausing:
Understanding SC 2.2.2

2.2.2 Pausing: Moving, blinking, scrolling, or auto-updating information on a Web page that lasts for more than three seconds can be paused by the user unless the movement, blinking, scrolling, or auto-updating is part of an activity where the changes are essential. Moving or blinking content that is pure decoration can be stopped or hidden by the user. (Level AA)

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

Note 2: Since any content that does not meet this success criterion can interfere with a user's ability to use the whole page, all content on the Web page (whether it is used to meet other success criteria or not) must meet this success criterion. See Conformance Requirement 5: Non-Interference.

Note 3: Content that is updated from a process, real-time or remote stream is not required to preserve or present information that is generated or received between the initiation of the pause and resuming presentation, as this may not be technically possible, and in many situations could be misleading to do so.

Examples of Success Criterion 2.2.2

• 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.

• 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.

• 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.

Techniques and Failures for Success Criterion 2.2.2 [Pausing]

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

Key Terms

activity where moving, blinking, scrolling, or auto-updating is essential

activity where moving, blinking, scrolling, or auto-updating is central to the design of the activity and removal would fundamentally change the functionality of the content

blink

switch back and forth between two visual states in a way that is meant to draw attention

Note: See also flash (It is possible for something to be large enough and blink brightly enough at the right frequency to be also classified as a flash).

paused

stopped by user request and not resumed until requested by user

Web page

a non-embedded resource obtained from a single URI using HTTP plus any other resources that are used in the rendering or intended to be rendered together with it by a user agent

Note 1: Although any "other resources" would be rendered together with the primary resource, they would not necessarily be rendered simultaneously with each other.

Note 2: For the purposes of conformance with these guidelines, a resource must be "non-embedded" within the scope of conformance to be considered a Web page.

Example 1: A Web resource including all embedded images and media.

Example 2: A Web mail program built using Asynchronous JavaScript and XML (AJAX). The program lives entirely at http://example.com/mail, but includes an inbox, a contacts area and a calendar. Links or buttons are provided that cause the inbox, contacts, or calendar to display, but do not change the URL of the page as a whole.

Example 3: A customizable portal site, where users can choose content to display from a set of different content modules.

Example 4: When you enter "http://shopping.example.com/" in your browser, you enter a movie-like interactive shopping environment where you visually move about a store dragging products off of the shelves around you and into a visual shopping cart in front of you. Clicking on a product causes it to be demonstrated with a specification sheet floating alongside.

---

No Timing:
Understanding SC 2.2.3

2.2.3 No Timing: Timing is not an essential part of the event or activity presented by the content, except for non-interactive synchronized media and real-time events. (Level AAA)

Examples of Success Criterion 2.2.3

• 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.

Techniques and Failures for Success Criterion 2.2.3 [No Timing]

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

Key Terms

real-time event

event that a) occurs at the same time as the viewing and b) is not completely generated by the content

Example 1: A Webcast of a live performance (occurs at the same time as the viewing and is not prerecorded).

Example 2: An on-line auction with people bidding (occurs at the same time as the viewing).

Example 3: Live humans interacting in a fantasy world using avatars (is not completely generated by the content and occurs at the same time as the viewing).

synchronized media

audio or video synchronized with another format for presenting information and/or with time-based interactive components

---

Interruptions:
Understanding SC 2.2.4

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

Examples of Success Criterion 2.2.4

• 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.

Techniques and Failures for Success Criterion 2.2.4 [Interruptions]

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

Key Terms

emergency

a sudden, unexpected situation or occurrence that requires immediate action to preserve health, safety, or property

---

Re-authenticating:
Understanding SC 2.2.5

2.2.5 Re-authenticating: When an authenticated session expires, the user can continue the activity without loss of data after re-authenticating. (Level AAA)

Examples of Success Criterion 2.2.5

• 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 while 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.

Techniques and Failures for Success Criterion 2.2.5 [Re-authenticating]

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

---

Seizures:
Understanding Guideline 2.3

Guideline 2.3: Do not design content in a way that is known to cause seizures 2312

Three Flashes or Below Threshold:
Understanding SC 2.3.1

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

Note: Since any content that does not meet this success criterion can interfere with a user's ability to use the whole page, all content on the Web page (whether it is used to meet other success criteria or not) must meet this success criterion. See Conformance Requirement 5: Non-Interference.

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.

• 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.

Techniques and Failures for Success Criterion 2.3.1 [Three Flashes or Below Threshold]

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

Key Terms

general flash and red flash thresholds

a sequence of flashes or rapidly changing image sequences where all three of the following are true:

1. there are more than three General Flashes and / or more than three Red Flashes within any one-second period; and

2. the flashing is below 50 Hz; and

3. the combined area of flashes occurring concurrently occupies more than a total of .006 steradians within any 10 degree visual field on the screen (25% of any 10 degree visual field on the screen) at typical viewing distance, where:

   • A General Flash is defined as a pair of opposing changes in relative luminance of 10% or more and the relative luminance of the darker image is below 0.80; where an "a pair of opposing changes" is an increase followed by a decrease, or a decrease followed by an increase, and

   • A Red Flash is defined as any pair of opposing transitions involving a saturated red.

Exception: Flashing that is a fine, balanced, pattern such as white noise or an alternating checkerboard pattern with "squares" smaller than 0.1 degree on a side does not violate the thresholds.

Note 1: For general software or Web content, using a 341 x 256 pixel rectangle anywhere on the displayed screen area when the content is viewed at 1024 x 768 pixels will provide a good estimate of a 10 degree visual field for standard screen sizes and viewing distances (e.g. 15-17 inch screen at 22-26 inches). (Higher resolutions yield smaller and safer images so it is lower resolutions that are used to define the thresholds.)

Note 2: The current working definition in the field for "pair of opposing transitions involving a saturated red" is where, for either or both states involved in each transition, R/(R+ G + B) >= 0.8, and the change in the value of (R-G-B)x320 is > 20 (negative values of (R-G-B)x320 are set to zero) for both transitions. R, G, B values range from 0-1 as specified in “relative luminance” definition. (Harding and Binnie 2002)

Note 3: Tools are available that will carry out analysis from video screen capture.

Note 4: No tool is necessary to evaluate for this condition if flashing is less than or equal to 3 flashes in any one second or greater than 50 Hz. Content automatically passes (see #1 and #2 above).

Note 5: 50 Hz is used to coincide with the AC line frequency in Europe and other countries. However almost half of the population is susceptible to 50 Hz flashing whereas only 15 % are susceptible to 60 Hz. 75 Hz or higher is recommended where possible.

Web page

a non-embedded resource obtained from a single URI using HTTP plus any other resources that are used in the rendering or intended to be rendered together with it by a user agent

Note 1: Although any "other resources" would be rendered together with the primary resource, they would not necessarily be rendered simultaneously with each other.

Note 2: For the purposes of conformance with these guidelines, a resource must be "non-embedded" within the scope of conformance to be considered a Web page.

Example 1: A Web resource including all embedded images and media.

Example 2: A Web mail program built using Asynchronous JavaScript and XML (AJAX). The program lives entirely at http://example.com/mail, but includes an inbox, a contacts area and a calendar. Links or buttons are provided that cause the inbox, contacts, or calendar to display, but do not change the URL of the page as a whole.

Example 3: A customizable portal site, where users can choose content to display from a set of different content modules.

Example 4: When you enter "http://shopping.example.com/" in your browser, you enter a movie-like interactive shopping environment where you visually move about a store dragging products off of the shelves around you and into a visual shopping cart in front of you. Clicking on a product causes it to be demonstrated with a specification sheet floating alongside.

---

Three Flashes:
Understanding SC 2.3.2

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

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.

Techniques and Failures for Success Criterion 2.3.2 [Three Flashes]

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

Key Terms

Web page

a non-embedded resource obtained from a single URI using HTTP plus any other resources that are used in the rendering or intended to be rendered together with it by a user agent

Note 1: Although any "other resources" would be rendered together with the primary resource, they would not necessarily be rendered simultaneously with each other.

Note 2: For the purposes of conformance with these guidelines, a resource must be "non-embedded" within the scope of conformance to be considered a Web page.

Example 1: A Web resource including all embedded images and media.

Example 2: A Web mail program built using Asynchronous JavaScript and XML (AJAX). The program lives entirely at http://example.com/mail, but includes an inbox, a contacts area and a calendar. Links or buttons are provided that cause the inbox, contacts, or calendar to display, but do not change the URL of the page as a whole.

Example 3: A customizable portal site, where users can choose content to display from a set of different content modules.

Example 4: When you enter "http://shopping.example.com/" in your browser, you enter a movie-like interactive shopping environment where you visually move about a store dragging products off of the shelves around you and into a visual shopping cart in front of you. Clicking on a product causes it to be demonstrated with a specification sheet floating alongside.

---

Navigable:
Understanding Guideline 2.4

Guideline 2.4: Provide ways to help users with disabilities navigate, find content and determine where they are

Bypass Blocks:
Understanding SC 2.4.1

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

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.

Techniques and Failures for Success Criterion 2.4.1 [Bypass Blocks]

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

Key Terms

Web page

a non-embedded resource obtained from a single URI using HTTP plus any other resources that are used in the rendering or intended to be rendered together with it by a user agent

Note 1: Although any "other resources" would be rendered together with the primary resource, they would not necessarily be rendered simultaneously with each other.

Note 2: For the purposes of conformance with these guidelines, a resource must be "non-embedded" within the scope of conformance to be considered a Web page.

Example 1: A Web resource including all embedded images and media.

Example 2: A Web mail program built using Asynchronous JavaScript and XML (AJAX). The program lives entirely at http://example.com/mail, but includes an inbox, a contacts area and a calendar. Links or buttons are provided that cause the inbox, contacts, or calendar to display, but do not change the URL of the page as a whole.

Example 3: A customizable portal site, where users can choose content to display from a set of different content modules.

Example 4: When you enter "http://shopping.example.com/" in your browser, you enter a movie-like interactive shopping environment where you visually move about a store dragging products off of the shelves around you and into a visual shopping cart in front of you. Clicking on a product causes it to be demonstrated with a specification sheet floating alongside.

---

Page Titled:
Understanding SC 2.4.2

2.4.2 Page Titled: Web pages have descriptive titles. (Level A)

Examples of Success Criterion 2.4.2

• An HTML Web page

  The descriptive title of an HTML web page is marked up with the <title> element so that it will be displayed in the title bar of the user agent.

• 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."

• 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".

Techniques and Failures for Success Criterion 2.4.2 [Page Titled]

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

Key Terms

Web page

a non-embedded resource obtained from a single URI using HTTP plus any other resources that are used in the rendering or intended to be rendered together with it by a user agent

Note 1: Although any "other resources" would be rendered together with the primary resource, they would not necessarily be rendered simultaneously with each other.

Note 2: For the purposes of conformance with these guidelines, a resource must be "non-embedded" within the scope of conformance to be considered a Web page.

Example 1: A Web resource including all embedded images and media.

Example 2: A Web mail program built using Asynchronous JavaScript and XML (AJAX). The program lives entirely at http://example.com/mail, but includes an inbox, a contacts area and a calendar. Links or buttons are provided that cause the inbox, contacts, or calendar to display, but do not change the URL of the page as a whole.

Example 3: A customizable portal site, where users can choose content to display from a set of different content modules.

Example 4: When you enter "http://shopping.example.com/" in your browser, you enter a movie-like interactive shopping environment where you visually move about a store dragging products off of the shelves around you and into a visual shopping cart in front of you. Clicking on a product causes it to be demonstrated with a specification sheet floating alongside.

---

Focus Order (Relationships):
Understanding SC 2.4.3

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

Examples of Success Criterion 2.4.3

1. 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").

2. 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.

3. A Web page implements modeless dialogs via scripting. When the trigger button is activated, a dialog opens. The interactive elements in the dialog are inserted in the focus order immediately after the button. When the dialog is open, the focus order goes from the button to the elements of the dialog, then to the interactive element following the button. When the dialog is closed, the focus order goes from the button to the following element.

4. A Web page implements modal dialogs via scripting. When the trigger button is activated, a dialog opens and focus is set to the first interactive element in the dialog. As long as the dialog is open, focus is limited to the elements of the dialog. When the dialog is dismissed, focus returns to the button or the element following the button.

5. An HTML web page is created with the left hand navigation occurring in the HTML after the main body content, and styled with CSS to appear on the left hand side of the page. This is done to allow focus to move to the main body content first without requiring tabIndex attributes or JavaScript.

   Note: While this example passes the SC, it is not necessarily true that all CSS positioning would. More complex positioning examples may or may not preserve meaning and operability

6. The following example fails to meet the success criterion:

   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, so that focus moves from the name field to a checkbox, then to the street address, then to another checkbox.

Techniques and Failures for Success Criterion 2.4.3 [Focus Order (Relationships)]

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

Key Terms

navigated sequentially

navigated in the order defined for advancing focus (from one element to the next) using the keyboard

Web page

a non-embedded resource obtained from a single URI using HTTP plus any other resources that are used in the rendering or intended to be rendered together with it by a user agent

Note 1: Although any "other resources" would be rendered together with the primary resource, they would not necessarily be rendered simultaneously with each other.

Note 2: For the purposes of conformance with these guidelines, a resource must be "non-embedded" within the scope of conformance to be considered a Web page.

Example 1: A Web resource including all embedded images and media.

Example 2: A Web mail program built using Asynchronous JavaScript and XML (AJAX). The program lives entirely at http://example.com/mail, but includes an inbox, a contacts area and a calendar. Links or buttons are provided that cause the inbox, contacts, or calendar to display, but do not change the URL of the page as a whole.

Example 3: A customizable portal site, where users can choose content to display from a set of different content modules.

Example 4: When you enter "http://shopping.example.com/" in your browser, you enter a movie-like interactive shopping environment where you visually move about a store dragging products off of the shelves around you and into a visual shopping cart in front of you. Clicking on a product causes it to be demonstrated with a specification sheet floating alongside.

---

Link Purpose (In Context):
Understanding SC 2.4.4

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

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.

Techniques and Failures for Success Criterion 2.4.4 [Link Purpose (In Context)]

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

Key Terms

ambiguous to users in general

the purpose cannot be determined from the link and all information of the Web page presented to the user simultaneously with the link (i.e. readers without disabilities would not know what a link would do until they activated it)

Example: The word guava in the following sentence "One of the notable exports is guava" is a link. The link could lead to a definition of guava, a chart listing the quantity of guava exported or a photograph of people harvesting guava. Until the link is activated, all readers are unsure and the person with a disability is not at any disadvantage.

link purpose

nature of the result obtained by activating a hyperlink

Programmatically determiend (programmatically determinable) link context

additional information that can be programmatically determined from relationships with a link, combined with the link text, and presented to users in different modalities

Example: In HTML, information that is programmatically determinable from a link in English includes text that is in the same paragraph, list, or table cell as the link or in a table header cell that is associated with the table cell that contains the link.

Note: Since screen readers interpret punctuation, they can also provide the context from the current sentence, when the focus is on a link in that sentence.

---

Multiple Ways:
Understanding SC 2.4.5

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

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.

Techniques and Failures for Success Criterion 2.4.5 [Multiple Ways]

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

Key Terms

process

series of user actions where each action is required in order to complete an activity

Example 1: Successful use of a series of Web pages on a shopping site requires users to view alternative products, prices and offers, select products, submit an order, provide shipping information and provide payment information.

Example 2: An account registration page requires successful completion of a Turing test before the registration form can be accessed.

set of Web pages

collection of Web pages that share a common purpose and that are created by the same author, group or organization

Note: Different language versions would be considered different sets of Web pages .

Web page

a non-embedded resource obtained from a single URI using HTTP plus any other resources that are used in the rendering or intended to be rendered together with it by a user agent

Note 1: Although any "other resources" would be rendered together with the primary resource, they would not necessarily be rendered simultaneously with each other.

Note 2: For the purposes of conformance with these guidelines, a resource must be "non-embedded" within the scope of conformance to be considered a Web page.

Example 1: A Web resource including all embedded images and media.

Example 2: A Web mail program built using Asynchronous JavaScript and XML (AJAX). The program lives entirely at http://example.com/mail, but includes an inbox, a contacts area and a calendar. Links or buttons are provided that cause the inbox, contacts, or calendar to display, but do not change the URL of the page as a whole.

Example 3: A customizable portal site, where users can choose content to display from a set of different content modules.

Example 4: When you enter "http://shopping.example.com/" in your browser, you enter a movie-like interactive shopping environment where you visually move about a store dragging products off of the shelves around you and into a visual shopping cart in front of you. Clicking on a product causes it to be demonstrated with a specification sheet floating alongside.

---

Labels Descriptive:
Understanding SC 2.4.6

2.4.6 Labels Descriptive: Labels and headings are descriptive. (Level AA)

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.

Techniques and Failures for Success Criterion 2.4.6 [Labels Descriptive]

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

Key Terms

label

text or other component with a text alternative that is presented to a user to identify a component within Web content

Note 1: A label is presented to all users whereas the name may be hidden and only exposed by assistive technology. In many (but not all) cases the name and the label are the same.

Note 2: The term label is not limited to the label element in HTML.

---

Focus Visible:
Understanding SC 2.4.7

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

Examples of Success Criterion 2.4.7

• When text fields receive focus, a vertical bar is displayed in the field, indicating that the user can insert text, OR all of the text is highlighted, indicating that the user can type over the text.

• When a user interface control receives focus, a visible border is displayed around it.

Techniques and Failures for Success Criterion 2.4.7 [Focus Visible]

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

---

Location:
Understanding SC 2.4.8

2.4.8 Location: Information about the user's location within a set of Web pages is available. (Level AAA)

Examples of Success Criterion 2.4.8

• 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.

Techniques and Failures for Success Criterion 2.4.8 [Location]

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

Key Terms

set of Web pages

collection of Web pages that share a common purpose and that are created by the same author, group or organization

Note: Different language versions would be considered different sets of Web pages .

---

Link Purpose (Link Only):
Understanding SC 2.4.9

2.4.9 Link Purpose (Link Only): A mechanism is available to allow the purpose of each link to be identified from link text alone, except where the purpose of the link would be ambiguous to users in general. (Level AAA)

Examples of Success Criterion 2.4.9

• 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."

Techniques and Failures for Success Criterion 2.4.9 [Link Purpose (Link Only)]

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

---

Section Headings:
Understanding SC 2.4.10

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

Note: "Heading" is used in its general sense and includes titles and