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Copyright © 2007 W3C® (MIT, ERCIM, Keio), All Rights Reserved. W3C liability, trademark and document use rules apply.
This document, "Understanding WCAG 2.0," is an essential guide to understanding and using "Web Content Accessibility Guidelines 2.0" [WCAG20]. It is part of a series of documents that support WCAG 2.0.
WCAG 2.0 establishes a set of success criteria to define conformance to the WCAG 2.0 Guidelines. A success criterion is a testable statement that will be either true or false when applied to specific Web content. "Understanding WCAG 2.0" provides detailed information about each success criterion, including its intent; the key terms that are used in the success criterion; examples of Web content that meet the success criterion using various Web technologies (for instance, HTML, CSS, XML) and common examples of Web content that does not meet the success criterion. Finally, this document also explains how the success criteria in WCAG 2.0 help people with different types of disabilities.
This document is the internal working draft used by the WCAG WG and is updated continuously and without notice. This document has no formal standing within W3C. Please consult the group's home page and the W3C technical reports index for information about the latest publications by this group.
This draft includes revisions that have been made since the 27 April 2006 Working Draft was published. Please refer to the latest public version of WCAG 2.0 for information about the status of WCAG 2.0 as well as information about submitting comments to the working group.
Understanding WCAG 2.0 is an essential guide to understanding and using "Web Content Accessibility Guidelines 2.0" [WCAG20] Although the definition and requirements for WCAG 2.0 can all be found in the WCAG 2.0 document itself, the concepts and provisions may be new to some people. Understanding WCAG 2.0 provides an extended commentary on each guideline and each success criterion to help readers better understand the intent and how the guidelines and success criteria work together. It also provides examples of techniques or combinations of techniques that the Working Group has identified as being sufficient to meet each success criterion. Links are then provided to write-ups for each of the techniques.
Editorial Note: Where the committee has not yet been able to write up the description of a techniques, the techniques are listed with "(future link)" following their title.
This is not an introductory document. It is a detailed technical description of the guidelines and their success criteria. For an introduction to WCAG 2.0 and the complete set of documents associated with the guidelines, see Overview of Web Content Accessibility Guidelines (WCAG) 2.0 Documents. [LC-1016]
[end add]Understanding WCAG 2.0 is organized by guideline. There is an Understanding Guideline X.X section for each guideline. The intent and any advisory techniques that are related to the guideline but not specifically related to any of its success criteria are listed there as well.
The Understanding Guidelines X.X section is then followed by a How to Meet Success Criterion X.X.X section for each success criterion of that guideline. These How to Meet sections each contain:
The success criterion as it appears in WCAG 2.0
Key terms for this success criterion (taken from the WCAG 2.0 Glossary)
Intent of the success criterion
Techniques or combinations of techniques that are sufficient to meet the guidelines
Common failures of this success criterion
Additional advisory techniques that go beyond what is required to meet the success criterion but can be used to make some or all types of content more accessible. [begin add]Use of advisory techniques does not impact the level of conformance claimed.[end add]
Benefits (how the success criterion helps people with disabilities)
Examples
[begin add]Related Resources[end add]
Links are provided from each Guideline in WCAG 2.0 directly to each Understanding Guideline X.X in this document. Similarly, there is a link from each success criterion in WCAG 2.0 to the How to Meet Success Criterion X.X.X section in this document.
For information about individual techniques, follow the links throughout this document to the techniques of interest in the Techniques for WCAG 2.0 document.
The WCAG 2.0 Guidelines are organized around the following four principles. These principles are basic principle that apply to all Web users.
Perceivable - Information and user interface must be perceivable by the user
This means that users must be able to perceive the information being presented (it can't be invisible to all of their senses)
Operable - User interface components must be operable by the user
This means that users must be able to operate the interface (the interface cannot require interaction that the user can not perform)
Understandable - Information and operation of user interface must be understandable by the user
This means that users must be able to understand the information as well as the operation of the user interface (the content or operation cannot be beyond their understanding)
Robust - Content must be robust enough that it can be interpreted reliably by a wide variety of user agents, including assistive technologies
This means that users must be able to access the content as technologies advance (as technologies and user agents evolve, the content should remain accessible)
If any of these are not true, users with disabilities will not be able to use the Web.
Under each of the principles are guidelines and success criteria that help to address these principles for people with disabilities. There are many general usability guidelines that make content more usable by all people, including those with disabilities. However, in WCAG 2.0, we only include those guidelines that address problems particular to people with disabilities. This includes issues that block access or interfere with access to the Web more severely for people with disabilities.
[LC-1019]
The purpose of this guideline is to ensure that all non-text content is also available in text form. "Text form" refers to electronic text, not an image of text. Electronic text has the unique advantage that it can be rendered visually, auditorily, tactilely, or by any combination. As a result, information rendered in electronic text can be presented in whatever form best meets the needs of the user. It can also be easily enlarged, spoken in a voice that is easy to understand or rendered in whatever tactile form best meets the needs of a user.
Specific techniques for meeting each success criterion for this guideline are listed in the How to Meet sections for each success criterion (listed below). If there are techniques, however, for addressing this guideline that do not fall under any of the success criteria, they are listed here. These techniques are not required or sufficient for meeting any success criteria, but can make certain types of Web content more accessible to more people.
1.1.1 All non-text content has a text alternative that presents equivalent information, except for the situations listed below[begin delete]Except for the situations listed below, a text alternative that presents equivalent information is provided for all non-text content[end delete]. [LC-956] [LC-1281] [LC-1524] (Level 1)
[end change]Controls-Input: If non-text content is a control or accepts user input, then it has a name that describes its purpose. (See also Support compatibility with current and future user agents, including assistive technologies: ) [LC-738]
Media, Test, Sensory: If non-text content is multimedia [begin change],[end change] live audio-only or live video-only content[begin change],[end change] a [begin change]test or exercise that must be presented in non-text format [LC-1506] [end change] [begin change],[end change] or primarily intended to create a specific sensory experience [begin change],[end change] then text alternatives at least identify the non-text content with a descriptive text label. (For multimedia, see also Provide synchronized alternatives for multimedia: .) [LC-801]
CAPTCHA: If the purpose of non-text content is to confirm that content is being accessed by a person rather than a computer, [begin add]then [LC-738] [LC-1282] [end add] [begin change]a descriptive text label describing its purpose is provided and[end change] different forms are provided to accommodate [begin change]different [LC-800] [LC-1155] [end change] disabilities.
Decoration, Formatting, Invisible: If non-text content is pure decoration, or used only for visual formatting, or if it is not presented to users, [begin add]then [LC-738] [end add] it is implemented such that it can be ignored by assistive technology.
content that is not represented by a Unicode character or sequence of Unicode characters when rendered in a user agent according to the formal specification of the content type
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
text by which software can identify a component within Web content to the user
Note: The name may be hidden and only exposed by assistive technology, whereas a label is presented even without assistive technology. In many (but not all) cases, the label is a display of the name.
audio or video synchronized with another [begin delete]type of media[end delete] [begin add]format for presenting information[end add] and/or with time-based interactive components [LC-1499]
A time-based live presentation that contains only audio (no video and no interaction)
A time-based live presentation that contains only video (no audio and no interaction)
would be invalid if presented in text [LC-1506]
Example: Color blindness test, hearing test, vision exercise, spelling test.
a sensory experience that is not purely decorative and does not primarily convey important information or perform a function
Example: [begin add]Examples include a performance of a flute solo, works of visual art etc. [LC-1189] [end add]
text [begin delete], image, or sound[end delete] [begin add]or other component with a text alternative [end add] that is presented to a user to identify a component within Web content
serving only an aesthetic purpose, providing no information, and having no functionality.
a user agent that [begin add]both[end add]:
provides services beyond those offered by the host user agents to meet the requirements of users with disabilities. [begin change]Such[end change] services include alternative renderings (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)[begin add], and[end add] [LC-1178]
relies on services (such as retrieving Web content and parsing markup) provided by one or more other "host" user agents. Assistive technologies communicate data and messages with host user agents by using and monitoring APIs
Note 1: [begin add]In this definition, the host user agents are user agents in the general sense of the term. That is, any software that retrieves and renders Web content for users. The host user agent may provide important services to assistive technologies like retrieving Web content from program objects or parsing markup into identifiable bundles. [LC-732] [end add]
Note 2: [begin add]Host user agents may also provide services directly that meet the requirements of users with disabilities. [LC-732] [end add]
Note 3: This definition is based on User Agent Accessibility Guidelines 1.0 Glossary.
Example: Examples of assistive technologies that are important in the context of this document include the following:
screen magnifiers, [begin change]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 [LC-604] [end change] improve the visual readability of rendered text and images;
screen readers, which are used by people who are blind [begin change]to read textual information through synthesized speech or braille[end change];
text-to-speech software, which is used by some people with cognitive, language, and learning disabilities to convert text into synthetic speech;
[end add]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;
alternative pointing devices, which are used by people with certain physical disabilities to simulate mouse pointing and button activations.
Editorial Note: @@ Gregg and John to update this section to match new SC language. (15 March 2007)
The intent of this success criterion is to make information conveyed by non-text content accessible through the use of a text alternative. Text alternatives are a primary way for making information accessible because they can be rendered through any sensory modality (for example, visual, auditory or tactile) to match the needs of the user. Providing text alternatives allows the information to be rendered in a variety of ways by a variety of user agents. For example, a person who cannot see a picture can have the text alternative read aloud using synthesized speech. A person who cannot hear an audio file can have the text alternative displayed so that he or she can read it. In the future, text alternatives will also allow information to be more easily translated into sign language or into a simpler form of the same language.
Non-text content can take a number of forms, and this success criterion specifies how each is to be handled.
For non-text content that presents information, such as charts, diagrams, audio recordings, pictures, and animations, text alternatives can make the same information available in a form that can be rendered through any modality (for example, visual, auditory or tactile). Short and long text alternatives can be used as needed to convey the information in the non-text content. Note that pre-recorded audio-only and pre-recorded video-only files are covered here. Live -audio-only and Live -video-only files are covered below (see 3rd paragraph following this one).
For non-text content that responds to user input , such as images used as submit buttons or complex animations, text alternatives are provided if at all possible. If it is not possible to make the function available in any form of text (including with the use of links, etc.), then the purpose of the non-text content is identified in text so that the person at least knows what the non-text content is and why it is there.
Non-text content that is multimedia is made accessible through guideline 1.2. However it is important that users know what it is when they encounter it on a page so they can decide what action if any they want to take with it. A text alternative that describes the multimedia and/or gives its title is therefore provided.
Live Audio-only and live video-only files - It is much more difficult to provide text alternatives that convey the same information as live audio-only and live video-only content. For these types of non-text content, text alternatives provide a descriptive label.
Sometimes a test or exercise must use a particular sense. Audio or visual information is provided that cannot be changed to text because the test or exercise must be conducted using that sense. For example, a hearing test would be invalid if a text alternative were provided. A visual skill development exercise would similarly make no sense in text form. And a spelling test with text alternatives would not be very effective. For these cases, text alternatives should be provided to describe the purpose of the non-text content; of course, the text alternatives would not provide the same information needed to pass the test.
Sometimes content is primarily intended to create a specific sensory experience that words cannot fully capture. Examples include a symphony performance, works of visual art etc. [begin change]For such content, text alternatives at least identify the non-text content with a descriptive label and where possible, some descriptive text. If the reason for including the content in the page is known and can be described it is helpful to include that information. [LC-787] [end change]
Finally, there is non-text content that really is not meant to be seen or understood by the user. Transparent images used to move text over on a page; a one pixel transparent "web-bug" that tells the author when the page is viewed; and a swirl in the corner that conveys no information but just fills up a blank space to create an aesthetic effect are all examples of this. Putting alternative text on such items just distracts people using screen readers from the content on the page. Not marking the content in any way, though, leaves users guessing what the non-text content is and what information they may have missed (even though they have not missed anything in reality). This type of non-text content, therefore, is marked or implemented in a way that assistive technologies (AT) will ignore it and not present anything to the user.
This success criterion helps people who have difficulty perceiving visual content. Assistive technology can read text alternatives aloud, present them visually, or convert them to braille.
[end change]Text alternatives may help some people who have difficulty understanding the meaning of photographs, drawings, and other images (e.g. line drawings, graphic designs, paintings, three-dimensional representations), graphs, charts, animations, etc.
[end change]People who are deaf, are hard of hearing, or who are having trouble understanding audio information for any reason can read the text presentation. Research is ongoing regarding automatic translation of text into sign language. [LC-790]
People who are deaf-blind can read the text in braille.
Additionally, text alternatives support the ability to search for non-text content and to repurpose content in a variety of ways.
Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this criterion. The techniques listed only satisfy the success criterion if all of the WCAG 2.0 conformance requirements have been met.
Instructions: Select the situation below that matches your content. Each situation includes techniques or combinations of techniques that are known and documented to be sufficient for that situation.
G94: Providing short text alternative for non-text content that serves the same purpose and presents the same information as the non-text content USING a short text alternative technique listed below
G95: Providing short text alternatives that provide a brief description of the non-text content USING a short text alternative technique listed below AND one of the following techniques for long description:
G92: Providing long description for non-text content that serves the same purpose and presents the same information USING a long text alternative technique listed below
G82: Providing a text alternative that identifies the purpose of the functional non-text content USING a short text alternative technique listed below
Providing a descriptive label USING a short text alternative technique listed below
G68: Providing a descriptive label that describes the purpose of live audio-only and live video-only content USING a short text alternative technique listed below
G100: Providing the accepted name or a descriptive name of the non-text content USING a short text alternative technique listed below
Implementing or Marking the non-text content so that it will be ignored by AT USING one of the technology-specific techniques listed below
H36: Using alt attributes on images used as submit buttons (HTML)
H24: Providing text alternatives for the area elements of image maps (HTML)
[begin add]Providing text alternatives for strings where look-alike glyphs are used in place of letters (e.g. Leetspeak) (future link) [LC-796] [end add]
[begin add]Providing text alternatives for ASCII art (future link) [LC-796] [end add]
The following are common mistakes that are considered failures of Success Criterion 1.1.1 by the WCAG Working Group.
F3: Failure of SC 1.1.1 due to using CSS to include images that convey important information
[begin add]Failure of SC 1.1.1 due to using look-alike glyphs to represent text without providing a text alternative (future link) [LC-796] [end add]
[begin add]Failure of SC 1.1.1 due to using ASCII art without providing a text alternative (future link) [LC-796] [end add]
[begin add]Failure of SC 1.1.1 due to providing a title attribute without also providing a non-null alt attribute (future link) [LC-850] [end add]
Although not required for conformance, the following additional techniques should be considered in order to make content more accessible. Not all techniques can be used or would be effective in all situations.
Identifying informative non-text content (future link).
Keeping short descriptions short (future link).
Describing images that include text (future link).
Providing a longer description of the non-text content where only a descriptive label is required USING a technology-specific technique (for an accessibility-supported content technology) for long description listed above. (future link)
[begin change]Linking to textual information that provides comparable information (e.g. for a traffic Webcam, a municipality could provide a link to the text traffic report.) (future link) [LC-788] [end change]
Providing a transcript of a live audio only presentation after the fact (future link)
Writing for browsers that do not support frame (future link)
Providing alternative content for iframe (future link)
Providing text and non-text alternatives for object (future link)
Not using long descriptions for iframe (future link)
Providing redundant text links for client-side image maps (future link)
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 [begin add], trends and implications[end add] comparable to those available from the chart[begin delete], and provides the data in a table[end delete]. [begin add]Where possible and practical, the actual data is provided in a table. [LC-789] [end add]
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.
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. [begin change]Since the text of the tutorial already provides a full explanation, the text alternative has a brief description of the image and refers to the tutorial text for more information. [LC-1074] [end change]
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.
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."
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.
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.
[begin add]An e-learning application[end add]
[begin add]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. [end add] [LC-1326]
[begin add]A linked thumbnail image[end add]
[end add]A thumbnail image of the front page of a newspaper links to the home page of the "Smallville Times". The text alternative says "Smallville Times". [LC-858]
Resources are for information purposes only, no endorsement implied.
Excerpts from the NBA Tape Recording Manual, Third Edition. Information on describing complex images to people who are blind.
Inaccessibility of CAPTCHA. Examines a number of potential solutions that allow systems to test for human users while preserving access by users with disabilities. [LC-556]
[end add]The purpose of this guideline is to provide access to multimedia. Multimedia is defined in the glossary as:
multimedia: audio or video synchronized with another type of media and/or with time-based interactive components
Note that an audio file accompanied by interaction is covered here, as is a video-only file that involves interaction. These are covered because interaction must take place at a particular time. Having a text transcript that said, "for more information, click now," would not be very helpful since the reader would have no idea when the audio said, "now." As a result, synchronized captions would be needed.
Sometimes, there is so much dialogue that audio description cannot fit into existing pauses in the dialogue. The option at Level 1 to provide a full text alternative for multimedia including any interaction instead of audio description for multimedia would allow access to all of the information in the multimedia. This option also allows access to the visual information in non-visual form when audio description is not provided for some other reason.
For multimedia that includes interaction, interactive elements (for example links) could be embedded in the full text alternative for multimedia.
This guideline also includes (at Level 3) sign language interpretation for multimedia as well as an approach called extended audio description. In extended audio description, the video is frozen periodically to allow more audio description to take place than is possible in the existing pauses in the dialogue. [begin add]This is a case where higher-level success criteria build upon the requirements of lower-level SC with the intention of having cumulative, progressively stronger, requirements. [LC-1223] [end add]
Specific techniques for meeting each success criterion for this guideline are listed in the How to Meet sections for each success criterion (listed below). If there are techniques, however, for addressing this guideline that do not fall under any of the success criteria, they are listed here. These techniques are not required or sufficient for meeting any success criteria, but can make certain types of Web content more accessible to more people.
1.2.1 Captions are provided for prerecorded multimedia, [begin add]except for multimedia alternatives to text that are clearly labeled as such [LC-608] [end add]. (Level 1)
text presented and synchronized with multimedia to provide not only the speech, but also [begin change]non-speech information conveyed through sound, including meaningful sound effects and identification of speakers [LC-846] [end change]
Note: 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.
audio or video synchronized with another [begin delete]type of media[end delete] [begin add]format for presenting information[end add] and/or with time-based interactive components [LC-1499]
multimedia that presents no more information than is already presented in text (directly or via text alternatives) [LC-608]
[end add]Note: Multimedia alternatives to text are provided for those who benefit from alternate representations of text.
The intent of this success criterion is to enable people who are deaf or hard of hearing to watch multimedia presentations. Captions provide the part of the content available via the audio track. Captions not only include dialogue, but identify who is speaking and note important sounds.
It is acknowledged that at the present time there may be difficulty in creating captions for time-sensitive material and this may result in the author being faced with the choice of delaying the information until captions are available, or publishing time-sensitive content that is inaccessible to the deaf, at least for the interval until captions are available. Over time, the tools for captioning as well as building the captioning into the delivery process can shorten or eliminate such delays. [LC-1332]
[end add]Captions are not needed when the multimedia is, itself, an alternate presentation of information that is also presented via text on the Web page. For example, if information on a page is accompanied by a multimedia presentation that is easier for people with cognitive, language, or learning disabilities to understand, then it would not need to be captioned since the information is already presented on the page in text or in text alternatives (e.g. for images). [LC-608]
[end add]People who are deaf or have a hearing loss can access the auditory information in the multimedia content through captions.
Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this criterion. The techniques listed only satisfy the success criterion if all of the WCAG 2.0 conformance requirements have been met.
G87: Providing closed captions USING any readily available media format that has a video player that [begin delete]is free of charge and[end delete] supports closed captioning [LC-792]
G87: Providing closed captions USING any of the technology-specific techniques below
The following are common mistakes that are considered failures of Success Criterion 1.2.1 by the WCAG Working Group.
F8: Failure of SC 1.2.1 due to captions omitting some dialogue or important sound effects
Failure of SC 1.2.1 by providing multimedia without captions when the multimedia presents more information than is presented in its associated text. [LC-608]
[end add]Failure of SC 1.2.1 by not associating a multimedia alternative with its associated text. (future link) [LC-608]
[end add]Although not required for conformance, the following additional techniques should be considered in order to make content more accessible. Not all techniques can be used or would be effective in all situations.
Providing a note saying "No sound is used in this clip" for video-only clips (future link)
A captioned tutorial
A video clip shows how to tie a knot. The captions read,
"(music)
Using rope to tie knots was an important skill
for the likes of sailors, soldiers and woodsmen.."
From Sample Transcript Formatting by Whit Anderson.
A complex legal document contains multimedia clips for different paragraphs that show a person speaking the contents of the paragraph. Each clip is associated with its corresponding paragraph. No captions are provided for the multimedia. [LC-608]
[end add]An instruction manual containing a description of a part and its necessary orientation is accompanied by a multimedia clip showing the part in its correct orientation. No captions are provided for the multimedia clip. [LC-608]
[end add]Resources are for information purposes only, no endorsement implied.
(none currently documented)
1.2.2 Audio description of video, or a [begin change]full text alternative for multimedia including any interaction[end change] , is provided for prerecorded multimedia. (Level 1)
Note: [begin add]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. [LC-1224] [end add]
narration added to the soundtrack to describe important visual details that cannot be understood from the main soundtrack alone
Note 1: [begin change]Audio description of video provides information about actions, characters, scene changes, on-screen text, and other visual content. [LC-845] [end change]
Note 2: In standard audio description, narration is added during existing pauses in dialogue. (See also extended audio description.)
document including correctly sequenced descriptions of all visual settings, actions, and non-speech sounds combined with descriptive transcripts of all dialogue and a means of achieving any outcomes that are achieved using interaction during the multimedia
Note: A screenplay used to create the multimedia content would meet this definition only if it was corrected to accurately represent the final multimedia after editing.
audio or video synchronized with another [begin delete]type of media[end delete] [begin add]format for presenting information[end add] and/or with time-based interactive components [LC-1499]
The intent of this success criterion is to provide people who are blind or visually impaired access to the visual information in a multimedia presentation. This success criterion describes two approaches, either of which can be used.
One approach is to provide audio description of the video content. The audio description augments the audio portion of the presentation with the information needed when the video portion is not available. During existing pauses in dialogue, audio description provides information about actions, characters, scene changes, and on-screen text that are important and are not described or spoken in the main sound track.
The second approach involves providing all of the information in the multimedia (both visual and auditory) in text form. A full text alternative for multimedia including any interaction provides a running description of all that is going on in the multimedia content. The full text alternative for multimedia including any interaction reads something like a screenplay or book. Unlike audio description, the description of the video portion are not constrained to just the pauses in the existing dialogue. Full descriptions are provided of all visual information, including visual context, actions and expressions of actors, and any other visual material. In addition, non-speech sounds (laughter, off-screen voices, etc.) are described, and transcripts of all dialogue are included. The sequence of description and dialogue transcripts are the same as the sequence in the multimedia itself. As a result, the full text alternative for multimedia can provide a much more complete representation of the multimedia content than audio description alone.
If there is any interaction as part of the multimedia presentation (e.g. "press now to answer the question") then the full text alternative for multimedia would provide hyperlinks or whatever is needed to provide parallel functionality.
Note: [begin add]For 1.2.2, 1.2.3, 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. [LC-1224] [end add]
This success criterion may help some people who have difficulty watching video or other multimedia content, including people who have difficulty perceiving or understanding moving images.
[end change]Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this criterion. The techniques listed only satisfy the success criterion if all of the WCAG 2.0 conformance requirements have been met.
G69: Providing a full multimedia text alternative including any interaction
G78: Providing a sound track that includes audio description as the primary sound track
G78: Providing a sound track that includes audio description AND associating it with the multimedia content using one of the following techniques:
Providing audio description in its own sound track (future link) AND merging the description track with the original soundtrack of the multimedia content at runtime using one of the following techniques
Using SMIL 1.0 to merge a description track with sound track (future link)
Using SMIL 2.0 to merge a description track with sound track (future link)
The following are common mistakes that are considered failures of Success Criterion 1.2.2 by the WCAG Working Group.
(No failures currently documented)
Although not required for conformance, the following additional techniques should be considered in order to make content more accessible. Not all techniques can be used or would be effective in all situations.
Providing audio description in multiple languages in SMIL 1.0 (future link)
Providing audio description in multiple languages in SMIL 2.0 (future link)
A movie with audio description.
Describer: A title, "Teaching Evolution Case Studies. Bonnie Chen." A teacher shows photographs of birds with long, thin beaks.
Bonnie Chen: "These photos were all taken at the Everglades."
Describer: The teacher hands each student two flat, thin wooden sticks.
Bonnie Chen: "Today you will pretend to be a species of wading bird that has a beak like this."
Describer: The teacher holds two of the sticks to her mouth making the shape of a beak.
Transcript of audio based on the first few minutes of "Teaching Evolution Case Studies, Bonnie Chen" (copyright WGBH and Clear Blue Sky Productions, Inc.)
A full text alternative for multimedia including any interaction for a training video
A company purchases a Training video for use by its employees and puts it on the companies intranet. The video involves explaining use of a new technology and has a person talking and showing things at the same time. Since there is no place to insert audio description of the visual demonstrations during gaps in dialogue, the company provides a full text alternative for multimedia that all employees, including those who cannot see the demonstrations, can use to better understand what is being presented.
Resources are for information purposes only, no endorsement implied.
1.2.3 Captions are provided for live multimedia. (Level 2)
Note: [begin add]If multimedia is completely computer generated, it is not live and is subject to the requirements for pre-recorded multimedia in WCAG 2.0. [LC-925] [end add]
text presented and synchronized with multimedia to provide not only the speech, but also [begin change]non-speech information conveyed through sound, including meaningful sound effects and identification of speakers [LC-846] [end change]
Note: 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.
audio or video synchronized with another [begin delete]type of media[end delete] [begin add]format for presenting information[end add] and/or with time-based interactive components [LC-1499]
The intent of this success criterion is to enable people who are deaf or hard of hearing to watch real-time presentations. Captions provide the part of the content available via the audio track. Captions not only include dialogue, but also identify who is speaking and notate sound effects and other significant audio.
People who are deaf or have a hearing loss can access the auditory information in the multimedia content through captions.
Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this criterion. The techniques listed only satisfy the success criterion if all of the WCAG 2.0 conformance requirements have been met.
G9: Creating captions for live multimedia AND G93: Providing open (always visible) captions
G9: Creating captions for live multimedia AND G87: Providing closed captions USING any readily available media format that has a video player that [begin delete]is free of charge and[end delete] supports closed captioning [LC-792]
G9: Creating captions for live multimedia AND G87: Providing closed captions USING one of the following techniques:
Note: Captions may be generated using real-time text translation service. [begin delete](stenographic or, in the future, speech-to-text with corrections)[end delete] [LC-790]
The following are common mistakes that are considered failures of Success Criterion 1.2.3 by the WCAG Working Group.
(No failures currently documented)
Although not required for conformance, the following additional techniques should be considered in order to make content more accessible. Not all techniques can be used or would be effective in all situations.
(none currently documented)
A Web cast
A news organization provides a live, captioned Web cast.
Resources are for information purposes only, no endorsement implied.
(none currently documented)
See How to Meet Success Criterion 1.2.1 (Captions (Prerecorded)) .
1.2.4 Audio description of video is provided for prerecorded multimedia. (Level 2)
narration added to the soundtrack to describe important visual details that cannot be understood from the main soundtrack alone
Note 1: [begin change]Audio description of video provides information about actions, characters, scene changes, on-screen text, and other visual content. [LC-845] [end change]
Note 2: In standard audio description, narration is added during existing pauses in dialogue. (See also extended audio description.)
audio or video synchronized with another [begin delete]type of media[end delete] [begin add]format for presenting information[end add] and/or with time-based interactive components [LC-1499]
The intent of this success criterion is to provide people who are blind or visually impaired access to the visual information in a multimedia presentation. The audio description augments the audio portion of the presentation with the information needed when the video portion is not available. During existing pauses in dialogue, audio description provides information about actions, characters, scene changes, and on-screen text that are important and are not described or spoken in the main sound track.
Note: [begin add]For 1.2.2, 1.2.3, 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. [LC-1224] [end add]
People who are blind or have low vision as well as those with cognitive limitations who have difficulty interpreting visually what is happening benefit from audio description of visual information.
Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this criterion. The techniques listed only satisfy the success criterion if all of the WCAG 2.0 conformance requirements have been met.
G78: Providing a sound track that includes audio description as the primary sound track
G78: Providing a sound track that includes audio description AND associating it with the multimedia content using one of the following techniques:
Providing audio description in its own sound track (future link) AND merging the description track with the original soundtrack of the multimedia content at runtime using one of the following techniques
Using SMIL 1.0 to merge a description track with sound track (future link)
Using SMIL 2.0 to merge a description track with sound track (future link)
The following are common mistakes that are considered failures of Success Criterion 1.2.4 by the WCAG Working Group.
(No failures currently documented)
Although not required for conformance, the following additional techniques should be considered in order to make content more accessible. Not all techniques can be used or would be effective in all situations.
Providing audio description in multiple languages in SMIL 1.0 (future link)
Providing audio description in multiple languages in SMIL 2.0 (future link)
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.)
Resources are for information purposes only, no endorsement implied.
1.2.5 Sign language interpretation is provided for multimedia. (Level 3)
translation of one language, generally a spoken language, into a sign language [LC-741]
Note: [begin delete]Most[end delete] [begin add]True[end add] sign languages are independent languages that are unrelated to the spoken language(s) of the same country or region. [LC-1504]
audio or video synchronized with another [begin delete]type of media[end delete] [begin add]format for presenting information[end add] and/or with time-based interactive components [LC-1499]
The intent of this success criterion is to enable people who are deaf or hard of hearing and who are fluent in a sign language to understand the content of the audio track of multimedia presentations. Written text, such as that found in captions, is often a second language. Some individuals will require sign language interpretation to gain full access to the multimedia content. [LC-591]
[end change]People whose human language is a sign language sometimes have limited reading ability. These individuals may not be able to read and comprehend the captions and thus require a sign language interpretation to gain access to the multimedia content.
Some people who communicate using sign language and are proficient readers may have impaired vision which may make it difficult to read the captions on the screen. A sign language interpretation may be easier to view. [LC-596]
Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this criterion. The techniques listed only satisfy the success criterion if all of the WCAG 2.0 conformance requirements have been met.
G54: Including a sign language interpreter in the corner of the video stream
Providing a new page that has the video with the sign language interpretation of the audio track. (future link) [LC-593]
[end add]G81: Providing a synchronized video of the sign language interpreter that can be displayed in a different viewport or overlaid on the image by the player USING one of the following techniques
The following are common mistakes that are considered failures of Success Criterion 1.2.5 by the WCAG Working Group.
(No failures currently documented)
Although not required for conformance, the following additional techniques should be considered in order to make content more accessible. Not all techniques can be used or would be effective in all situations.
(none currently documented)
Example 1. A corporation is making an important announcement to all of its employees. The meeting will be held in the main headquarters and streamed to the Web. A sign language interpreter is provided at the meeting location. The live video includes a full view of the sign language interpreter as well as the person presenting.
Example 2. The same announcement described in example 1 is also Webcast to remote employees. Since there is only one display available for this, the sign language interpreter is shown in the corner of the display.
Example 3. A university is providing an on-line version of a particular lecture by creating a multimedia presentation of the professor delivering the lecture. The presentation includes video of the professor speaking and demonstrating a science experiment. A sign language interpretation of the lecture is created and presented on the Web with the multimedia version.
Resources are for information purposes only, no endorsement implied.
National Institute on Deafness and other Communication Disorders: Information on American Sign Language
1.2.6 Extended audio description of video is provided for prerecorded multimedia. (Level 3)
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.
audio or video synchronized with another [begin delete]type of media[end delete] [begin add]format for presenting information[end add] and/or with time-based interactive components [LC-1499]
The intent of this success criterion is to provide people who are blind or visually impaired access to a multimedia presentation beyond that which can be provided by standard audio description. This is done by periodically freezing the multimedia presentation and playing additional audio description. The multimedia presentation is then resumed.
Because it disrupts viewing for those who do not need the additional description, techniques that allow you to turn the feature on and off are often provided. Alternately, versions with and without the additional description can be provided.
People who are blind, people with low vision who cannot see the screen, as well as those with cognitive limitations who have difficulty interpreting visually what is happening, often use audio description of the visual information. However, if there is too much dialogue the audio description is insufficient. Extended audio description can provide the additional information they needed to understand the video.
Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this criterion. The techniques listed only satisfy the success criterion if all of the WCAG 2.0 conformance requirements have been met.
[begin add]Providing a second version of the movie with extended audio descriptions during halted video segments (future link)[end add]
G8: Creating an extended audio description for the multimedia content USING one of the following techniques
The following are common mistakes that are considered failures of Success Criterion 1.2.6 by the WCAG Working Group.
(No failures currently documented)
Although not required for conformance, the following additional techniques should be considered in order to make content more accessible. Not all techniques can be used or would be effective in all situations.
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.
Resources are for information purposes only, no endorsement implied.
1.2.7 [begin delete]For prerecorded multimedia, [end delete]A [begin change]full text alternative for multimedia including any interaction[end change] is provided [begin add]for all prerecorded multimedia [LC-1156] [end add]. (Level 3)
document including correctly sequenced descriptions of all visual settings, actions, and non-speech sounds combined with descriptive transcripts of all dialogue and a means of achieving any outcomes that are achieved using interaction during the multimedia
Note: A screenplay used to create the multimedia content would meet this definition only if it was corrected to accurately represent the final multimedia after editing.
The intent of this success criterion is to make audio visual material available to individuals whose vision is too poor to reliably read captions and whose hearing is too poor to reliably hear dialogue and audio description. This is done by providing a full text alternative for multimedia including any interaction.
This approach involves providing all of the information in the multimedia (both visual and auditory) in text form. A full text alternative for multimedia including any interaction provides a running description of all that is going on in the multimedia content. The full text alternative for multimedia reads something like a book. Unlike audio description, the description of the video portion is not constrained to just the pauses in the existing dialogue. Full descriptions are provided of all visual information, including visual context, actions and expressions of actors, and any other visual material. In addition, non-speech sounds (laughter, off-screen voices, etc.) are described, and transcripts of all dialogue are included. The sequence of descriptions and dialogue transcripts is the same as the sequence in the multimedia itself. As a result, the full text alternative for multimedia can provide a much more complete representation of the multimedia content than audio description alone.
If there is any interaction as part of the multimedia presentation (e.g. "press now to answer the question") then the full text alternative for multimedia would provide hyperlinks or whatever is needed to provide parallel functionality.
Individuals whose vision is too poor to reliably read captions and whose hearing is too poor to reliably hear dialogue can access the full text alternative for multimedia by using a refreshable braille display.
Note: [begin add]For 1.2.2, 1.2.3, 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. [LC-1224] [end add]
People who cannot see well or at all and who also cannot hear well or at all can get access to information in audio-visual presentations.
Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this criterion. The techniques listed only satisfy the success criterion if all of the WCAG 2.0 conformance requirements have been met.
G69: Providing a full multimedia text alternative including any interaction USING one of the following techniques
Linking to the full text alternative for multimedia including any interaction USING one of the following techniques
The following are common mistakes that are considered failures of Success Criterion 1.2.7 by the WCAG Working Group.
(No failures currently documented)
Although not required for conformance, the following additional techniques should be considered in order to make content more accessible. Not all techniques can be used or would be effective in all situations.
Example 1. full text alternative for multimedia for a training video
A community center purchases a Training video for use by its clients and puts it on the center’s intranet. The video involves explaining use of a new technology and has a person talking and showing things at the same time. The community center provides a full text alternative for multimedia that all clients, including those who can neither see the demonstrations nor hear the explanations in the multimedia, can use to better understand what is being presented.
Resources are for information purposes only, no endorsement implied.
(none currently documented)
The purpose of this guideline is to ensure that all information is available in a form that can be perceived by all users. If all of the information is available in a form that can be determined by software, then it can be presented to users in different ways (visually, audibly, tactilely etc.). If information is embedded in a particular presentation in such a way that the [begin add]structure and[end add] information cannot be [begin delete]separated from the presentation[end delete] [begin add]programmatically determined by the assistive technology[end add], then it cannot be rendered in other formats as needed by the user. [LC-1201]
The success criteria under this guideline all seek to ensure that different types of information that are often encoded in presentation are also available so that they can be presented in other modalities.
Specific techniques for meeting each success criterion for this guideline are listed in the How to Meet sections for each success criterion (listed below). If there are techniques, however, for addressing this guideline that do not fall under any of the success criteria, they are listed here. These techniques are not required or sufficient for meeting any success criteria, but can make certain types of Web content more accessible to more people.
Providing resizable text (future link)
1.3.1 Information and relationships conveyed through presentation can be programmatically determined [begin add]or are available in text [LC-742] [end add], and notification of changes to these is available to user agents, including assistive technologies. (Level 1)
[begin add]meaningful associations between distinct pieces of content [LC-1427] [end add]
[begin delete]rendering of the content and structure in a form that can be perceived by the user[end delete] [begin change]rendering of the content in a form to be perceived by users [LC-490] [LC-1501] [end change]
determined by software from [begin add]author-supplied[end add] data provided in a [begin delete] user-agent-supported manner such that the[end delete] [begin add]way that different[end add] user agents, including assistive technologies, can extract and present this information to users in different modalities [LC-756] [LC-1502]
Example: Determined in a mark-up language from elements and attributes that are accessed directly by commonly available assistive technology.
[end add]Example: Determined from technology-specific data structures in a non-mark-up language and exposed to assistive technology via an accessibility API that is supported by commonly available assitive technology.
[end add]any software that retrieves and renders Web content for users
Example: Web browsers, media players, plug-ins, and other programs — including assistive technologies — that help in retrieving[begin change], rendering, and interacting with [end change]Web content. [LC-1269]
a user agent that [begin add]both[end add]:
provides services beyond those offered by the host user agents to meet the requirements of users with disabilities. [begin change]Such[end change] services include alternative renderings (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)[begin add], and[end add] [LC-1178]
relies on services (such as retrieving Web content and parsing markup) provided by one or more other "host" user agents. Assistive technologies communicate data and messages with host user agents by using and monitoring APIs
Note 1: [begin add]In this definition, the host user agents are user agents in the general sense of the term. That is, any software that retrieves and renders Web content for users. The host user agent may provide important services to assistive technologies like retrieving Web content from program objects or parsing markup into identifiable bundles. [LC-732] [end add]
Note 2: [begin add]Host user agents may also provide services directly that meet the requirements of users with disabilities. [LC-732] [end add]
Note 3: This definition is based on User Agent Accessibility Guidelines 1.0 Glossary.
Example: Examples of assistive technologies that are important in the context of this document include the following:
screen magnifiers, [begin change]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 [LC-604] [end change] improve the visual readability of rendered text and images;
screen readers, which are used by people who are blind [begin change]to read textual information through synthesized speech or braille[end change];
text-to-speech software, which is used by some people with cognitive, language, and learning disabilities to convert text into synthetic speech;
[end add]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;
alternative pointing devices, which are used by people with certain physical disabilities to simulate mouse pointing and button activations.
The intent of this success criterion is to ensure that information and relationships that are implied by visual or auditory formatting are preserved when the presentation format changes. For example, the presentation format changes when the content is read by a screen reader or when a user style sheet is substituted for the style sheet provided by the author.
Sighted users perceive structure through various visual cues — headings are often in a larger, bold font separated from paragraphs by blank lines; list items are preceded by a bullet and perhaps indented; paragraphs are separated by a blank line; items that share a common characteristic are organized into tabular rows and columns; form fields may be positioned as groups that share text labels; a different background color may be used to indicate that several items are related to each other; [begin add]words that have special status are indicated by changing the font family and /or bolding, italicizing, or underlining them [end add]and so on [LC-588] .
Auditory cues may be used as well. For example, a chime might indicate the beginning of a new section; a change in voice pitch or speech rate may be used to emphasize important information or to indicate quoted text; etc.
When such relationships are perceivable to one set of users, those relationships can be made to be perceivable to all. [begin add]One method of determining whether or not information has been properly provided to all users is to access the information serially in different modalities.[end add]
[end change]If links to glossary items are implemented using anchor elements (or the proper link element for the technology in use) and identified using a different font face, a screen reader user will hear that the item is a link when the glossary term is encountered even though they may not receive information about the change in font face. An on-line catalog may indicate prices using a larger font colored red. A screen reader or person who can not perceive red, still has the information about the price as long as it is preceded by the currency symbol.
[end add]Some technologies do not provide a means to programmatically determine some types of information and relationships. In that case then there should be a text description of the information and relationships. For instance, "all required fields are marked with an asterisk (*)". The text description should be near the information it is describing (when the page is linearized), such as in the parent element or in the adjacent element.
[end add]This success criterion helps people with different disabilities by allowing user agents to adapt content according to the needs of individual users.
[end change]Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this criterion. The techniques listed only satisfy the success criterion if all of the WCAG 2.0 conformance requirements have been met.
Instructions: Select the situation below that matches your content. Each situation includes techniques or combinations of techniques that are known and documented to be sufficient for that situation.
Separating information and structure from presentation to enable modification of presentation without altering content (future link) [LC-1201]
[end add]Making information and relationships conveyed through presentation programmatically determinable USING the following techniques:
H72: Using p for paragraphs (HTML)
Making information and relationships conveyed through presentation programmatically determinable or available in text USING the following techniques:
[begin add]Presenting tabular information in plain text (future link) [LC-672] [end add]
The following are common mistakes that are considered failures of Success Criterion 1.3.1 by the WCAG Working Group.
[begin change]F17: Failure of SC 1.3.1 due to insufficient information in DOM to determine one-to-one relationships (e.g., between labels with same id) in HTML[end change]
F42: Failure of SC 1.3.1 due to using scripting events to emulate links
F48: Failure of SC 1.3.1 due to using the pre element to markup tabular information
[begin change]F62: Failure of SC 1.3.1 due to insufficient information in DOM to determine specific relationships in XML[end change]
Although not required for conformance, the following additional techniques should be considered in order to make content more accessible. Not all techniques can be used or would be effective in all situations.
Using CSS styles to change or enhance the presentation of structure (future link)
[begin add]Using CSS rather than tables for page layout (future link) [end add] [LC-509]
[begin add]Positioning labels to maximize predictability of relationships[end add] [LC-758]
[begin add] SCR25: Using Dynamic Web Content Accessibility to programmatically identify form fields as required (SCRIPT) [LC-938] [end add]
Providing labels for all form controls that do not have implicit labels (future link) [LC-654]
[end add][begin change]A form with required fields[end change]
[begin change]A form contains several required fields. The labels for the required fields are displayed in red. In addition, at the end of each label is an asterisk character, *. The instructions for completing the form indicate that "all required fields are displayed in red and marked with an asterisk *", followed by an example. [LC-1079] [end change]
A form that uses color and text to indicate required fields
A form contains both required and optional fields. Instructions at the top of the form explain that required fields are labeled with red text and also with an icon whose text alternative says, “Required.” . Both the red text and the icon are programmatically associated with the appropriate form fields so that assistive technology users can determine the required fields. [LC-1079]
A bus schedule table where the headers for each cell can be programmatically determined
A bus schedule consists of a table with the bus stops listed vertically in the first column and the different buses listed horizontally across the first row. Each cell contains the time when the bus will be at that bus stop. The bus stop and bus cells are identified as headers for their corresponding row or column so that assistive technology can programmatically determine which bus and which bus stop are associated with the time in each cell.
A form where the labels for the checkboxes can be programmatically determined
In a form, the labels for each checkbox can be programmatically determined by assistive technology.
A text document
A simple text document is formatted with double blank lines before titles, asterisks to indicate list items and other standard formatting conventions so that its structure can be programmatically determined.
1.3.2 Any information that is conveyed by color [begin add]differences[end add] is also visually evident without [begin delete]color[end delete] [begin add]the color differences[end add]. [LC-742] (Level 1)
information presented in a manner that depends entirely on the ability to perceive color
The intent of this success criterion is to ensure that all users can access information that is conveyed by color. If the information is conveyed through color in an image (or other non-text format), the color cannot be programmatically determined by assistive technology. In this case, providing the information conveyed with color through another means ensures that assistive technology users who cannot see the color can still perceive the information.
Color is an important asset in design of Web content, enhancing its aesthetic appeal, its usability, and its accessibility. However, some users have difficulty perceiving color. People with partial sight often experience limited color vision, and many older users do not see color well. In addition, people using text-only, limited-color or monochrome displays and browsers will be unable to access information that is presented only in color.
This success criterion benefits people with visual disabilities:Users with partial sight often experience limited color vision.
Users who are blind (using a screen reader) benefit when information conveyed through color is also available in text (including text alternatives for images that use color to convey information).
Some older users may not be able to see color well.
Users who have color-blindness benefit when information conveyed by color is available in other visual ways.
Users with visual disabilities as well as limited hearing may be unable to access color-dependent information.
Users who are deaf-blind using braille (text) refreshable displays may be unable to access color-dependent information.
People using text-only, limited color or monochrome displays may be unable to access color-dependent information.
Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this criterion. The techniques listed only satisfy the success criterion if all of the WCAG 2.0 conformance requirements have been met.
Instructions: Select the situation below that matches your content. Each situation includes techniques or combinations of techniques that are known and documented to be sufficient for that situation.
The following are common mistakes that are considered failures of Success Criterion 1.3.2 by the WCAG Working Group.
Although not required for conformance, the following additional techniques should be considered in order to make content more accessible. Not all techniques can be used or would be effective in all situations.
A form that uses color and text to indicate required fields
A form contains both required and optional fields. Instructions at the top of the form explain that required fields are labeled with red text and also with an icon whose text alternative says, “Required.” . Both the red text and the icon are programmatically associated with the appropriate form fields so that assistive technology users can determine the required fields.
An examination.
Students view an SVG image of a chemical compound and identify the chemical elements present based on the colors used in the diagram. The text alternatives associated with each element name the color of the element and indicate the element's position in the diagram. Students who cannot perceive color have the same information about the compound as their classmates. (This technique also satisfies Guideline 1.1 Level 1.)
Disabled Form elements.
[begin add]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.[end add] [LC-717]
Resources are for information purposes only, no endorsement implied.
(none currently documented)
1.3.3 [begin change]When the sequence in which content is presented affects its meaning, a correct reading sequence[end change] can be programmatically determined [begin add]and sequential navigation of interactive components is consistent with that sequence[end add]. [LC-1159] [LC-816] (Level 1)
determined by software from [begin add]author-supplied[end add] data provided in a [begin delete] user-agent-supported manner such that the[end delete] [begin add]way that different[end add] user agents, including assistive technologies, can extract and present this information to users in different modalities [LC-756] [LC-1502]
Example: Determined in a mark-up language from elements and attributes that are accessed directly by commonly available assistive technology.
[end add]Example: Determined from technology-specific data structures in a non-mark-up language and exposed to assistive technology via an accessibility API that is supported by commonly available assitive technology.
[end add]The intent of this success criterion is to enable a user agent to provide an alternative presentation of content while preserving the reading order needed to perceive meaning. It is important that it be possible to programmatically determine at least one sequence of the content that makes sense. [begin add]Content that does not meet this success criterion may confuse or disorient users when assistive technology reads the content in the wrong order, or when alternate style sheets or other formatting changes are applied.[end add]
A sequence is meaningful if the order of content in the sequence cannot be changed without affecting its meaning. [begin delete]The order of words in sentences and sentences in paragraphs, for instance, is always meaningful. [LC-795] [end delete] [begin change]For example[end change], if a page contains two independent articles, the relative order of the articles may not affect their meaning, as long as they are not interleaved. In such a situation, the articles themselves may have meaningful sequence, but the container that contains the articles may not have a meaningful sequence.
The semantics of some elements define whether or not their content is a meaningful sequence. For instance, in HTML, text is always a meaningful sequence. Tables and ordered lists are meaningful sequences, but unordered lists are not.
This success criterion may help people who rely on assistive technologies that read content aloud. The meaning evident in the sequencing of the information in the default presentation will be the same when the content is presented in spoken form.
Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this criterion. The techniques listed only satisfy the success criterion if all of the WCAG 2.0 conformance requirements have been met.
G57: Ordering the content in a meaningful sequence for all the content in the Web page
Marking sequences in the content as meaningful USING one of the following techniques AND G57: Ordering the content in a meaningful sequence for those sequences
The following are common mistakes that are considered failures of Success Criterion 1.3.3 by the WCAG Working Group.
Although not required for conformance, the following additional techniques should be considered in order to make content more accessible. Not all techniques can be used or would be effective in all situations.
Using left-justified text for languages that are written left to right and right-justified text for languages that are written right-to-left (future link) [LC-840]
[end add]Using appropriate justification for languages that are written right-to-left (future link) [LC-840]
[end add]Providing a link to linearized rendering (future link)
Providing a style switcher between style sheets that affect presentation order (future link)
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.
1.3.4 [begin delete]Information required to understand and operate content does[end delete] [begin add]Instructions provided for understanding and operating content do[end add] not rely on shape, size, visual location, or orientation of components. [LC-1160] [LC-640] (Level 1)
The intent of this success criterion is to ensure that all users can access instructions for using the content, even when they cannot perceive shape or size or use information about spatial location or orientation. Some content relies on knowledge of the shape or position of objects that are not available from the structure of the content (for example, "round button" or "button to the right"). Some users with disabilities are not able to perceive shape or position due to the nature of the assistive technologies they use. This success criterion requires that additional information be provided to clarify anything that is dependent on this kind of information.
Providing information using shape and/or location, however, is an effective method for many users including those with cognitive limitations. This provision should not discourage those types of cues as long as the information is also provided in other ways.
People who are blind and people who have low vision may not be able to understand information if it is conveyed by shape and/or location. Providing additional information other than shape and/or location will allow them to understand the information conveyed by shape and/or alone.
Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this criterion. The techniques listed only satisfy the success criterion if all of the WCAG 2.0 conformance requirements have been met.
The following are common mistakes that are considered failures of Success Criterion 1.3.4 by the WCAG Working Group.
Although not required for conformance, the following additional techniques should be considered in order to make content more accessible. Not all techniques can be used or would be effective in all situations.
Using an image with a text alternative for graphical symbols instead of a Unicode font glyph with the desired graphical appearance but different meaning (future link) [LC-798]
[end change][begin add]Example 1: A schedule of competitive events uses color and shape to distinguish the time of each event[end add]
[begin add]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.[end add] [LC-1082]
[begin add]Example 2: An online multi-page survey [end add]
[begin add]An online multi-page survey uses a link implemented as a green arrow icon placed in the lower right hand corner of the content to move from one survey page to the next. The arrow is clearly labeled with "Next" and the instructions state, "To move to the next section of the survey, select the green arrow icon labeled 'Next' in the lower right below the last survey question." This example uses both positioning, color and labeling to help identify the icon.[end add] [LC-1082]
1.3.5 Information that is conveyed by variations in presentation of text is also conveyed in text, or the variations in presentation of text can be programmatically determined. [LC-588] (Level 2)
changes in the visual appearance or sound of the text[begin change]; or, if auditory presentation is specified in the content, changes in the sound of text such as voice.[end change] [begin delete], such as changing to a different font or a different voice[end delete] [LC-852]
determined by software from [begin add]author-supplied[end add] data provided in a [begin delete] user-agent-supported manner such that the[end delete] [begin add]way that different[end add] user agents, including assistive technologies, can extract and present this information to users in different modalities [LC-756] [LC-1502]
Example: Determined in a mark-up language from elements and attributes that are accessed directly by commonly available assistive technology.
[end add]Example: Determined from technology-specific data structures in a non-mark-up language and exposed to assistive technology via an accessibility API that is supported by commonly available assitive technology.
[end add]The intent of this success criterion is to make information conveyed by varying the presentation of text available even if the information is presented in an alternative modality or if the person cannot perceive the text variations.
In a visual medium, examples of variations in the presentational of text would include:
emphasizing some words by bolding, italicizing or underlining them;
indicating content headings by increased font size and bolding font;
emphasizing words or indicating that they have special status (such as a key term) by changing the font family used to present them;
conveying information by raising characters (or words) above centerline in a line of text.
Users of screen readers or refreshable braille displays may be unable to access information conveyed by the formatting of text.
People with decreased visual perception, including some older users, may not see text formatting well.
Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this criterion. The techniques listed only satisfy the success criterion if all of the WCAG 2.0 conformance requirements have been met.
Marking emphasized or special text USING one of the following techniques:
The following are common mistakes that are considered failures of Success Criterion 1.3.4 (REMOVED) by the WCAG Working Group.
Although not required for conformance, the following additional techniques should be considered in order to make content more accessible. Not all techniques can be used or would be effective in all situations.
[begin delete]Ensure that numerals or other look alike glyphs are not used in place of letters (future link) [LC-796] [end delete]
use the correct character
In English, the shapes of some characters, such as '0' (zero) and 'O' (o), or '1' (one) and 'l' (l), resemble one another. Languages such as Japanese and Chinese have many similar looking characters that are often mistakenly used for one another. In Japanese, for example, characters such as 'ー' (Tyou-on), '―' (Zenkaku dash), and '－' (Zenkaku minus) all have similar appearances. Since the method of input for Japanese characters converts all of these characters from the same character '-', these characters are often misused in Japanese. The Japanese word "リード" is a correct word that means "lead" in English, while " リ―ド" is not a word at all. Sighted users do not notice this error, while users who use a screen reader cannot understand text containing such a substitution.
While some guidelines are focused on making information available in a form that can be presented in alternate formats, this guideline is concerned with making the default presentation as usable as possible to people with disabilities. The primary focus is on making it easier for users to separate foreground information from the background. For visual presentations this involves making sure that information presented on top of a background contrasts sufficiently with the background. For audio presentations this involves making sure that foreground sounds are sufficiently louder than the background sounds. Individuals with visual and hearing disabilities have much greater difficulty separating foreground and background information.
Specific techniques for meeting each success criterion for this guideline are listed in the How to Meet sections for each success criterion (listed below). If there are techniques, however, for addressing this guideline that do not fall under any of the success criteria, they are listed here. These techniques are not required or sufficient for meeting any success criteria, but can make certain types of Web content more accessible to more people.
Using readable fonts (future link)
1.4.1 [begin change]If any audio plays automatically for more than 3 seconds, [begin add]either a mechanism is available to pause or stop the audio, or a mechanism is available to control audio volume which can be set independently of the system volume.[end add] [begin delete]mechanism is available to turn it off without requiring the user to turn off all system audio.[end delete] [LC-1162] [LC-1286] [LC-1085] [LC-1237] [end change] (Level 1)
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. [LC-619]
Individuals who use screen reading software can find it hard to understand the speech output if there is other audio playing at the same time. This difficulty is exacerbated when the screen reader's speech output is software based (as most are today) and is controlled via the same volume control as the sound.
Individuals who use screen reading technologies can hear the screen reader without other sounds playing. This is especially important for those who are hard of hearing and for those whose screen readers use the system volume (so they cannot turn sound down and screen reader up).
This success criterion also benefits people who have difficulty focusing on visual content (including text) when audio is playing.
[end change]Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this criterion. The techniques listed only satisfy the success criterion if all of the WCAG 2.0 conformance requirements have been met.
G60: Playing a sound that turns off automatically within three seconds
Playing sounds only on user request (future link)
Providing a control near the top of the Web page that turns off sounds that play automatically (future link)
Providing a user interface control to pause or stop multimedia (future link) [LC-1286]
[end add]The following are common mistakes that are considered failures of Success Criterion 1.4.1 by the WCAG Working Group.
Although not required for conformance, the following additional techniques should be considered in order to make content more accessible. Not all techniques can be used or would be effective in all situations.
Providing a sitewide preference to turn off audio in addition to providing a control near the top of the Web page that turns off sounds that play automatically (future link)
An audio file begins playing automatically when a page is opened. However, the audio can be stopped by the user by selecting a "silent" link at the top of the page.
An audio file begins playing automatically when a page is opened. However, the audio can be stopped by the user by selecting a "silent" link at the top of the page.
[begin add]A Flash splash page with sound that plays and then stops in less than 3 seconds. [LC-794] [end add]
[begin add]A Flash splash page with sound that plays that can be turned off. [LC-794] [end add]
1.4.2 Text and images of text[begin delete], and lines in diagrams[end delete] have a contrast ratio of at least 5:1 with their background. Text or images of text may have a contrast ratio of at least 3:1 where all of the following are true: [LC-511] (Level 2)
[end change]Text is at least twice the height of the body text; and
the text has a stem width of at least three times the stem width of the body text; and
the text is presented over a non-patterned background.
Note: This requirement does not apply to text or images of text that are pure decoration.
(L1 + 0.05) / (L2 + 0.05), where L1 is the [begin change]relative luminance [LC-580] [end change] of the lighter of the [begin change]foreground [LC-1182] [end change] or background colors, and L2 is the [begin change]relative luminance [LC-580] [end change] of the darker of the [begin change]foreground [LC-1182] [end change] or background colors.
Note 1: The relative luminance of an sRGB color is defined as 0.2126 * R + 0.7152 * G + 0.0722 * B where R, G and B are defined as:
[end change]if RsRGB <= 0.03928 then R = RsRGB/12.92 else R = ((RsRGB+0.055)/1.055) ^ 2.4
[end add]if GsRGB <= 0.03928 then G = GsRGB/12.92 else G = ((GsRGB+0.055)/1.055) ^ 2.4
[end add]if BsRGB <= 0.03928 then B = BsRGB/12.92 else B = ((BsRGB+0.055)/1.055) ^ 2.4
[end add]Note 2: Relative luminance values can range from 0 (black) to 1 (white), and contrast ratios can range from 1 to 21 (commonly written 1:1 to 21:1).
[end change]Note 3: For dithered colors, use average values of the colors used (average R, average G, and average B).
[end add]Note 4: Text can be evaluated with anti-aliasing turned off.
[end add]Note 5: For text displayed over gradients and background images, authors should ensure that sufficient contrast exists for each character in the content.
[end add]Note 6: [begin add]A MathML version of the contrast ratio definition is available. [LC-603] [LC-854] [end add]
the base font used for text in a paragraph
[end add]the width of the dominant stem of the font
[end add]Note: This is usually the width of the vertical stroke of the letter "T" in a Latin font (e.g. English).
serving only an aesthetic purpose, providing no information, and having no functionality.
The intent of this success criterion is to provide enough contrast between text and its background so that it can be easily read by people with low vision. The contrast is calculated in such a way that color is not a key factor so that people who also have a color vision deficit will also see a contrast between the text and the background. [begin add]Decorations that are included in an image along with a diagram but that convey no information are not part of the diagram. [LC-1161] [end add]
The 5:1 contrast ratio provides a minimum contrast of around 3:1 for the major types of color blindness. A contrast ratio of 3:1 is the minimum level recommended by [ISO-9241-3] and [ANSI-HFES-100-1988].
Calculations in ISO 9241-3 and ANSI/HFS 100-1988 are for body text. A relaxed contrast ratio is provided for text that is much larger (twice as tall and with three time the thickness of lines in the character).
Conversion from nonlinear to linear RGB values is based on IEC/4WD 61966-2-1 [IEC-4WD] and on "A Standard Default Color Space for the Internet - sRGB" [sRGB].
The formula (L1/L2) for contrast is based on ISO 9241-3 and ANSI/HFS 100-1988 standards.
The ANSI/HFS 100-1988 standard calls for the contribution from ambient light to be included in the calculation of L1 and L2. The .05 value used is based on Typical Viewing Flare from IEC/4WD 61966-2-1 and the sRGB paper by M. Stokes et al.
This success criterion and its definitions uses the terms contrast ratio and relative luminance rather than luminance to reflect the fact that Web content does not emit light itself. The contrast ratio gives a measure of the relative luminance that would result when displayed. (Because it is a ratio, it is dimensionless.)
Note: [begin add]Refer to related resources for a list of tools that utilize the contrast ratio to analyze the contrast of Web content. [LC-603] [end add]
People with low vision often have difficulty reading text that does not contrast with its background. This can be exacerbated if the person has a color vision deficiency that lowers the contrast even further. Providing a minimum luminance contrast ratio between the text and its background can make the text more readable even if the person does not see the full range of colors. It also works for the rare individuals who see no color.
Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this criterion. The techniques listed only satisfy the success criterion if all of the WCAG 2.0 conformance requirements have been met.
The following are common mistakes that are considered failures of Success Criterion 1.4.2 by the WCAG Working Group.
Although not required for conformance, the following additional techniques should be considered in order to make content more accessible. Not all techniques can be used or would be effective in all situations.
Using a higher contrast value for text that is over a patterned background (future link)
Creating foreground and background contrast (future link)
Using a light pastel background rather than a white background behind black text (future link) [LC-840]
[end add]Using unicode text and style sheets instead of images of text (future link) [LC-511]
[end add]Using a higher contrast values for lines in diagrams (future link)
[end add]Resources are for information purposes only, no endorsement implied.
1.4.3 Visually rendered text can be resized without assistive technology up to 200 percent and down to 50 percent without loss of content or functionality. [LC-469] (Level 2)
a user agent that [begin add]both[end add]:
provides services beyond those offered by the host user agents to meet the requirements of users with disabilities. [begin change]Such[end change] services include alternative renderings (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)[begin add], and[end add] [LC-1178]
relies on services (such as retrieving Web content and parsing markup) provided by one or more other "host" user agents. Assistive technologies communicate data and messages with host user agents by using and monitoring APIs
Note 1: [begin add]In this definition, the host user agents are user agents in the general sense of the term. That is, any software that retrieves and renders Web content for users. The host user agent may provide important services to assistive technologies like retrieving Web content from program objects or parsing markup into identifiable bundles. [LC-732] [end add]
Note 2: [begin add]Host user agents may also provide services directly that meet the requirements of users with disabilities. [LC-732] [end add]
Note 3: This definition is based on User Agent Accessibility Guidelines 1.0 Glossary.
Example: Examples of assistive technologies that are important in the context of this document include the following:
screen magnifiers, [begin change]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 [LC-604] [end change] improve the visual readability of rendered text and images;
screen readers, which are used by people who are blind [begin change]to read textual information through synthesized speech or braille[end change];
text-to-speech software, which is used by some people with cognitive, language, and learning disabilities to convert text into synthetic speech;
[end add]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;
alternative pointing devices, which are used by people with certain physical disabilities to simulate mouse pointing and button activations.
Editorial Note: Drafts in Wiki as How to meet 1.4.5, to be discussed Feb. 1 2007.
1.4.4 Text and images of text[begin delete], and lines in diagrams[end delete] have a contrast ratio of at least 10:1 with their background. Text or images of text may have a contrast ratio of at least 7:1 where all of the following are true: [LC-511] (Level 3)
[end change]Text is at least twice the height of the body text; and
the text has a stem width of at least three times the stem width of the body text; and
the text is presented over a non-patterned background.
Note: This requirement does not apply to text or images of text that are pure decoration.
(L1 + 0.05) / (L2 + 0.05), where L1 is the [begin change]relative luminance [LC-580] [end change] of the lighter of the [begin change]foreground [LC-1182] [end change] or background colors, and L2 is the [begin change]relative luminance [LC-580] [end change] of the darker of the [begin change]foreground [LC-1182] [end change] or background colors.
Note 1: The relative luminance of an sRGB color is defined as 0.2126 * R + 0.7152 * G + 0.0722 * B where R, G and B are defined as:
[end change]if RsRGB <= 0.03928 then R = RsRGB/12.92 else R = ((RsRGB+0.055)/1.055) ^ 2.4
[end add]if GsRGB <= 0.03928 then G = GsRGB/12.92 else G = ((GsRGB+0.055)/1.055) ^ 2.4
[end add]if BsRGB <= 0.03928 then B = BsRGB/12.92 else B = ((BsRGB+0.055)/1.055) ^ 2.4
[end add]Note 2: Relative luminance values can range from 0 (black) to 1 (white), and contrast ratios can range from 1 to 21 (commonly written 1:1 to 21:1).
[end change]Note 3: For dithered colors, use average values of the colors used (average R, average G, and average B).
[end add]Note 4: Text can be evaluated with anti-aliasing turned off.
[end add]Note 5: For text displayed over gradients and background images, authors should ensure that sufficient contrast exists for each character in the content.
[end add]Note 6: [begin add]A MathML version of the contrast ratio definition is available. [LC-603] [LC-854] [end add]
the base font used for text in a paragraph
[end add]the width of the dominant stem of the font
[end add]Note: This is usually the width of the vertical stroke of the letter "T" in a Latin font (e.g. English).
serving only an aesthetic purpose, providing no information, and having no functionality.
The intent of this success criterion is to provide enough contrast between text and its background so that it can be easily read by people with low vision. The contrast is calculated in such a way that color is not a key factor so that people who also have a color vision deficit will also see a contrast between the text and the background. [begin add]Decorations that are included in an image along with a diagram but that convey no information are not part of the diagram. [LC-1161] [end add]
The 10:1 contrast ratio provides a minimum contrast of around 7:1 for the major types of color blindness. A contrast ratio of 7:1 is recommended by [ANSI-HFES-100-1988].
Calculations in ISO 9241-3 and ANSI/HFS 100-1988 are for body text. A relaxed contrast ratio is provided for text that is much larger (twice as tall and with three time the thickness of lines in the character).
Conversion from nonlinear to linear RGB values is based on IEC/4WD 61966-2-1 [IEC-4WD] and on "A Standard Default Color Space for the Internet - sRGB" [sRGB].
The formula (L1/L2) for contrast is based on ISO 9241-3 and ANSI/HFS 100-1988 standards.
The ANSI/HFS 100-1988 standard calls for the contribution from ambient light to be included in the calculation of L1 and L2. The .05 value used is based on Typical Viewing Flare from IEC/4WD 61966-2-1 and the sRGB paper by M. Stokes et al.
This success criterion and its definitions uses the terms contrast ratio and relative luminance rather than luminance to reflect the fact that Web content does not emit light itself. The contrast ratio gives a measure of the relative luminance that would result when displayed. (Because it is a ratio, it is dimensionless.)
Note: [begin add]Refer to related resources for a list of tools that utilize the contrast ratio to analyze the contrast of Web content. [LC-603] [end add]
People with low vision often have difficulty reading text that does not contrast with its background. This can be exacerbated if the person has a color vision deficiency that lowers the contrast even further. Providing a minimum luminance contrast ratio between the text and its background can make the text more readable even if the person does not see the full range of colors. It also works for the rare individuals who see no color.
Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this criterion. The techniques listed only satisfy the success criterion if all of the WCAG 2.0 conformance requirements have been met.
The following are common mistakes that are considered failures of Success Criterion 1.4.4 by the WCAG Working Group.
(No failures currently documented)
Although not required for conformance, the following additional techniques should be considered in order to make content more accessible. Not all techniques can be used or would be effective in all situations.
Using a higher contrast value for text that is over a patterned background (future link)
Using unicode text and style sheets instead of images of text (future link) [LC-511]
[end add]Using a light pastel background rather than a white background behind black text (future link) [LC-840]
[end add]Using a higher contrast values for lines in diagrams (future link)
[end add]Resources are for information purposes only, no endorsement implied.
1.4.5 Audio content does not contain background sounds, background sounds can be turned off, or background sounds are at least 20 decibels lower than the foreground [begin delete]audio[end delete] [begin add]speech[end add] content, with the exception of occasional sound effects. [LC-743] (Level 3)
The intent of this success criterion is to ensure that any non-speech sounds are low enough that a user who is hard of hearing can understand the speech. Individuals who are hard of hearing have difficulty separating speech from background sounds or other noise. [begin change]Background sound that meets this requirement will be approximately one quarter as loud as the foreground speech content. [LC-743] [end change]
The value of 20 dB was chosen based on Large area assistive listening systems (ALS): Review and recommendations [LAALS] and In-the-ear measurements of interference in hearing aids from digital wireless telephones [HEARING-AID-INT] [LC-1228]
[end add]People who are hard of hearing often have great difficulty separating speech from background sound.
Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this criterion. The techniques listed only satisfy the success criterion if all of the WCAG 2.0 conformance requirements have been met.
Not including audio content (future link)
The following are common mistakes that are considered failures of Success Criterion 1.4.5 by the WCAG Working Group.
(No failures currently documented)
Although not required for conformance, the following additional techniques should be considered in order to make content more accessible. Not all techniques can be used or would be effective in all situations.
Providing a way for users to adjust auditory levels of foreground and background sound independently. (future link)
Resources are for information purposes only, no endorsement implied.
1.4.6 Visually rendered text can be resized without assistive technology up to 200 percent and down to 50 percent without loss of content or functionality and in a way that does not require the user to scroll horizontally. [LC-469] (Level 3)
a user agent that [begin add]both[end add]:
provides services beyond those offered by the host user agents to meet the requirements of users with disabilities. [begin change]Such[end change] services include alternative renderings (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)[begin add], and[end add] [LC-1178]
relies on services (such as retrieving Web content and parsing markup) provided by one or more other "host" user agents. Assistive technologies communicate data and messages with host user agents by using and monitoring APIs
Note 1: [begin add]In this definition, the host user agents are user agents in the general sense of the term. That is, any software that retrieves and renders Web content for users. The host user agent may provide important services to assistive technologies like retrieving Web content from program objects or parsing markup into identifiable bundles. [LC-732] [end add]
Note 2: [begin add]Host user agents may also provide services directly that meet the requirements of users with disabilities. [LC-732] [end add]
Note 3: This definition is based on User Agent Accessibility Guidelines 1.0 Glossary.
Example: Examples of assistive technologies that are important in the context of this document include the following:
screen magnifiers, [begin change]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 [LC-604] [end change] improve the visual readability of rendered text and images;
screen readers, which are used by people who are blind [begin change]to read textual information through synthesized speech or braille[end change];
text-to-speech software, which is used by some people with cognitive, language, and learning disabilities to convert text into synthetic speech;
[end add]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;
alternative pointing devices, which are used by people with certain physical disabilities to simulate mouse pointing and button activations.
Editorial Note: Drafts in Wiki as How to meet 1.4.6, to be discussed Feb. 1 2007.
If all functionality can be achieved using the keyboard, it can be accomplished by keyboard users, by speech input (which creates keyboard input), by mouse (using on-screen keyboards), and by a wide variety of assistive technologies that create simulated keystrokes as their output. No other input form has this flexibility or is universally supported and operable by people with different disabilities, as long as the keyboard input is not time-dependent.
Note that providing universal keyboard input does not mean that other types of input should not be supported. Optimized speech input, optimized mouse/pointer input, etc., are also good. The key is to provide keyboard input and control as well.
Some devices do not have native keyboards—for example, a PDA or cell phone. If these devices have a Web browsing capability, however, they will have some means of generating text or "keystrokes." This guideline uses the term "keyboard interface" to acknowledge that Web content should be controlled from keystrokes that may come from a keyboard, keyboard emulator, or other hardware or software that generates keyboard or text input.
Specific techniques for meeting each success criterion for this guideline are listed in the How to Meet sections for each success criterion (listed below). If there are techniques, however, for addressing this guideline that do not fall under any of the success criteria, they are listed here. These techniques are not required or sufficient for meeting any success criteria, but can make certain types of Web content more accessible to more people.
2.1.1 All functionality of the content is operable [begin change]through a keyboard interface without requiring specific timings for individual keystrokes, except where the [begin add]underlying[end add] task requires time-dependent analog input. [end change] [LC-922] [LC-1164] (Level 1)
Note: This does not forbid and should not discourage providing mouse input or other input methods in addition to keyboard operation.
[end change]processes and outcomes achievable through user action
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.
input whose result is different depending on the rate of the analog movement (such as when line width varies with pen speed or pressure)
Note: Most actions carried out by a pointing device can also be done from the keyboard (for example, clicking, selecting, moving, sizing). However, there is a small class of input that is done with a pointing device that cannot be done from the keyboard in any known fashion. This type of input can be best characterized by the fact that the outcome can only be achieved by moving the pointer in a smooth fashion at a certain rate. For example, in a watercolor program stroke width and transparency may depend on the rate of movement (and/or pressure) of a "brush." [begin add]Another example would be a real-time helicopter flight simulator. [LC-1164] [end add]
The intent of this success criterion is to ensure that, wherever possible, content can be operated through a keyboard or keyboard interface. When content can be operated through a keyboard or alternate keyboard, it is operable by people with no vision (who cannot use devices such as mice that require eye-hand coordination) as well as by people who must use alternate keyboards or input devices that act as keyboard emulators. Keyboard emulators include speech input software, sip-and-puff software, on-screen keyboards, scanning software and a variety of assistive technologies and alternate keyboards. Individuals with low vision also may have trouble tracking a pointer and find the use of software much easier (or only possible) if they can control it from the keyboard.
Examples of "specific timings for individual keystrokes" include situations where a user would be required to repeat or execute multiple keystrokes within a short period of time or where a key must be held down for an extended period before the keystroke is registered. [LC-1164]
[end add]The phrase "except where the task requires analog, time-dependent input" is included to separate those things that cannot reasonably be controlled from a keyboard. For example, a watercolor application where the stroke is defined by the movement and speed of movement and/or pressure is not something that can be controlled from a keyboard. Also, the use of MouseKeys would not satisfy this success criterion because it is not a keyboard equivalent to the application; it is a mouse equivalent (i.e. it looks like a mouse to the application).
Note: This time dependence is not a [begin change]time limit[end change] situation, so is not covered by 2.2.1.
When considering whether analog, time-dependent input is required for the underlying task (what you are trying to do) a key question is, could you achieve the same functionality in a different way using an input device that was not analog, time-dependent (e.g. using a keyboard). [LC-922]
[end add]People who are blind (who cannot use devices such as mice that require eye-hand coordination)
People with low vision (who may have trouble finding or tracking a pointer indicator on screen)
[begin add]Some people with hand tremors find using a mouse very difficult and therefore usually use a keyboard [LC-1086] [end add]
Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this criterion. The techniques listed only satisfy the success criterion if all of the WCAG 2.0 conformance requirements have been met.
G21: Ensuring that users are not trapped in content AND G90: Providing keyboard-controllable event handlers USING one of the following techniques:
SCR20: Using both keyboard and other device-specific functions (SCRIPT)
Making JavaScript actions keyboard accessible (future link)
Creating device-independent image effects (future link)
The following are common mistakes that are considered failures of Success Criterion 2.1.1 by the WCAG Working Group.
F55: Failure of SC 2.1.1 and 3.2.1 due to using script to remove focus when focus is received
Failure due to causing automatic page refresh to occur without providing a way to deactivate or control the time limit (future link) [LC-1048]
[end add]Although not required for conformance, the following additional techniques should be considered in order to make content more accessible. Not all techniques can be used or would be effective in all situations.
Providing keyboard access to important links and form controls (future link)
Using unique letter combinations to begin each item of a list (future link)
Choosing the most abstract event handler (future link)
Using the onactivate event (future link)
Avoiding use of common user-agent keyboard commands for other purposes (future link) [LC-726]
[end add]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.
2.1.2 All functionality of the content is operable in a non-time-dependent manner through a keyboard interface. (Level 3)
processes and outcomes achievable through user action
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.
The intent of this success criterion is to ensure that all content is operable from the keyboard.This is the same as success criterion 2.1.1, except that no exceptions are allowed. This does not mean that analog, time-dependent input (excluded from the requirements of 2.1.1) must be made keyboard accessible. Rather, it means that content that uses analog, time-dependent input cannot conform to this success criterion and therefore cannot meet Guideline 2.1 at Level 3.
Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this criterion. The techniques listed only satisfy the success criterion if all of the WCAG 2.0 conformance requirements have been met.
No additional techniques exist for this Success Criterion. Follow techniques for Success Criterion 2.1.1. If that is not possible because there is a requirement for analog, time-dependent input, then it is not possible to meet this Level 3 Success Criterion.
Many users who have disabilities need more time to complete tasks than the majority of users: they may take longer to physically respond, they may take longer to read things, they may have low vision and take longer to find things or to read them, or they may be accessing content through an assistive technology that requires more time. This guideline focuses on ensuring that users are able to complete the tasks required by the content with their own individual response times. The primary approaches deal with eliminating time constraints or providing users enough additional time to allow them to complete their tasks. Exceptions are provided for those cases where this is not possible.
Specific techniques for meeting each success criterion for this guideline are listed in the How to Meet sections for each success criterion (listed below). If there are techniques, however, for addressing this guideline that do not fall under any of the success criteria, they are listed here. These techniques are not required or sufficient for meeting any success criteria, but can make certain types of Web content more accessible to more people.
2.2.1 For each [begin change]time limit[end change] that is [begin delete]a function of the content[end delete] [begin add]set by the content [LC-1166] [end add], at least one of the following is true: [LC-996] (Level 1)
Deactivate: the user is allowed to deactivate the [begin change]time limit[end change] [begin add]before encountering it [LC-1238] [end add]; or
Adjust: the user is allowed to adjust the [begin change]time limit[end change] [begin add]before encountering it [LC-1238] [end add] 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 [begin change]time limit[end change] with a simple action (for example, "hit any key"), and the user is allowed to extend the [begin change]time limit[end change] at least ten times; or
Real-time Exception: the [begin change]time limit[end change] is a[begin delete]n important[end delete] [begin add]required [LC-1046] [end add] part of a real-time event (for example, an auction), and no alternative to the [begin change]time limit[end change] is possible; or
Essential Exception: the [begin change]time limit[end change] is part of an activity where timing is essential (for example, competitive gaming or time-based testing) and time limits can not be extended further without invalidating the activity.
activity where timing is part of the design of the activity and removal of the time dependency would change the functionality of the content
The intent of this success criterion is to ensure that users with disabilities are given adequate time to interact with Web content whenever possible. People with disabilities such as blindness, dexterity impairments, and cognitive limitations may require more time to perform functions such as filling out on-line forms. If Web functions are time-dependent, it will be difficult for some users to perform the required action before a [begin change]time limit[end change] occurs. This may render the service inaccessible to them. Designing functions that are not time-dependent will help people with disabilities succeed at completing these functions. Providing options to disable time limits, customize the length of [begin change]time limits[end change], or request more time before a [begin change]time limit[end change] occurs helps those users who require more time than expected to successfully complete tasks. [begin add]Any process that happens without user initiation after a set time or on a periodic basis is a [begin change]time limit[end change]. This includes partial or full updates of content, changes to content, or the expiration of a window of opportunity for a user to react to a request for input. [LC-1089] [end add]
In some cases, however, it is not possible to change the [begin change]time limit[end change] (for example, for an auction or other real-time event) and exceptions are therefore provided for those cases.
Notes regarding server time limits
Timed server redirects can be found below under Common Failures.
Server [begin change]time limits[end change] like login expiration are dealt with in success criterion 2.2.6.
Non-timed server redirects (e.g. 3xx response codes) are not applicable because there is no [begin change]time limit[end change]: they work instantly.
[begin add]This Success Criterion applies only to time limits that are set by the content itself. Time limits set externally to content, such as by the user agent or by factors intrinsic to the Internet, are not under the author's control and not subject to WCAG conformance requirements. Time limits set by Web servers should be under the author's control and are addressed by other SC. [LC-1166] [end add]
10 times the default was chosen based on clinical experience and other guidelines. For example, if 15 seconds is allowed for a user to respond and hit a switch, 150 seconds would be sufficient to allow almost all users to hit a switch even if they had trouble. [LC-1230]
[end add]20 seconds was also based on clinical experience and other guidelines. 20 seconds to hit 'any switch' is sufficient for almost all users including those with spasticity. Some would fail, but some would fail all lengths of time. A reasonable period for requesting more time is required since an arbitrarily long time can provide security risks to all users, including those with disabilities, for some applications. For example, with kiosks or terminals that are used for financial transactions, it is quite common for people to walk away without signing off. This leaves them vulnerable to those walking up behind them. Providing a long period of inactivity before asking, and then providing a long period for the person to indicate that they are present can leave terminals open for abuse. If there is no activity the system should ask if the user is there. It should then ask for an indication that a person is there ('hit any key') and then wait long enough for almost anyone to respond. For "hit any key," 20 seconds would meet this. If the person indicates that they are still present, the device should return the user to the exact condition that existed before it asked the question. [LC-1230]
People with physical disabilities often need more time to react, to type and to complete activities. People with low vision need more time to locate things on screen and to read. People who are blind and using screen readers may need more time to understand screen layouts, to find information and to operate controls. People who have cognitive or language limitations need more time to read and to understand. People who are deaf and communicate in sign language may need more time to read information printed in text (which may be a second language for some).
In circumstances where a sign-language interpreter may be relating audio content to a user who is deaf, control over time limits is also important.
Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this criterion. The techniques listed only satisfy the success criterion if all of the WCAG 2.0 conformance requirements have been met.
Instructions: Select the situation below that matches your content. Each situation includes techniques or combinations of techniques that are known and documented to be sufficient for that situation.
Providing a way for the user to turn the [begin change]time limit[end change] off (future link)
Providing the user with a means to set the [begin change]time limit[end change] to 10 times the default [begin change]time limit[end change] (future link)
SCR16: Providing a script that warns the user a time limit is about to expire (SCRIPT) AND SCR1: Allowing the user to extend the default time limit (SCRIPT)
The following are common mistakes that are considered failures of Success Criterion 2.2.1 by the WCAG Working Group.
Although not required for conformance, the following additional techniques should be considered in order to make content more accessible. Not all techniques can be used or would be effective in all situations.
Using a script to poll the server and notify a user if a [begin change]time limit[end change] is present (future link)
A Web site uses a client side [begin change]time limit[end change] to help protect consumers who may step away from their computer. After a period of inactivity the Web page asks if the user needs more time. If it doesn’t get a response – it times out.
A Web page has a field that automatically updates with the latest headlines in a rotating fashion. There is an interactive control that allows the user to extend the length of time between each update to as much as 10 times the default. The control can be operated with either a mouse or a keyboard. [LC-783]
[end change]In an auction, there is a time limit on the amount of time a user has to submit a bid. Since the time limit applies to all users who want to bid on a particular item, it would be unfair to extend the time limit for any one particular user. Therefore, a time limit is required for this type of activity and no extension, adjustment, or deactivation of the time limit is required by this success criteria. [LC-1046]
[end change]An online ticket-purchasing site gives the user two minutes to confirm a purchase before the seats are returned to the general pool. Because tickets on such sites can sell out quickly, holding a ticket longer than that may invalidate the nature of the site, so this is a case in which the timing is essential and cannot be extended without invalidating the activity. However, the site does move as much of the process out of the time-critical period as possible, for instance allowing users to provide necessary information like name, payment method, etc., before entering the time-critical stage. [LC-1167]
[end add]A ticket-purchasing site allows the user two minutes to confirm purchase of selected seats, but warns the user when their time is almost out and allows the user to extend this time limit some number of times with a simple action such as clicking a "Extend time limit" button. [LC-1167]
[end add]Resources are for information purposes only, no endorsement implied.
(none currently documented)
2.2.2 Content does not blink for more than three seconds, or a method is available to stop all blinking content in the Web page [begin delete] or authored component[end delete] [LC-745] . (Level 2)
Note: For requirements related to flickering or flashing content, refer to Allow users to avoid content that could cause seizures due to photosensitivity: .
turn on and off between 0.5 and 3 times per second
Note: The slower blink is in contrast with flashing, which refers to rapid changes in brightness which can cause seizures. See general flash threshold and red flash threshold. [LC-1414]
a resource that is referenced by a URI and is not embedded in another resource, plus any other resources that are used in the rendering or intended to be rendered together with it [LC-862]
[end change]Note: Although any "other resources" would be rendered together with the primary resource, they would not necessarily be rendered simultaneously with each other.
Example 1: A movie-like interactive shopping environment where the user visually moves about a store dragging products off of the shelves around them into a visual shopping cart in front of them. Clicking on a product causes it to be demonstrated with a specification sheet alongside.
Example 2: A Web resource including all embedded images and media.
The intent of this success criterion is to avoid distracting users during their interaction with a Web page. Certain groups, particularly those with attention deficit disorders, find blinking content distracting, making it difficult for them to concentrate on other parts of the Web page. Three seconds was chosen because it is long enough to get a user's attention, but not so long that a user can not wait it out if necessary in order to use the page and the blinking blocks their ability to focus on the page.
Providing content that stops blinking after three seconds or providing a mechanism for users to stop blinking content allows people with certain disabilities to interact with the Web page.
One use of content that blinks is to draw the visitor's attention to that content. Although this is an effective technique for all users with vision, it can be a problem for some users if it persists. For certain groups, including people with low literacy, reading and intellectual disabilities, and people with attention deficit disorders, content that blinks may make it difficult or even impossible to interact with the rest of the Web page.
Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this criterion. The techniques listed only satisfy the success criterion if all of the WCAG 2.0 conformance requirements have been met.
Using a technology to include blinking content that can be turned off via the user agent (future link)
Using a control in the Web page that stops blinking content (future link) USING one of the following techniques:
Setting animated gif images to stop blinking after n cycles (within 3 seconds) (future link)
Providing a link, button, or other mechanism that reloads the page without the blinking content (future link) [LC-1168]
SCR22: Using scripts to control blinking and stop it in three seconds or less (SCRIPT)
The following are common mistakes that are considered failures of Success Criterion 2.2.2 by the WCAG Working Group.
Although not required for conformance, the following additional techniques should be considered in order to make content more accessible. Not all techniques can be used or would be effective in all situations.
Providing a mechanism to stop all content that blinks within a Web page (future link)
Providing the user with a means to stop moving content even if it stops automatically within 3 seconds (future link)
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.
Resources are for information purposes only, no endorsement implied.
(none currently documented)
2.2.3 [begin add]Moving, blinking, scrolling, or auto-updating information can be paused by the user unless it is part of an activity where timing or movement is essential. Moving content that is pure decoration can be stopped by the user.[end add] [begin delete]Content can be paused by the user unless the timing or movement is part of an activity where timing or movement is essential.[end delete] [LC-1169] (Level 2)
stopped by user request and not restarted until requested by user
activity where timing is part of the design of the activity and removal of the time dependency would change the functionality of the content
stopped by user request and not restarted until requested by user
activity where timing is part of the design of the activity and removal of the time dependency would change the functionality of the content
The intent of this success criterion is to provide an option to temporarily stop content from advancing or updating at a rate beyond the user's ability to read and/or understand the content as it changes.
"Moving" refers to content in which the visible content conveys a sense of motion. Common examples include motion pictures, multimedia presentations, animations, real-time games, and scrolling stock tickers.
"Time-based" refers to content that updates or disappears based on a preset time interval. Common time-based content includes audio, automatically updated weather information, news, stock price updates, and auto-advancing presentations and messages.
People with reading disabilities, cognitive limitations, and learning disabilities who may need more time to read or comprehend information can have additional time to read the information by pausing the content.
In circumstances where a sign-language interpreter may be relating audio content to a user who is deaf, control over time limits is also important.
Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this criterion. The techniques listed only satisfy the success criterion if all of the WCAG 2.0 conformance requirements have been met.
G4: Allowing the content to be paused and restarted from where it was stopped
Using script to scroll content, and providing a mechanism to pause it (future link)
The following are common mistakes that are considered failures of Success Criterion 2.2.3 by the WCAG Working Group.
Although not required for conformance, the following additional techniques should be considered in order to make content more accessible. Not all techniques can be used or would be effective in all situations.
(none currently documented)
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.
[begin change]A stock ticker has "pause" and "restart" buttons. Pausing the ticker causes it to pause on the currently displayed stock. Restarting causes the ticker to resume from the stopped point but with a notice that the display is delayed. Since the intent of the stock ticker is usually to provide realtime information, there might also be a button that would advance the ticker to the most recently traded stock. [LC-772] [end change]
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.
An auction.
Users cannot pause the timing of an auction because of the nature of the activity. Instead, the user is allowed to prepare a bid and hold it - so that a single keystroke submits it.
Resources are for information purposes only, no endorsement implied.
(none currently documented)
2.2.4 Timing is not an essential part of the event or activity presented by the content, except for [begin add]non-interactive multimedia and[end add] real-time events [begin delete]Except for non-interactive multimedia and real-time events, timing is not an essential part of the event or activity presented by the content[end delete]. [LC-1305] (Level 3)
[end change]audio or video synchronized with another [begin delete]type of media[end delete] [begin add]format for presenting information[end add] and/or with time-based interactive components [LC-1499]
event that a) occurs at the same time as the viewing, b) is not completely generated by the content, and c) is not pre-recorded
Example 1: A Webcast of a live performance [begin add](occurs at the same time as the viewing and is not pre-recorded)[end add].
Example 2: An on-line auction with people bidding [begin add](occurs at the same time as the viewing)[end add].
Example 3: Live humans interacting in a fantasy world using avatars [begin add](is not completely generated by the content and occurs at the same time as the viewing)[end add] [LC-1503] .
The intent of this success criterion is to minimize the occurrence of content that requires timed interaction. This enables people with blindness, low vision, cognitive limitations, or motor impairments to interact with content. This differs from the Level 1 success criterion in that the only exception is for real-time events.
Note: Video only, such as sign language, is covered in Guideline 1.1. [LC-1305]
People with physical disabilities often need more time to react, to type and to complete activities. People with low vision need more time to locate things on screen and to read. People who are blind and using screen readers may need more time to understand screen layouts, to find information and to operate controls. People who have cognitive or language limitations need more time to read and to understand. People who are deaf and communicate in sign language may need more time to read information printed in text (which may be a second language for some).
In circumstances where a sign-language interpreter may be relating audio content to a user who is deaf, control over time limits is also important.
Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this criterion. The techniques listed only satisfy the success criterion if all of the WCAG 2.0 conformance requirements have been met.
The following are common mistakes that are considered failures of Success Criterion 2.2.4 by the WCAG Working Group.
(No failures currently documented)
Although not required for conformance, the following additional techniques should be considered in order to make content more accessible. Not all techniques can be used or would be effective in all situations.
(none currently documented)
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.
Resources are for information purposes only, no endorsement implied.
(none currently documented)
2.2.5 Interruptions, such as updated content, can be postponed or suppressed by the user, except interruptions involving an emergency. (Level 3)
a sudden, unexpected situation or occurrence that requires immediate action to preserve health, safety, or property
The intent of this success criterion is to allow users to turn off updates from the author/server except in emergencies. Emergencies would include civil emergency alert messages or any other messages that warn of danger to health, safety, or property, including data loss, loss of connection, etcetera.
This allows access by people with cognitive limitations or attention disorders to be able to focus on the content. It also allows users who are blind or have low vision to keep their "viewing" focus on the content they are currently reading.
Individuals with attention deficit disorders can focus on content without distraction.
Individuals with low vision or who use screen readers will not have content updated while they are viewing it (which can lead to discontinuity and misunderstanding if they start reading in one topic and finish in another).
Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this criterion. The techniques listed only satisfy the success criterion if all of the WCAG 2.0 conformance requirements have been met.
G75: Providing a mechanism to postpone any updating of content
Allowing users to request updates instead of automatically updating content (future link)
SCR14: Using scripts to make nonessential alerts optional (SCRIPT)
The following are common mistakes that are considered failures of Success Criterion 2.2.5 by the WCAG Working Group.
Although not required for conformance, the following additional techniques should be considered in order to make content more accessible. Not all techniques can be used or would be effective in all situations.
(none currently documented)
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.
Resources are for information purposes only, no endorsement implied.
(none currently documented)
2.2.6 When an authenticated session expires, the user can continue the activity without loss of data after re-authenticating. (Level 3)
The intent of this success criterion is to allow all users to complete authenticated transactions that have inactivity [begin change]time limit[end change]s. For security reasons, many sites implement an authentication [begin change]time limit[end change] after a certain period of inactivity. These [begin change]time limits[end change] may cause problems for persons with disabilities because it may take longer for them to complete the activity. These users must be given the ability to re-authenticate and continue with the transaction without the loss of any data already entered.
This success criterion benefits people who may require additional time to complete an activity. People with cognitive limitations may read slowly and require additional time to read and respond to a questionnaire. Users interacting via a screen reader may need extra time to navigate and complete a complicated form. A person with motor impairments or who navigates with an alternative input device may require additional time to navigate through or complete input within a form.
In circumstances where a sign-language interpreter may be relating audio content to a user who is deaf, control over time limits is also important.
Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this criterion. The techniques listed only satisfy the success criterion if all of the WCAG 2.0 conformance requirements have been met.
Providing options to continue without loss of data using one of the following technqiues:
G105: Saving data so that it can be used after a user re-authenticates
Encoding user data as hidden data in re-authorization page (future link)
Note: Refer to Techniques for Addressing Success Criterion 2.2.1 for techniques related to providing notifications about time limits. [LC-1097]
The following are common mistakes that are considered failures of Success Criterion 2.2.6 by the WCAG Working Group.
Although not required for conformance, the following additional techniques should be considered in order to make content more accessible. Not all techniques can be used or would be effective in all situations.
(none currently documented)
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 [begin change]time limit[end change] occurs wile the user is performing the checkout process. When the user returns to the checkout process and submits the form, the site returns a login screen to re-authenticate. After the user logs in, the check out process is restored with the same information and at the same stage. The user did not lose any data because the server had temporarily accepted and stored the submission even though the session had timed out and restored the user to the same state after re-authentication was completed.
Authentication in an email program
An email program has an authentication time-out after 30 minutes. The program prompts the user several minutes before the time-out occurs and provides a link to open a new window in order to re-authenticate. The original window with the in-progress email remains intact and, after re-authentication, the user may send that data.
A questionnaire with a [begin change]time limit[end change]
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 [begin change]in the list of accessibility-supported content technologies that are relied on[end change], the user can elect to be alerted via a pop-up if the session is close to timing out.
Resources are for information purposes only, no endorsement implied.
(none currently documented)
Some people with seizure disorders can have a seizure triggered by flashing visual content. Most people are unaware that they have this disorder until it strikes. In 1997, a cartoon on television in Japan sent over 700 children to the hospital, including about 500 who had seizures [EPFND]. Warnings do not work well because they are often missed, especially by children who may in fact not be able to read them.
The objective of this guideline is to ensure that content that is marked as conformant to WCAG 2.0 avoids the types of flash that are most likely to cause seizure when viewed even for a second or two.
Specific techniques for meeting each success criterion for this guideline are listed in the How to Meet sections for each success criterion (listed below). If there are techniques, however, for addressing this guideline that do not fall under any of the success criteria, they are listed here. These techniques are not required or sufficient for meeting any success criteria, but can make certain types of Web content more accessible to more people.
Ensuring that content does not violate spatial pattern thresholds (future link)
2.3.1 Content does [begin add]contain anything that flashes more than three times in any one second period, or the flash is below the general flash threshold and the red flash threshold [LC-1187] [end add] [begin delete]violate the general flash threshold or the red flash threshold [end delete]. (Level 1)
[end change]A sequence of flashes or rapidly changing image sequences where all [begin change]four[end change] of the following occur:
[end change]there are more than three flashes within any one-second period; and
the flashing is below 50 Hz; and
the brightness of the darker image is below .80 of full scale white brightness; and
[end add]the combined area of flashes occurring concurrently [begin add]and contiguously[end add] [begin delete](but not necessarily contiguously)[end delete] occupies more than [begin add]a total of .006 steradians (or one quarter of any 10 degree visual field on the screen ).[end add] [begin delete]341 x 256 pixel rectangle anywhere on the displayed screen area when the content is viewed at 1024 x 768 pixels;[end delete]
Note 1: For the general flash threshold, a flash is defined as a pair of opposing changes in brightness of 10% or more of full scale white brightness.
Note 2: Brightness is calculated as 0.2126 * ((R / FS) ^ 2.2) + 0.7152 * ((G / FS) ^ 2.2) + 0.0722 * ((B / FS) ^ 2.2). R, G, and B are the red, green, and blue RGB values of the color; FS is the maximum possible full scale RGB value for R, G, and B (255 for eight bit color channels); and the "^" character is the exponentiation operator.
Note 3: An "opposing change" is an increase followed by a decrease, or a decrease followed by an increase.[begin delete]This applies only when the brightness of the darker image is below .80 of full scale white brightness.[end delete]
Note 4: For general 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 of standard screen sizes and viewing distances.
[end add]Note 5: Based on Wisconsin Computer Equivalence Algorithm for Flash Pattern Analysis (FPA)
[end delete][LC-1187]
transition to or from a saturated red where all three of the following occur:
there are more than three flashes within any one-second period; and
the flashing is below 50 Hz; and
[begin add]the combined area of flashing occurring concurrently and contiguously occupies more than a total of .006 steradians (or one quarter of any 10 degree visual field on the screen).[end add] [begin delete]the combined area of flashes occurring concurrently occupies more than one quarter of any 341 x 256 pixel rectangle anywhere on the displayed screen area when the content is viewed at 1024 x 768 pixels.[end delete]
Note: For general 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 of standard screen sizes and viewing distances.
A sequence of flashes or rapidly changing image sequences where all [begin change]four[end change] of the following occur:
[end change]there are more than three flashes within any one-second period; and
the flashing is below 50 Hz; and
the brightness of the darker image is below .80 of full scale white brightness; and
[end add]the combined area of flashes occurring concurrently [begin add]and contiguously[end add] [begin delete](but not necessarily contiguously)[end delete] occupies more than [begin add]a total of .006 steradians (or one quarter of any 10 degree visual field on the screen ).[end add] [begin delete]341 x 256 pixel rectangle anywhere on the displayed screen area when the content is viewed at 1024 x 768 pixels;[end delete]
Note 1: For the general flash threshold, a flash is defined as a pair of opposing changes in brightness of 10% or more of full scale white brightness.
Note 2: Brightness is calculated as 0.2126 * ((R / FS) ^ 2.2) + 0.7152 * ((G / FS) ^ 2.2) + 0.0722 * ((B / FS) ^ 2.2). R, G, and B are the red, green, and blue RGB values of the color; FS is the maximum possible full scale RGB value for R, G, and B (255 for eight bit color channels); and the "^" character is the exponentiation operator.
Note 3: An "opposing change" is an increase followed by a decrease, or a decrease followed by an increase.[begin delete]This applies only when the brightness of the darker image is below .80 of full scale white brightness.[end delete]
Note 4: For general 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 of standard screen sizes and viewing distances.
[end add]Note 5: Based on Wisconsin Computer Equivalence Algorithm for Flash Pattern Analysis (FPA)
[end delete][LC-1187]
transition to or from a saturated red where all three of the following occur:
there are more than three flashes within any one-second period; and
the flashing is below 50 Hz; and
[begin add]the combined area of flashing occurring concurrently and contiguously occupies more than a total of .006 steradians (or one quarter of any 10 degree visual field on the screen).[end add] [begin delete]the combined area of flashes occurring concurrently occupies more than one quarter of any 341 x 256 pixel rectangle anywhere on the displayed screen area when the content is viewed at 1024 x 768 pixels.[end delete]
Note: For general 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 of standard screen sizes and viewing distances.
The intent of this success criterion is to allow users to access the full content of a site without inducing seizures due to photosensitivity.
Individuals who have photosensitive seizure disorders can have a seizure triggered by content that flashes at certain frequencies for more than a few flashes. People are even more sensitive to red flashing than to other colors, so a special test is provided for saturated red flashing. These guidelines are based on guidelines for the broadcasting industry as adapted for computer screens, where content is viewed from a closer distance (using a larger angle of vision).
Flashing can be caused by the display, the computer rendering the image or by the content being rendered. The author has no control of the first two. They can be addressed by the design and speed of the display and computer. The intent of this criterion is to ensure that flicker that violates the flash thresholds is not caused by the content itself. For example, the content could contain a video clip or animated image of a series of strobe flashes, or close-ups of rapid-fire explosions. [LC-1414]
[end add]This success criterion replaces a much more restrictive criterion in WCAG 1.0 that did not allow any flashing (even of a single pixel) within a broad frequency range (3 to 50 Hz). This success criterion is based on existing specifications in use in England and by others for television broadcast and has been adapted for computer display viewing. The 1024 x 768 screen is used as the reference screen resolution for the evaluation. The 341 x 256 pixel block represents a 10 degree viewport at a typical viewing distance. (The 10 degree field is taken from the original specifications and represents the central vision portion of the eye, where people are most susceptible to photo stimuli.)
The combined area of flashes occurring concurrently (but not necessarily contiguously) means the total area that is actually flashing at the same time. It is calculated by adding up all of the areas of the individual flashes within any 341 x 256 pixel viewport that are occurring at the same time.
Individuals who have seizures when viewing flashing material will be able to view all of the material on a site without having a seizure and without having to miss the full experience of the content by being limited to text alternatives. This includes people with photosensitive epilepsy as well as other photosensitive seizure disorders.
Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this criterion. The techniques listed only satisfy the success criterion if all of the WCAG 2.0 conformance requirements have been met.
The following are common mistakes that are considered failures of Success Criterion 2.3.1 by the WCAG Working Group.
(No failures currently documented)
Although not required for conformance, the following additional techniques should be considered in order to make content more accessible. Not all techniques can be used or would be effective in all situations.
Reducing contrast for any flashing content (future link)
Avoiding fully saturated reds for any flashing content (future link)
Reducing the number of flashes even if they do not violate thresholds (future link)
Providing a mechanism to suppress any flashing content before it begins (future link) [LC-1099]
[begin add]A Web site has video of muzzle flash of machine gun fire, but limits the size of the flashing image to a small portion of the screen below the flash threshold size. [LC-1101] [end add]
A movie with a scene involving very bright lightning flashes is [begin change]edited[end change] so that the lightning only flashes three times in any one second period. [LC-785] [LC-1101]
Resources are for information purposes only, no endorsement implied.
2.3.2 [begin change]Content does not contain anything that flashes more than three times in any one second period. [end change] [LC-494] (Level 3)
The intent of this success criterion is to allow users to access the full content of a site without inducing seizures due to photosensitivity.
Success criterion 2.3.1 requires that flashing content be less than three flashes in any 1-second period unless it is smaller than 40% of a 341 x 256 pixel area (on a 1024 x 768 screen). This would keep the stimuli to less than 40% of a person's central vision for a typical screen. However, some users access Web content through screen enlargers. For these people, the area described in section 2.3.1 would (when magnified) be more than 40% of a persons central vision.
This success criterion eliminates all flashing components that flash more than three times in any 1-second period. In this fashion, magnification at any level would not yield content that would fail the general flash or red flash thresholds.
Individuals who have seizures when viewing flashing material will be able to view all of the material on a site without having a seizure and without having to miss the full experience of the content by being limited to text alternatives. This includes people with photosensitive epilepsy as well as other photosensitive seizure disorders.
Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this criterion. The techniques listed only satisfy the success criterion if all of the WCAG 2.0 conformance requirements have been met.
The following are common mistakes that are considered failures of Success Criterion 2.3.2 by the WCAG Working Group.
(No failures currently documented)
Although not required for conformance, the following additional techniques should be considered in order to make content more accessible. Not all techniques can be used or would be effective in all situations.
Reducing contrast for any flashing content (future link)
Avoiding fully saturated reds for any flashing content (future link)
Reducing the number of flashes even if they don't violate thresholds (future link)
A movie with a scene involving very bright lightning flashes is [begin change]edited[end change] so that the lightning only flashes three times in any one second period. [LC-785]
Resources are for information purposes only, no endorsement implied.
The intent of this guideline is to help users find the content they need and allow them to keep track of their location. These tasks are often more difficult for people with disabilities. For finding, navigation, and orientation, it is important that the user can find out what the current location is. For navigation, information about the possible destinations needs to be available. Screen readers convert content to synthetic speech which, because it is audio, must be presented in linear order. Some success criteria in this guideline explain what provisions need to be taken to ensure that screen reader users can successfully navigate the content. Others allow users to more easily recognize navigation bars and page headers and to bypass this repeated content. [begin add]Unusual user interface features or behaviors may confuse people with cognitive disabilities. [LC-946] [end add]
This guideline works closely with Guideline 1.3, which ensures that any structure in the content can be perceived, a key to navigation as well. [begin add]Headings are particularly important mechanisms for helping users orient themselves within content and navigate through it. Many users of assistive technologies rely on appropriate headings to skim through information and easily locate the different sections of content. Satisfying Success Criterion 1.3.1 for headings also addresses some aspects of Guideline 2.4.[end add] [LC-562]
Specific techniques for meeting each success criterion for this guideline are listed in the How to Meet sections for each success criterion (listed below). If there are techniques, however, for addressing this guideline that do not fall under any of the success criteria, they are listed here. These techniques are not required or sufficient for meeting any success criteria, but can make certain types of Web content more accessible to more people.
Limiting the number of links per page (future link)
[begin add]Providing mechanisms to navigate to different sections of the content of a Web page (future link) [LC-928] [end add]
2.4.1 A mechanism is available to bypass blocks of content that are repeated on multiple Web pages. (Level 1)
a resource that is referenced by a URI and is not embedded in another resource, plus any other resources that are used in the rendering or intended to be rendered together with it [LC-862]
[end change]Note: Although any "other resources" would be rendered together with the primary resource, they would not necessarily be rendered simultaneously with each other.
Example 1: A movie-like interactive shopping environment where the user visually moves about a store dragging products off of the shelves around them into a visual shopping cart in front of them. Clicking on a product causes it to be demonstrated with a specification sheet alongside.
Example 2: A Web resource including all embedded images and media.
The intent of this success criterion is to allow people who navigate sequentially through content more direct access to the primary content of the Web page. Web pages and applications often have content that appears on other pages or screens. Examples of repeated blocks of content include but are not limited to navigation links, heading graphics, and advertising frames.
This is in contrast to a sighted user's ability to ignore the repeated material either by focusing on the center of the screen (where main content usually appears) or a mouse user's ability to select a link with a single mouse click rather than encountering every link or form control that comes before the item they want.
When this success criterion is not satisfied, it may be difficult for people with some disabilities to reach the main content of a Web page quickly and easily.
Screen reader users who visit several pages on the same site can avoid having to hear all heading graphics and dozens of navigation links on every page before the main content is spoken.
People who use only the keyboard or a keyboard interface can reach content with fewer keystrokes. Otherwise, they might have to make dozens of keystrokes before reaching a link in the main content area. This can take a long time and may cause severe physical pain for some users.
People who use screen magnifiers do not have to search through the same headings or other blocks of information to find where the content begins each time they enter a new page.
People with cognitive limitations as well as people who use screen readers may benefit when links are grouped into lists
Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this criterion. The techniques listed only satisfy the success criterion if all of the WCAG 2.0 conformance requirements have been met.
Creating links to skip blocks of repeated material USING one of the following techniques:
Grouping blocks of repeated material in a way that can be skipped, USING one of the following techniques:
HTML Techniques for creating links to skip blocks
Creating HTML links to skip blocks of content (future link)
HTML Techniques for grouping blocks of repeated material
The following are common mistakes that are considered failures of Success Criterion 2.4.1 by the WCAG Working Group.
(No failures currently documented)
Although not required for conformance, the following additional techniques should be considered in order to make content more accessible. Not all techniques can be used or would be effective in all situations.
Providing keyboard access to important links and form controls (future link)
Providing skip links to enhance page navigation (future link)
Providing access keys (future link)
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.
Resources are for information purposes only, no endorsement implied.
(none currently documented)
2.4.2 Web pages have [begin add]descriptive[end add] titles. [LC-625] [LC-841] [LC-1052] [LC-1289] (Level 1)
a resource that is referenced by a URI and is not embedded in another resource, plus any other resources that are used in the rendering or intended to be rendered together with it [LC-862]
[end change]Note: Although any "other resources" would be rendered together with the primary resource, they would not necessarily be rendered simultaneously with each other.
Example 1: A movie-like interactive shopping environment where the user visually moves about a store dragging products off of the shelves around them into a visual shopping cart in front of them. Clicking on a product causes it to be demonstrated with a specification sheet alongside.
Example 2: A Web resource including all embedded images and media.
The intent of this success criterion is to help users find content and orient themselves within it by ensuring that each Web page has a [begin add]descriptive[end add] title. Titles identify the current location without requiring users to read or interpret page content. When titles appear in site maps or lists of search results, users can more quickly identify the content they need. [LC-625]
[begin add]This criterion benefits all users in allowing users to quickly and easily identify whether the information contained in the Web page is relevant to their needs. [end add]
[begin add]People with visual disabilities will benefit from being able to differentiate content when multiple Web pages are open. [end add]
[begin add]People with cognitive disabilities, limited short-term memory and reading disabilities also benefit from the ability to identify content by its title. [end add]
[begin add]This criterion also benefits people with severe mobility impairments whose mode of operation relies on audio when navigating between Web pages. [end add]
These techniques benefit all users. They are especially helpful for users with disabilities that make reading slow and for people with limited short-term memory. [begin delete]People who have difficulty using their hands or who experience pain when doing so will benefit from techniques that reduce the number of keystrokes required to reach the content they need.[end delete] [LC-1105]
[end delete]Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this criterion. The techniques listed only satisfy the success criterion if all of the WCAG 2.0 conformance requirements have been met.
G88: Providing descriptive titles for Web pages [begin add] AND associating a title with a Web page [end add]USING one of the following techniques: [LC-625]
The following are common mistakes that are considered failures of Success Criterion 2.4.2 by the WCAG Working Group.
Although not required for conformance, the following additional techniques should be considered in order to make content more accessible. Not all techniques can be used or would be effective in all situations.
G127: Identifying a Web page's relationship to a larger collection of Web pages USING a technology-specific technique
Identifying the subject of the Web page (future link)
Providing a meaningful name for identifying frames (future link)
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."
[begin delete] An audio file. [end delete]
[begin delete]A podcast is associated with the title "Today's Tech Tips" by setting the id3 property of the .mp3 file.[end delete]
[begin delete] A video clip. [end delete]
[begin delete]A video clip is associated with a title using the meta element in SMIL 1.0 or SMIL 2.0, plus the title attribute of the main par element in the SMIL file.[end delete]
[begin delete] An image. [end delete]
[begin delete]A JPEG image is associated with a title using EXIF metadata stored in the image file. (Note: Current user agents do not read this metadata.)[end delete] [LC-625]
[begin add] A Web application. [end add]
[begin add]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". [end add] [LC-625]
Resources are for information purposes only, no endorsement implied.
Writing Better Web Page Titles How to write titles for Web pages that will enhance search engine effectiveness.
Guidelines for Accessible and Usable Web Sites: Observing Users Who Work With Screen Readers. Theofanos, M.F., and Redish, J. (2003). Interactions, Volume X, Issue 6, November-December 2003, pages 38-51, http://portal.acm.org/citation.cfm?doid=947226.947227
2.4.3 If a Web page [begin delete]or authored component[end delete] can be navigated sequentially, [begin add]focusable components receive focus in an order that follows information and relationships conveyed through presentation.[end add] [begin delete]components receive focus in an order that follows relationships and sequences in the content.[end delete] [LC-745] [LC-628] (Level 1)
[end change]a resource that is referenced by a URI and is not embedded in another resource, plus any other resources that are used in the rendering or intended to be rendered together with it [LC-862]
[end change]Note: Although any "other resources" would be rendered together with the primary resource, they would not necessarily be rendered simultaneously with each other.
Example 1: A movie-like interactive shopping environment where the user visually moves about a store dragging products off of the shelves around them into a visual shopping cart in front of them. Clicking on a product causes it to be demonstrated with a specification sheet alongside.
Example 2: A Web resource including all embedded images and media.
navigated in the order defined for advancing focus from one element to the next with the keyboard [LC-974]
[begin delete]rendering of the content and structure in a form that can be perceived by the user[end delete] [begin change]rendering of the content in a form to be perceived by users [LC-490] [LC-1501] [end change]
The intent of this success criterion is to ensure that when users navigate sequentially through content, they encounter information in an order that reflects the logical relationships in the content. This reduces confusion by letting users form a consistent mental model of the content. [begin add]There may be different orders that reflect logical relationships in the content. For example, move through components in a table one row at a time or one column at a time both reflect the logical relationships in the content. Either order would satisfy this success criterion. [end add] [LC-930]
An additional example of navigation is using arrow key navigation to traverse a tree component. The user can use the up and down arrow keys to move from tree node to tree node. Pressing the left arrow key may expand a node, then using the down arrow key, will move into the newly expanded nodes. This navigation sequence follows the expected sequence for a tree control - as additional items get expanded or collapsed, they are added or removed from the navigation sequence. [LC-930]
[end change]The way that sequential navigation order is determined in Web content is defined by the technology of the content. For example, simple HTML defines sequential navigation via the notion of tabbing order. Dynamic HTML may modify the navigation sequence using scripting along with the addition of a tabindex attribute to allow focus to additional elements. In this case, the navigation should follow relationships and sequences in the content. If no scripting or tabindex attributes are used, the navigation order is the order that components appear in the content stream. (See
HTML 4.01 Specification, section 17.11, "Giving focus to an element").
[LC-974]
These techniques benefit users who navigate documents sequentially and expect the tab order to match the sequential reading order. People with visual impairments or people with disabilities that make reading difficult can become disoriented when tabbing takes focus someplace unexpected.
Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this criterion. The techniques listed only satisfy the success criterion if all of the WCAG 2.0 conformance requirements have been met.
Giving focus to elements in an order that follows sequences and relationships within the content USING one of the following techniques:
The following are common mistakes that are considered failures of Success Criterion 2.4.3 by the WCAG Working Group.
Although not required for conformance, the following additional techniques should be considered in order to make content more accessible. Not all techniques can be used or would be effective in all situations.
(none currently documented)
[begin change]Example that fails to meet the success criterion: [end change]: An on-line subscription form.
[begin change]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.[end change]
[begin add]An individual using a screen magnifier fills in the form. Because of the level of magnification, only a small portion of the page is visible. She tabs through the fields, entering her name, then her street address. However, the next field in tab order is not the field for the city, but the checkbox beside the name of a newsletter. The user assumes that she has provided all of the necessary address information and presses Enter to submit the form. She is surprised when she receives an error message telling her that one or more required fields is incomplete. [LC-1111] [end add]
Resources are for information purposes only, no endorsement implied.
(none currently documented)
2.4.4 [begin delete]Each link is programmatically associated with text from which its purpose can be determined.[end delete] [begin add]The purpose of each link can be determined from the link text and its programmatically determined link context [end add]. [LC-497] [LC-872] (Level 1)
Editorial Note: This item may be moved back to level 2 if it is determined that it causes pages to fail at level 1 that are, in fact, accessible. (@@ editors to review how to describe "at risk" here)
Additional information that can be programmatically determined from relationships with a link; and
can be extracted, combined with the link text, and presented to users in different modalities.
Example 1: Screen readers provide commands to read the current sentence when focus is on a link.
Example 2: Examples of information that can be extracted, combined with link text, and presented to users in different modalities include text that is in the same sentence, 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.
The intent of this success criterion is to help users understand the purpose of each link so they can decide whether they want to follow the link. This is generally achieved by reading the link itself. Assistive technology has the ability to provide users with a list of links that are on the Web page. Link text that is as meaningful as possible will aid users who want to choose from this list of links. Meaningful link text also helps those who wish to tab from link to link. Meaningful links help users choose which links to follow without requiring complicated strategies to understand the page.
[end change]In some situations, authors may want to provide part of the description of the link in the nearby text. In this case the user should be able to identify the purpose of the link without moving focus from the link. In other words, they can arrive on a link and find out more about it without losing their place. This can be achieved by putting the description of the link in the same sentence, paragraph, list item, or table cell as the link because these are directly associated with the link iteself. These descriptions will be most useful to the user if the description of the link precedes the link. (For instance, if you must use ambiguous link text, it is better to put it at the end of the sentence that describes its destination, rather than putting the ambiguous phrase at the beginning of the sentence.) This is because if the description follows the link, there can be confusion and difficulty for screen reader users who are reading through the page in order (top to bottom).
[end add]Links with the same destination should have the same descriptions (per Success Criterion 3.2.4), but links with different purposes and destinations should have different descriptions. [LC-497]
[end add]Note: There may be situations where the purpose of the link is is supposed to be unknown or obscured. For instance, a game may have links identified only as door #1, door #2, and door #3. This link text would be sufficient because the purpose of the links is to create suspense for all users.
This success criterion helps people with motion impairment by letting them skip links that they are not interested in, avoiding the keystrokes needed to visit the referenced content and then returning to the current content.
People with cognitive limitations will not become disoriented by multiple means of navigation to and from content they are not interested in.
[begin change]People with visual disabilities will be able to determine the purpose of a link by exploring the link's context. [end change] [LC-497]
Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this criterion. The techniques listed only satisfy the success criterion if all of the WCAG 2.0 conformance requirements have been met.
G91: Providing link text that describes the purpose of a link
[begin change] G53: Identifying the purpose of a link using link text combined with the text of the enclosing sentence [end change]
Providing a supplemental description of the purpose of a link USING one of the following techniques:
[begin change]Identifying the purpose of a link using link text combined with programmatically determined link context USING one of the following techniques:[end change]
The following are common mistakes that are considered failures of Success Criterion 2.4.4 by the WCAG Working Group.
Although not required for conformance, the following additional techniques should be considered in order to make content more accessible. Not all techniques can be used or would be effective in all situations.
A link contains text that gives a description of the information at that URL
[begin change]A page contains the sentence "There was much bloodshed during the Medieval period of history." Where "Medieval period of history" is a link.[end change]
A link is preceded by a text description of the information at that URL
[begin change]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.[end change]
Both an icon and text are included in the same link
[begin change]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.[end change]
A list of book titles
[begin change]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."[end change]
News article summaries
[begin change]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.[end change] [LC-497]
Resources are for information purposes only, no endorsement implied.
2.4.5 More than one way is available to locate content within a set of Web pages where content is not the result of, or a step in, a process [begin delete] or task [LC-496] [end delete]. (Level 2)
collection of Web pages that have a specific relationship to each other and that are created as a body of work by an author, group or organization [LC-711] [LC-916]
Note: Different language versions would be considered different bodies of work.
Example: A set of Web pages that make up a report, a test, an exercise, a catalog, or an application.
series of user actions where each action is required in order to complete an activity
Example 1: A series of Web pages on a shopping site requires users to view alternative products and prices, 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.
The intent of this success criterion is to make it possible for users to locate content in a manner that best meets their needs. Users may find one technique easier or more comprehensible to use than another.
Providing an opportunity to navigate sites in more than one manner can help people find information faster. Users with visual impairments may find it easier to navigate to the correct part of the site by using a search, rather than scrolling through a large navigation bar using a screen magnifier or screen reader. A person with cognitive disabilities may prefer a table of contents or site map that provides an overview of the site rather than reading and traversing through several Web pages. Some users may prefer to explore the site in a sequential manner, moving from Web page to Web page in order to best understand the concepts and layout.
Individuals with cognitive limitations may find it easier to use search features than to use a hierarchical navigation scheme that be difficult to understand.
Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this criterion. The techniques listed only satisfy the success criterion if all of the WCAG 2.0 conformance requirements have been met.
Using two or more of the following techniques:
Providing a search engine to help users find content (future link)
The following are common mistakes that are considered failures of Success Criterion 2.4.5 by the WCAG Working Group.
(No failures currently documented)
Although not required for conformance, the following additional techniques should be considered in order to make content more accessible. Not all techniques can be used or would be effective in all situations.
Including information about presentation modes in tables of contents and concept maps (future link)
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.
Resources are for information purposes only, no endorsement implied.
(none currently documented)
2.4.6 [begin delete]Titles, [end delete]Headings and labels are descriptive. [LC-625] [LC-839] (Level 2)
text [begin delete], image, or sound[end delete] [begin add]or other component with a text alternative [end add] that is presented to a user to identify a component within Web content
The intent of this success criterion is to help users understand what information is contained in Web pages and how that information is organized. When [begin delete]titles and [end delete]headings are clear and descriptive, users can find the information they seek more easily, and they can understand the relationships between different parts of the content more easily. Descriptive labels help users identify specific components within the content. [LC-625]
Descriptive [begin change]headings[end change] are especially helpful for users who have disabilities that make reading slow and for people with limited short-term memory. These people benefit when section titles make it possible to predict what each section contains.
People who have difficulty using their hands or who experience pain when doing so will benefit from techniques that reduce the number of keystrokes required to reach the content they need.
This success criterion helps people who use screen readers by ensuring that [begin change]labels[end change] and headings are meaningful when read out of context, for example, in a Table of Contents, or when jumping from heading to heading within a page.
This success criterion may also help users with low vision who can see only a few words at a time. [LC-625]
Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this criterion. The techniques listed only satisfy the success criterion if all of the WCAG 2.0 conformance requirements have been met.
Note: [begin delete]Titles, h[end delete]Headings and labels must be programmatically determined, per success criterion 1.3.1.
The following are common mistakes that are considered failures of Success Criterion 2.4.6 by the WCAG Working Group.
(No failures currently documented)
Although not required for conformance, the following additional techniques should be considered in order to make content more accessible. Not all techniques can be used or would be effective in all situations.
Using unique section headings in a Web Page (future link)
Starting section headings with unique information (future link)
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.
Resources are for information purposes only, no endorsement implied.
Methods for Designing Usable Web Sites Methods for collecting, writing, and revising Web content to make it easy to use.
How Users Read on the Web A study showing that most users scan Web pages rather than reading them word by word.
Applying Writing Guidelines to Web Pages A report on the effects of making Web sites concise, easy to scan, and objective.
2.4.7 Information about the user's location within a set of Web pages is available. (Level 3)
[LC-711]collection of Web pages that have a specific relationship to each other and that are created as a body of work by an author, group or organization [LC-711] [LC-916]
Note: Different language versions would be considered different bodies of work.
Example: A set of Web pages that make up a report, a test, an exercise, a catalog, or an application.
The intent of this success criterion is to provide a way for the user to orient herself within a set of Web pages, a Web site, or a Web application and find related information.
This success criterion is helpful for people with a short attention span who may become confused when following a long series of navigation steps to a Web page. It is also helpful when a user follows a link directly to a page deep within a set of Web pages and needs to navigate that Web site to understand the content of that page or to find more related information.
Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this criterion. The techniques listed only satisfy the success criterion if all of the WCAG 2.0 conformance requirements have been met.
The following are common mistakes that are considered failures of Success Criterion 2.4.7 by the WCAG Working Group.
(No failures currently documented)
Although not required for conformance, the following additional techniques should be considered in order to make content more accessible. Not all techniques can be used or would be effective in all situations.
Providing a link to the home page or main page (future link)
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.
Resources are for information purposes only, no endorsement implied.
2.4.8 The purpose of each link can be [begin delete] programmatically determined [end delete] [begin add]identified[end add] from the link text. [LC-497] (Level 3)
determined by software from [begin add]author-supplied[end add] data provided in a [begin delete] user-agent-supported manner such that the[end delete] [begin add]way that different[end add] user agents, including assistive technologies, can extract and present this information to users in different modalities [LC-756] [LC-1502]
Example: Determined in a mark-up language from elements and attributes that are accessed directly by commonly available assistive technology.
[end add]Example: Determined from technology-specific data structures in a non-mark-up language and exposed to assistive technology via an accessibility API that is supported by commonly available assitive technology.
[end add]The intent of this success criterion is to help users understand the purpose of each link in the content, so they can decide whether they want to follow it. [begin change]Links with the same destination should have the same descriptions (per Success Criterion 3.2.4), but links with different purposes and destinations should have different descriptions. Because the purpose of a link can be identified from its link text, links can be understood when they are out of context, such as when the user agent provides a list of all the links on a page. [end change] [LC-497]
This success criterion helps people with motion impairment by letting them skip Web pages that they are not interested in, avoiding the keystrokes needed to visit the referenced content and then return to the current content.
People with cognitive limitations will not become disoriented by extra navigation to and from content they are not interested in.
People with visual disabilities will benefit from not losing their place in the content when they return to the original page. The screen reader's list of links is more useful for finding information because the target of the links are described.
Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this criterion. The techniques listed only satisfy the success criterion if all of the WCAG 2.0 conformance requirements have been met.
G91: Providing link text that describes the purpose of a link USING one of the following techniques:
Providing a supplemental description of the purpose of a link USING one of the following techniques:
The following are common mistakes that are considered failures of Success Criterion 2.4.8 by the WCAG Working Group.
(No failures currently documented)
Although not required for conformance, the following additional techniques should be considered in order to make content more accessible. Not all techniques can be used or would be effective in all situations.
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."
Resources are for information purposes only, no endorsement implied.
2.4.9 Where content is organized into sections, the sections are indicated with headings. (Level 3)
Editorial Note: This SC was accepted 19 April per a resolution to Issue 627. @@ Sufficient techniques needed. Intent, benefits, examples, resources also need to be drafted.
Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this criterion. The techniques listed only satisfy the success criterion if all of the WCAG 2.0 conformance requirements have been met.
Organizing a page using headers (future link) (HTML)
Using titled frames to organize content that is updated (future link) (HTML)
The following are common mistakes that are considered failures of Success Criterion 2.4.9 by the WCAG Working Group.
(No failures currently documented)
Although not required for conformance, the following additional techniques should be considered in order to make content more accessible. Not all techniques can be used or would be effective in all situations.
Using the 'live' property to mark live regions (future link) (ARIA)
The intent of this guideline is to allow text content to be read by users and by assistive technology, and to ensure that information necessary for understanding it is available.
People with disabilities experience text in many different ways. For some the experience is visual; for some it is auditory; for some it is tactile; for still others it is both visual and auditory. Some users experience great difficulty in recognizing written words yet understand extremely complex and sophisticated documents when the text is read aloud, or when key processes and ideas are illustrated visually or interpreted as sign language. For some users, it is difficult to infer the meaning of a word or phrase from context, especially when the word or phrase is used in an unusual way or has been given a specialized meaning; for these users the ability to read and understand may depend on the availability of specific definitions or the expanded forms of acronyms or abbreviations. User agents, including speech-enabled as well as graphical applications, may be unable to present text correctly unless the language and direction of the text are identified; while these may be minor problems for most users, they can be enormous barriers for users with disabilities. In cases where meaning cannot be determined without pronunciation information (for example, certain Japanese Kanji, example), pronunciation information must be available as well
Specific techniques for meeting each success criterion for this guideline are listed in the How to Meet sections for each success criterion (listed below). If there are techniques, however, for addressing this guideline that do not fall under any of the success criteria, they are listed here. These techniques are not required or sufficient for meeting any success criteria, but can make certain types of Web content more accessible to more people.
[begin add]Setting expectations about auto-generated or user-contributed content (future link) [LC-683] [end add]
[begin add]Providing sign language interpretation for all content (future link) [LC-893] [end add]
Using the clearest and simplest language appropriate for the content (future link) [LC-1255]
[end add]Avoiding text that is fully justified (to both left and right margins) in a way that causes poor spacing between words or characters (future link) [LC-1253]
[end add]Using left-justified text for languages that are written left to right (future link)
[end add]Using appropriate justification for languages that are written right-to-left (future link)
[end add]Limiting text column width (future link)
[end add]Avoiding overuse of different styles on individual pages and in sites (future link) [LC-1253]
[end add]Using images, illustrations, video, audio, or symbols to clarify meaning (future link)
[end add]Providing practical examples to clarify content (future link)
[end add]Using a light pastel background rather than a white background behind black text (future link)
[end add]Highlighting a link or control when the mouse hovers over it (future link)
[end add]Avoiding the use of unique interface controls unnecessarily (future link)
[end add]Using upper and lower case according to the spelling rules of the text language (future link)
[end add]Avoiding unusual foreign words (future link)
[end add][LC-840]
3.1.1 The [begin change]default[end change] human language [begin delete]or languages[end delete] of [begin change]each[end change] Web page [begin add]within the content[end add] can be programmatically determined. [LC-1371] [LC-1376] [LC-501] (Level 1)
[begin add]language that is spoken, written or signed (visually or tactilely) by humans to communicate with one another[end add] [begin delete]languages used by humans to communicate, including spoken, written, and signed languages[end delete] [LC-1184] [LC-1500]
Note: See also sign language.
a resource that is referenced by a URI and is not embedded in another resource, plus any other resources that are used in the rendering or intended to be rendered together with it [LC-862]
[end change]Note: Although any "other resources" would be rendered together with the primary resource, they would not necessarily be rendered simultaneously with each other.
Example 1: A movie-like interactive shopping environment where the user visually moves about a store dragging products off of the shelves around them into a visual shopping cart in front of them. Clicking on a product causes it to be demonstrated with a specification sheet alongside.
Example 2: A Web resource including all embedded images and media.
determined by software from [begin add]author-supplied[end add] data provided in a [begin delete] user-agent-supported manner such that the[end delete] [begin add]way that different[end add] user agents, including assistive technologies, can extract and present this information to users in different modalities [LC-756] [LC-1502]
Example: Determined in a mark-up language from elements and attributes that are accessed directly by commonly available assistive technology.
[end add]Example: Determined from technology-specific data structures in a non-mark-up language and exposed to assistive technology via an accessibility API that is supported by commonly available assitive technology.
[end add]The intent of this success criterion is to ensure that content developers provide information in the Web page that user agents need to present text and other linguistic content correctly. Both assistive technologies and conventional user agents can render text more accurately when the language of the Web page is identified. Screen readers can load the correct pronunciation rules. Visual browsers can display characters and scripts correctly. Media players can show captions correctly. As a result, users with disabilities will be better able to understand the content.
"Language declarations in HTML and XHTML have nothing to do with character encoding or the direction of text … [T]here is not always a one-to-one mapping between language and script, and therefore directionality. For example, Azerbaijani can be written using both right-to-left and left-to-right scripts." (From Relationships between language, character encoding and directionality.) Therefore, there are separate mechanisms for declaring the language and directionality of text. The default text direction is left-to-right which means that direction only needs to be specified if it is right-to-left. [LC-1383]
[end delete]The default human language of the Web page is the default text-processing language as discussed in Internationalization Best Practices: Specifying Language in XHTML & HTML Content. When a Web page uses several languages, the default text-processing language is the language which is used most. (If several languages are used equally, the first language used should be chosen as the default human language.) [LC-1376]
[end add]Note: [begin add]For multilingual sites targeting Conformance Level A, the Working Group strongly encourages developers to follow SC 3.1.2 as well even though that is a Level 2 success criterion.[end add] [LC-1376]
This success criterion helps:
people who use screen readers or other technologies that convert text into synthetic speech;
people who find it difficult to read written material with fluency and accuracy, such as recognizing characters and alphabets or decoding words;
[end change]people with certain cognitive, language and learning disabilities also use text-to-speech software, which can also benefit from language markup; [LC-1124]
[end add]people who rely on captions for multimedia.
Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this criterion. The techniques listed only satisfy the success criterion if all of the WCAG 2.0 conformance requirements have been met.
Identifying [begin change]default[end change] human language(s) USING one of the following techniques:
[begin delete] Identifying [begin change]default[end change] human language(s) USING a technology-specific technique listed below AND Identifying the primary text direction USING the following techniques: [end delete]
The following are common mistakes that are considered failures of Success Criterion 3.1.1 by the WCAG Working Group.
(No failures currently documented)
Although not required for conformance, the following additional techniques should be considered in order to make content more accessible. Not all techniques can be used or would be effective in all situations.
Specifying the [begin change]default[end change] language in the HTTP header (future link)
[begin delete]using dc:lang in the meta element to specify language or multiple languages (future link) [LC-1375] [end delete]
using http or the Content-Language meta tag for metadata (future link)
[begin delete] Specifying the direction of text (future link)[end delete]
Example 1. A Web page with content in two languages
A Web page produced in Germany includes content in both German and English, but most of the content is in German. The [begin change]default[end change] human language is identified as German (de).
[begin delete] Example 2. A Web page whose [begin change]default[end change] human language is written right-to-left [end delete]
[begin delete]All of the content in a Web page is written in Hebrew. The [begin change]default[end change] human language is identified as Hebrew (he) [begin delete]and the direction is identified as right-to-left [LC-1383] [end delete].[end delete]
Resources are for information purposes only, no endorsement implied.
[begin add] Internationalization Best Practices: Specifying Language in XHTML & HTML Content [LC-1376] [LC-1378] [end add]
d140 Learning to read. 2001. International Classification of Functioning, Disabilities, and Health. World Health Organization
[end add]3.1.2 The human language of each passage or phrase in the [begin delete] Web page [end delete] [begin add]content[end add] can be programmatically determined [LC-502] . (Level 2)
[begin add]language that is spoken, written or signed (visually or tactilely) by humans to