Understanding Guideline 1.1:
Provide text alternatives for any non-text content so that it can be changed into other forms people need such as large print, braille, speech, symbols or simpler language
Intent of Guideline 1.1
The purpose of this guideline is to ensure that all non-text content is also available in text. "Text" refers to electronic text, not an image of text. Electronic text has the unique advantage that it can be rendered visually, auditorially, 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.
Advisory Techniques for Guideline 1.1 (not success criteria specific)
Specific techniques for meeting each success criterion for this guideline are listed in the understanding 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.
- All advisory techniques for this guideline relate to specific success criteria and are listed below.
Understanding Success Criterion 1.1.1 (Non-text Content)
[begin change]
[begin change] 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 A)
[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 Guideline 4.1.)
[LC-738]
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]text alternatives that identify and describe the purpose of the non-text content are provided and alternative[end change] forms [begin add]in different modalities are[end add] 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.
[end change] Key Terms
- non-text content
[begin delete] 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
[end delete] Note: This includes ASCII Art (which is a pattern of characters) [begin add]and leetspeak (which is character substitution).
[LC-796]
[end add]
- text alternative
programmatically determined text that is used in place of non-text content, or text that is used in addition to non-text content and referred to from the programmatically determined text
[begin add] Example: An image of a chart is described in text in the paragraph after the chart. The short text-alternative for the chart indicates that a description follows.
[LC-1507]
- name
text by which software can identify a component within Web content to the user
Note 1:
The name may be hidden and only exposed by assistive technology, whereas a label is presented [begin add]to all users.[end add]
[begin delete]even without Assistive technology (as used in this document 732
)
[end delete] In many (but not all) cases, the label [begin add]and the name are the same.[end add]
[begin delete]is a display of the name[end delete]
[begin add] Note 2:
This is unrelated to the name attribute in HTML.
[end add] - multimedia
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]
- live audio-only
A time-based live presentation that contains only audio (no video and no interaction)
- live video-only
A time-based live presentation that contains only video (no audio and no interaction)
- must be presented in non-text format
would be invalid if presented in text
[LC-1506]
Example: Color blindness test, hearing test, vision exercise, spelling test.
- specific sensory experience
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]
- label
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
Note:
[begin add]See also name.
[LC-847]
[end add]
- CAPTCHA
initialism for "Completely Automated Public Turing test to tell Computers and Humans Apart"
Note 1:
CAPTCHA tests often involve asking the user to type in text that is displayed in an obscured image or audio file.
Note 2:
A Turing test is any system of tests designed to differentiate a human from a computer. It is named after famed computer scientist Alan Turing. The term was coined by researchers at Carnegie Mellon University. [CAPTCHA]
- pure decoration
serving only an aesthetic purpose, providing no information, and having no functionality
[begin add] Note: Text is only purely decorative if the words can be rearranged or substituted without changing their purpose.
[begin add] Example: The cover page of a dictionary has random words in very light text in the background.
- Assistive technology ([begin change]as used in this document
[LC-732]
[end change])
a user agent that [begin add]both[end add]:
[begin change] provides services to meet the requirements of users with disabilities that go beyond those offered by the mainstream user agents. Such services include alternative presentations (e.g., as synthesized speech or magnified content), alternative input methods (e.g., voice), additional navigation or orientation mechanisms, and content transformations (e.g., to make tables more accessible)[begin add], and[end add]
[LC-1178]
[end change] usually relies on services (such as retrieving Web content and parsing markup) provided by one or more other mainstream user agents. Assistive technologies communicate data and messages with mainstream user agents by using and monitoring APIs
Note 1:
[begin add]In this definition, user agents are user agents in the general sense of the term. That is, any software that retrieves and [begin change]presents[end change] Web content for users. The mainstream 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]Mainstream 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];
[begin add] 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.
Intent of this Success Criterion
The intent of this success criterion is to make information conveyed by non-text content accessible through the use of a text alternative. Text alternatives are a primary way for making information accessible because they can be rendered through any sensory modality (for example, visual, auditory or tactile) to match the needs of the user. Providing text alternatives allows the information to be rendered in a variety of ways by a variety of user agents. For example, a person who cannot see a picture can have the text alternative read aloud using synthesized speech. A person who cannot hear an audio file can have the text alternative displayed so that he or she can read it. In the future, text alternatives will also allow information to be more easily translated into sign language or into a simpler form of the same language.
Additional information
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 [begin change]is not covered by one of the other situations listed below[end change],
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).
[begin change]
For non-text content that is a control or accepts user input
, such as images used as submit buttons or complex animations, a name is provided to describe the purpose of the non-text content so that the person at least knows what the non-text content is and why it is there.
[end change]
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]
[begin add]
Sometimes there are non-text exercises that are used to prove you are human. To avoid spam robots and other software from gaining access to a site a device called a CAPTCHA is used. These usually involve visual or auditory tasks that are beyond the current capabilities of web robots. Providing a text alternative to them would however make them operable by Robots, thus defeating their purpose. In this case a text alternative would describe the purpose of the CAPTCHA, and alternate forms using different modalities would be provided to address the needs of people with different disabilities.
[end add]
Sometimes 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.
Specific Benefits of Success Criterion 1.1.1:
[begin change] 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] [begin 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.
Techniques for Addressing Success Criterion 1.1.1
Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this success criterion. The techniques listed only satisfy the success criterion if all of the WCAG 2.0 conformance requirements have been met.
Sufficient Techniques
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.
Situation F: If the non-text content should be ignored by assistive technology:
Implementing or marking the non-text content so that it will be ignored by assistive technology using one of the technology-specific techniques listed below
Providing short text alternatives in HTML
Providing long text alternatives in HTML
Common Failures Identified by the Working Group
The following are common mistakes that are considered failures of Success Criterion 1.1.1 by the WCAG Working Group.
Additional Techniques (Advisory) for 1.1.1
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.
General Techniques for Informative Non-Text Content (Advisory)
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)
General Techniques for Live Non-Text Content (Advisory)
[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)
HTML Techniques (Advisory)
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)
CSS Techniques (Advisory)
Using CSS margin and padding rules instead of spacer images (future link)
Using CSS background, :before or :after rules for decorative images instead of img elements (future link)
Displaying empty table cells (future link)
Examples of Success Criterion 1.1.1
A data chart
A bar chart compares how many widgets were sold in June, July, and August. The short label says, "Figure one - Sales in June, July and August." The longer description identifies the type of chart, provides a high-level summary of the data [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]
[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]
Related Resources
Resources are for information purposes only, no endorsement implied.
Understanding Guideline 1.2:
Provide synchronized alternatives for multimedia
Intent of Guideline 1.2
The purpose of this guideline is to provide access to multimedia. Multimedia is defined in the glossary as:
multimedia: audio or video synchronized with another type of media and/or with time-based interactive components
Note that an audio file accompanied by interaction is covered here, as is a video-only file that involves interaction. These are covered because interaction must take place at a particular time. Having a text transcript that said, "for more information, click now," would not be very helpful since the reader would have no idea when the audio said, "now." As a result, synchronized captions would be needed.
Sometimes, there is so much dialogue that audio description cannot fit into existing pauses in the dialogue. The option at Level A 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 AAA) 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]
Advisory Techniques for Guideline 1.2 (not success criteria specific)
Specific techniques for meeting each success criterion for this guideline are listed in the understanding 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] Providing
audio description for live multimedia (future link)
[LC-487]
[end add]
Understanding Success Criterion 1.2.1 (Captions (Prerecorded))
- captions
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.
- multimedia
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 alternatives to text
[begin add] 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 include non-speech information conveyed through sound, including meaningful sound effects.
[begin add] 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] [begin 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 [begin add]presents no more information than is already presented in text,[end add] but 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] Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this success criterion. The techniques listed only satisfy the success criterion if all of the WCAG 2.0 conformance requirements have been met.
The following are common mistakes that are considered failures of Success Criterion 1.2.1 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.
Providing a note saying "No sound is used in this clip" for video-only clips (future link)
Using SMIL 1.0 to provide captions for all languages for which there are audio tracks (future link)
Using SMIL 2.0 to provide captions for all languages for which there are audio tracks (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.
[begin add] 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] [begin 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)
Understanding Success Criterion 1.2.2 (Audio Description or Full Text Alternative)
- audio description
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.)
[begin add] Note 3:
Also called "video description" and "descriptive narration."
[end add] -
[begin change]full text alternative for multimedia including any interaction
[LC-810]
[end change]
[begin change] document including correctly sequenced text descriptions of all visual settings, actions, speakers, and non-speech sounds, and transcript of all dialogue combined with a means of achieving any outcomes that are achieved using interaction (if any) during the multimedia
[end change] 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.
- multimedia
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 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 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 the same 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]
[begin change] 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 success 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 1.2.2 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.
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.
Understanding Success Criterion 1.2.3 (Captions (Live))
1.2.3
Captions are provided for live
multimedia. (Level AA)
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]
- captions
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.
- multimedia
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.
Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this success criterion. The techniques listed only satisfy the success criterion if all of the WCAG 2.0 conformance requirements have been met.
The following are common mistakes that are considered failures of Success Criterion 1.2.3 by the WCAG Working Group.
(No failures currently documented)
Resources are for information purposes only, no endorsement implied.
Understanding Success Criterion 1.2.4 (Audio Description)
- audio description
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.)
[begin add] Note 3:
Also called "video description" and "descriptive narration."
[end add] - multimedia
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]
Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this success criterion. The techniques listed only satisfy the success criterion if all of the WCAG 2.0 conformance requirements have been met.
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.
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.
Understanding Success Criterion 1.2.5 (Sign Language)
- sign language interpretation
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]
- multimedia
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]
[begin change] 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 success 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 1.2.5 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.
Understanding Success Criterion 1.2.6 (Audio Description (Extended))
- extended audio description
audio description that is added to an audiovisual presentation by pausing the video so that there is time to add additional description
Note: This technique is only used when the sense of the video would be lost without the additional audio description.
- multimedia
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 success 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 1.2.6 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.
Understanding Success Criterion 1.2.7 (Full Text Alternative)
Key Terms
-
[begin change]full text alternative for multimedia including any interaction
[LC-810]
[end change]
[begin change] document including correctly sequenced text descriptions of all visual settings, actions, speakers, and non-speech sounds, and transcript of all dialogue combined with a means of achieving any outcomes that are achieved using interaction (if any) during the multimedia
[end change] 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.
- multimedia alternatives to text
[begin add] 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.
Intent of this Success Criterion
The intent of this success criterion is to make audio visual material available to individuals whose vision is too poor to reliably read captions and whose hearing is too poor to reliably hear dialogue and audio description. This is done by providing a full text alternative for multimedia including any interaction.
This approach involves providing all of the information in the multimedia (both visual and auditory) in text form. A full text alternative for multimedia including any interaction provides a running description of all that is going on in the multimedia content. The full text alternative for multimedia reads something like a book. Unlike audio description, the description of the video portion is not constrained to just the pauses in the existing dialogue. Full descriptions are provided of all visual information, including visual context, actions and expressions of actors, and any other visual material. In addition, non-speech sounds (laughter, off-screen voices, etc.) are described, and transcripts of all dialogue are included. The sequence of descriptions and dialogue transcripts is the same as the sequence in the multimedia itself. As a result, the full text alternative for multimedia can provide a much more complete representation of the multimedia content than audio description alone.
If there is any interaction as part of the multimedia presentation (e.g. "press now to answer the question") then the full text alternative for multimedia would provide hyperlinks or whatever is needed to provide parallel functionality.
Individuals whose vision is too poor to reliably read captions and whose hearing is too poor to reliably hear dialogue can access the full text alternative for multimedia by using a refreshable braille display.
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]
Specific Benefits of Success Criterion 1.2.7:
Techniques for Addressing Success Criterion 1.2.7
Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this success criterion. The techniques listed only satisfy the success criterion if all of the WCAG 2.0 conformance requirements have been met.
Common Failures Identified by the Working Group
The following are common mistakes that are considered failures of Success Criterion 1.2.7 by the WCAG Working Group.
(No failures currently documented)
Additional Techniques (Advisory) for 1.2.7
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.
Examples of Success Criterion 1.2.7
Example 1. full text alternative for multimedia for a training video
A community center purchases a Training video for use by its clients and puts it on the center’s intranet. The video involves explaining use of a new technology and has a person talking and showing things at the same time. The community center provides a full text alternative for multimedia that all clients, including those who can neither see the demonstrations nor hear the explanations in the multimedia, can use to better understand what is being presented.
Related Resources
Resources are for information purposes only, no endorsement implied.
(none currently documented)
Understanding Guideline 1.3:
Create content that can be presented in different ways (for example spoken aloud, simpler layout, etc.) without losing information or structure488
1201
Intent of Guideline 1.3
The purpose of this guideline is to ensure that all information is available in a form that can be perceived by all users. If all of the information is available in a form that can be determined by software, then it can be presented to users in different ways (visually, audibly, tactilely etc.). If information is embedded in a particular presentation in such a way that the [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.
structure: the way the parts of a Web page are organized in relation to each other; and the way a collection of Web pages is organized
presentation: rendering of the content in a form that can be perceived by users
Advisory Techniques for Guideline 1.3 (not success criteria specific)
Specific techniques for meeting each success criterion for this guideline are listed in the understanding 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.
Understanding Success Criterion 1.3.1 (Info and Relationships)
Key Terms
- relationships
[begin add]meaningful associations between distinct pieces of content
[LC-1427]
[end add]
- presentation
[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]
- programmatically determined
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]
[begin add] Example: Determined in a mark-up language from elements and attributes that are accessed directly by commonly available assistive technology.
[end add] [begin 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 assistive technology.
[end add] - user agent
any software that retrieves and [begin change]presents[end change] 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]
- Assistive technology ([begin change]as used in this document
[LC-732]
[end change])
a user agent that [begin add]both[end add]:
[begin change] provides services to meet the requirements of users with disabilities that go beyond those offered by the mainstream user agents. Such services include alternative presentations (e.g., as synthesized speech or magnified content), alternative input methods (e.g., voice), additional navigation or orientation mechanisms, and content transformations (e.g., to make tables more accessible)[begin add], and[end add]
[LC-1178]
[end change] usually relies on services (such as retrieving Web content and parsing markup) provided by one or more other mainstream user agents. Assistive technologies communicate data and messages with mainstream user agents by using and monitoring APIs
Note 1:
[begin add]In this definition, user agents are user agents in the general sense of the term. That is, any software that retrieves and [begin change]presents[end change] Web content for users. The mainstream 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]Mainstream 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];
[begin add] 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.
Intent of this Success Criterion
The intent of this success criterion is to ensure that information and relationships that are implied by visual or auditory formatting are preserved when the presentation format changes. For example, the presentation format changes when the content is read by a screen reader or when a user style sheet is substituted for the style sheet provided by the author.
Sighted users perceive structure through various visual cues — headings are often in a larger, bold font separated from paragraphs by blank lines; list items are preceded by a bullet and perhaps indented; paragraphs are separated by a blank line; items that share a common characteristic are organized into tabular rows and columns; form fields may be positioned as groups that share text labels; a different background color may be used to indicate that several items are related to each other; [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.
[begin change]
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] [begin add] 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] [begin 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]
Specific Benefits of Success Criterion 1.3.1:
[begin change] This success criterion helps people with different disabilities by allowing user agents to adapt content according to the needs of individual users.
[end change] 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).
Users who are deaf-blind using braille (text) refreshable displays may be unable to access color-dependent information.
Techniques for Addressing Success Criterion 1.3.1
Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this success criterion. The techniques listed only satisfy the success criterion if all of the WCAG 2.0 conformance requirements have been met.
[begin change]
Sufficient Techniques
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.
Situation A: The technology provides semantic structure to make information and relationships conveyed through presentation programmatically determinable:
[begin add] 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:
Situation B: The technology in use does NOT provide the semantic structure to make the information and relationships conveyed through presentation programmatically determinable:
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]
Common Failures Identified by the Working Group
The following are common mistakes that are considered failures of Success Criterion 1.3.1 by the WCAG Working Group.
Additional Techniques (Advisory) for 1.3.1
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.
Examples of Success Criterion 1.3.1
[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.
Understanding Success Criterion 1.3.2 (Meaningful Sequence)
1.3.2
[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 A)
Key Terms
- programmatically determined
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]
[begin add] Example: Determined in a mark-up language from elements and attributes that are accessed directly by commonly available assistive technology.
[end add] [begin 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 assistive technology.
[end add]
Intent of this Success Criterion
The intent of this success criterion is to enable a user agent to provide an alternative presentation of content while preserving the reading order needed to perceive meaning. It is important that it be possible to programmatically determine at least one sequence of the content that makes sense. [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.
Specific Benefits of Success Criterion 1.3.2:
Techniques for Addressing Success Criterion 1.3.2
Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this success criterion. The techniques listed only satisfy the success criterion if all of the WCAG 2.0 conformance requirements have been met.
Common Failures Identified by the Working Group
The following are common mistakes that are considered failures of Success Criterion 1.3.2 by the WCAG Working Group.
Additional Techniques (Advisory) for 1.3.2
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.
Examples of Success Criterion 1.3.2
Example 1: In a multi-column document, the linear presentation of the content flows from the top of a column to the bottom of the column, then to the top of the next column.
Example 2: CSS is used to position a navigation bar, the main story on a page, and a side story. The visual presentation of the sections does not match the programmatically determined order, but the meaning of the page does not depend on the order of the sections.
Understanding Success Criterion 1.3.3 (Size, Shape, Location)
1.3.3
[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 A)
Intent of this Success Criterion
The intent of this success criterion is to ensure that all users can access instructions for using the content, even when they cannot perceive shape or size or use information about spatial location or orientation.
Some content relies on knowledge of the shape or position of objects that are not available from the structure of the content (for example, "round button" or "button to the right").
Some users with disabilities are not able to perceive shape or position due to the nature of the assistive technologies they use.
This success criterion requires that additional information be provided to clarify anything that is dependent on this kind of information.
Providing information using shape and/or location, however, is an effective method for many users including those with cognitive limitations.
This provision should not discourage those types of cues as long as the information is also provided in other ways.
Specific Benefits of Success Criterion 1.3.3:
Techniques for Addressing Success Criterion 1.3.3
Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this success criterion. The techniques listed only satisfy the success criterion if all of the WCAG 2.0 conformance requirements have been met.
Common Failures Identified by the Working Group
The following are common mistakes that are considered failures of Success Criterion 1.3.3 by the WCAG Working Group.
Additional Techniques (Advisory) for 1.3.3
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 change] 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]
Examples of Success Criterion 1.3.3
[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 on-line multi-page survey [end add]
[begin add]An on-line multi-page survey uses a link implemented as a green arrow icon placed in the lower right hand corner of the content to move from one survey page to the next. The arrow is clearly labeled with "Next" and the instructions state, "To move to the next section of the survey, select the green arrow icon labeled 'Next' in the lower right below the last survey question." This example uses both positioning, color and labeling to help identify the icon.[end add]
[LC-1082]
[begin delete]
Understanding Success Criterion 1.3.4 (REMOVED) (Text Variations)
[begin delete]
1.3.4 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 AA)
[end delete] Key Terms
- variations in presentation of text
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]
- programmatically determined
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]
[begin add] Example: Determined in a mark-up language from elements and attributes that are accessed directly by commonly available assistive technology.
[end add] [begin 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 assistive technology.
[end add]
Intent of this Success Criterion
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.
Specific Benefits of Success Criterion 1.3.4 (REMOVED):
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.
[begin delete]
Techniques for Addressing Success Criterion 1.3.4 (REMOVED)
Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this success criterion. The techniques listed only satisfy the success criterion if all of the WCAG 2.0 conformance requirements have been met.
[begin delete]
Sufficient Techniques
Using text to convey information that is conveyed by variations in presentation of text
Marking emphasized or special text using one of the following techniques:
Using semantic markup to mark emphasized or special text
[begin delete]
Common Failures Identified by the Working Group
The following are common mistakes that are considered failures of Success Criterion 1.3.4 (REMOVED) by the WCAG Working Group.
Failure due to using CSS to create variations in presentation of text that conveys information without also using the appropriate markup or text
Additional Techniques (Advisory) for 1.3.4 (REMOVED)
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]
Examples of Success Criterion 1.3.4 (REMOVED)
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.
[end delete]
Understanding Guideline 1.4:
Make it easier for people with disabilities to see and hear content including separating foreground from background
Intent of Guideline 1.4
While some guidelines are focused on making information available in a form that can be presented in alternate formats, this guideline is concerned with making the default presentation as usable as possible to people with disabilities. The primary focus is on making it easier for users to separate foreground information from the background. For visual presentations this involves making sure that information presented on top of a background contrasts sufficiently with the background. For audio presentations this involves making sure that foreground sounds are sufficiently louder than the background sounds. Individuals with visual and hearing disabilities have much greater difficulty separating foreground and background information.
Advisory Techniques for Guideline 1.4 (not success criteria specific)
Specific techniques for meeting each success criterion for this guideline are listed in the understanding 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.
Understanding Success Criterion 1.4.1 (Use of Color)
[begin change] [end change] Key Terms
- information that is conveyed by color [begin add]differences[end add]
information presented in a manner that depends entirely on the ability to perceive color
[begin change]
Intent of this Success Criterion
The intent of this success criterion is to ensure that all users can access information that is conveyed by color differences. If the information is conveyed through color differences in an image (or other non-text format), the color may not be seen by those with color deficiencies. In this case, providing the information conveyed with color through another visual means ensures users who cannot see 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.
Specific Benefits of Success Criterion 1.4.1:
This success criterion benefits people with visual disabilities:
Techniques for Addressing Success Criterion 1.4.1
Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this success criterion. The techniques listed only satisfy the success criterion if all of the WCAG 2.0 conformance requirements have been met.
Sufficient Techniques
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.
Common Failures Identified by the Working Group
The following are common mistakes that are considered failures of Success Criterion 1.4.1 by the WCAG Working Group.
Additional Techniques (Advisory) for 1.4.1
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.
Examples of Success Criterion 1.4.1
A form that uses color and text to indicate required fields
A form contains both required and optional fields. Instructions at the top of the form explain that required fields are labeled with red text and also with an icon whose text alternative says, “Required.” . Both the red text and the icon are programmatically associated with the appropriate form fields so that assistive technology users can determine the required fields.
An examination.
Students view an SVG image of a chemical compound and identify the chemical elements present based on the colors used in the diagram. The text alternatives associated with each element name the color of the element and indicate the element's position in the diagram. Students who cannot perceive color have the same information about the compound as their classmates. (This technique also satisfies Guideline 1.1 Level A.)
Disabled Form elements.
[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]
Related Resources
Resources are for information purposes only, no endorsement implied.
(none currently documented)
Understanding Success Criterion 1.4.2 (Audio Turnoff)
[begin change]
1.4.2
[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 A)
[end change] Key Terms
- mechanism
process or technique for achieving a result
[begin add] 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]
Intent of this Success Criterion
Individuals who use screen reading software can find it hard to understand the speech output if there is other audio playing at the same time. This difficulty is exacerbated when the screen reader's speech output is software based (as most are today) and is controlled via the same volume control as the sound. [begin add]Therefore, it is important that the user be able to turn off the background sound. Note: Having control of the volume includes being able to reduce its volume to zero.[end add]
Specific Benefits of Success Criterion 1.4.2:
Techniques for Addressing Success Criterion 1.4.2
Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this success criterion. The techniques listed only satisfy the success criterion if all of the WCAG 2.0 conformance requirements have been met.
Common Failures Identified by the Working Group
The following are common mistakes that are considered failures of Success Criterion 1.4.2 by the WCAG Working Group.
Additional Techniques (Advisory) for 1.4.2
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.
Examples of Success Criterion 1.4.2
An audio file begins playing automatically when a page is opened. However, the audio can be stopped by the user by selecting a "silent" link at the top of the page.
[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 automatically includes a control at the top that allows users to turn the sound off.
[LC-794]
[end add]
Understanding Success Criterion 1.4.3 (Contrast (Minimum))
[begin change] [end change] Key Terms
- text
[begin delete] Note 1:
[begin add]This definition does not place requirements on the specific encoding of characters. For advice about appropriate character encodings, refer to [I18N-CHAR-ENC].
[LC-849]
[end add]
Note 2:
Characters are those included in the Unicode/ISO/IEC 106464 repertoire.
- contrast ratio
(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:
Contrast ratios can range from 1 to 21 (commonly written 1:1 to 21:1).
Note 2:
For dithered colors, use the average values of the colors that are dithered (average R, average G, and average B).
Note 3:
Text can be evaluated with anti-aliasing turned off.
Note 4:
Background color is the specified color of content over which the text is to be rendered in normal usage. If no background color is specified, then white is assumed.
Note 5:
For text displayed over gradients and background images, authors should ensure that sufficient contrast exists for each part of each character in the content.
- pure decoration
serving only an aesthetic purpose, providing no information, and having no functionality
[begin add] Note: Text is only purely decorative if the words can be rearranged or substituted without changing their purpose.
[begin add] Example: The cover page of a dictionary has random words in very light text in the background.
- larger scale (text)
[begin add] at least 18 point or 14 point bold
[end add] Note 1:
Fonts with extraordinarily thin strokes or unusual features and characteristics that reduce the familiarity of their letter forms are harder to read, especially at lower contrast levels.
Note 2:
Font size is the size when the content is delivered. It does not include resizing that may be done by a user.
[begin change]
Intent of this Success Criterion
The intent of this success criterion is to provide enough contrast between text and its background so that it can be read by people with moderately low vision (who do not use contrast-enhancing assistive technology). For people without color deficiencies, hue and saturation have minimal or no effect on legibility as assessed by reading performance (Knoblauch et al., 1991). Color deficiencies can affect luminance contrast somewhat. However, in the recommendation, the contrast is calculated in such a way that color is not a key factor so that people who have a color vision deficit will also have adequate contrast between the text and the background. Text that is decorative and conveys no information is excluded. For example, if random words are used to create a background and the words could be rearranged or substituted without changing meaning, then it would be decorative and would not need to meet this criterion.
[LC-1161]
Text that is larger and has wider character strokes is easier to read at lower contrast. The contrast requirements for larger text is therefore lower. This allows authors to use a wider range of color choices for large text, which is helpful for design of pages, particularly titles. 18 point text or 14 point bold text is judged to be large enough to require a lower contrast ratio. "18 point" and "bold" can both have different meanings in different fonts but, except for very thin or unusual fonts, they should be sufficient. Since there are so many different fonts, the general measures are used and a note regarding fancy or thin fonts is included.
[begin add] Rationale for the Ratios Chosen
A contrast ratio of 3:1 is the minimum level recommended by [ISO-9241-3] and [ANSI-HFES-100-1988] for standard text and vision. The 5:1 ratio is used in this provision to account for the loss in contrast that results from moderately low visual acuity, congenital or acquired color deficiencies, or the loss of contrast sensitivity that typically accompanies aging.
The rationale is that loss of logarithm of visual acuity is generally linearly related to loss of logarithm of contrast sensitivity, in people with low vision such that the user with 20/40 visual acuity would need roughly 4.5:1 contrast to have the equivalent of the 3:1 minimum contrast standard for normal vision [ARDITI-FAYE]. The user with 20/47 visual acuity would require contrast of about 5:1, and the user with 20/80 visual acuity would require contrast of about 7:1.
Hues are perceived differently by users with color vision deficiencies (both congenital and acquired) resulting in different colors and relative luminance contrasts than for normally sighted users. Because of this, effective contrast and readability are different for this population. However, color deficiencies are so diverse that prescribing effective general use color pairs (for contrast) based on quantitative data is not feasible. Requiring good luminance contrast accommodates this by requiring contrast that is independent of color perception. Fortunately, most of the luminance contribution is from the mid and long wave receptors which largely overlap in their spectral responses. The result is that effective luminance contrast can generally be computed without regard to specific color deficiency, except for the use of predominantly long wavelength colors against darker colors (generally appearing black) for those who have protanopia. (We provide an advisory technique on avoiding red on black for that reason). For more information see [ARDITI-KNOBLAUCH]
[ARDITI-KNOBLAUCH-1996]
[ARDITI].
The contrast ratio of 5:1 was chosen for level AA because it compensated for the loss in contrast sensitivity usually experienced by users with vision loss equivalent to approximately 20/40 vision. (20/40 calculates to approximately 4.5:1 which is rounded up to 5 providing a slight additional increase in contrast.) 20/40 is commonly reported as typical visual acuity of elders at roughly age 80. [GITTINGS-FOZARD]
The contrast ratio of 7:1 was chosen for level AAA because it compensated for the loss in contrast sensitivity usually experienced by users with vision loss equivalent to approximately 20/80 vision. People with more than this degree of vision loss usually use assistive technologies to access their content (and the assistive technologies usually have contrast enhancing, as well as magnification capability built into them). The 7:1 level therefore generally provides compensation for the loss in contrast sensitivity experienced by users with low vision who do not use assistive technology and provides contrast enhancement for color deficiency as well.
[begin add] Notes on formula
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-HFES-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] and the [sRGB] paper by M. Stokes et al.
This success criterion and its definitions use 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]
Specific Benefits of Success Criterion 1.4.3:
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.
Techniques for Addressing Success Criterion 1.4.3
Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this success criterion. The techniques listed only satisfy the success criterion if all of the WCAG 2.0 conformance requirements have been met.
Sufficient Techniques
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.
Common Failures Identified by the Working Group
The following are common mistakes that are considered failures of Success Criterion 1.4.3 by the WCAG Working Group.
Additional Techniques (Advisory) for 1.4.3
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.
Examples of Success Criterion 1.4.3
Related Resources
Resources are for information purposes only, no endorsement implied.
[begin add]
Understanding Success Criterion 1.4.4 (Resize text)
[begin add]
1.4.4 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 AA)
[end add] Key Terms
- Assistive technology ([begin change]as used in this document
[LC-732]
[end change])
a user agent that [begin add]both[end add]:
[begin change] provides services to meet the requirements of users with disabilities that go beyond those offered by the mainstream user agents. Such services include alternative presentations (e.g., as synthesized speech or magnified content), alternative input methods (e.g., voice), additional navigation or orientation mechanisms, and content transformations (e.g., to make tables more accessible)[begin add], and[end add]
[LC-1178]
[end change] usually relies on services (such as retrieving Web content and parsing markup) provided by one or more other mainstream user agents. Assistive technologies communicate data and messages with mainstream user agents by using and monitoring APIs
Note 1:
[begin add]In this definition, user agents are user agents in the general sense of the term. That is, any software that retrieves and [begin change]presents[end change] Web content for users. The mainstream 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]Mainstream 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];
[begin add] 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.
Intent of this Success Criterion
The intent of this success criterion is to ensure that visually rendered text can be scaled successfully so that it can be read directly by people with mild visual disabilities, without requiring the use of assistive technology such as a screen magnifier. Users may benefit from scaling all content on the Web page, but text is most critical.
The scaling of content is primarily a user agent responsibility. User agents that satisfy UAAG 1.0 Checkpoint 4.1 allow users to configure text scale. The author's responsibility is to create web content that does not prevent the user agent from scaling the content effectively. Authors may satisfy this success criterion by verifying that content does not interfere with user agent support for resizing text, or by providing direct support for resizing text or changing the layout. An example of direct support might be via server-side script that can be used to assign different style sheets.
Content satisfies the success criterion if it can be scaled up to 200%, that is, up to twice the width and height. Authors may support scaling beyond that limit, however, as scaling becomes more extreme, adaptive layouts may introduce usability problems. For example, words may be too wide to fit into the horizontal space available to them, causing them to be truncated; layout constraints may cause text to overlap with other content when it is scaled larger; or only one word of a sentence may fit on each line, causing the sentence to be displayed as a vertical column of text that is difficult to read.
The working group feels that 200% is a reasonable accommodation that can support a wide range of designs and layouts, and complements older screen magnifiers that provide a minimum magnification of 200%. Above 200%, zoom (which resizes text, images, and layout regions and creates a larger canvas that may require both horizontal and vertical scrolling) may be more effective than text resizing. Assistive technology dedicated to zoom support would usually be used in such a situation and may provide better accessibility than attempts by the author to support the user directly.
Specific Benefits of Success Criterion 1.4.4:
This success criterion helps people with low vision by letting them increase text size in content so that they can read it.
Techniques for Addressing Success Criterion 1.4.4
Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this success criterion. The techniques listed only satisfy the success criterion if all of the WCAG 2.0 conformance requirements have been met.
Sufficient Techniques
Ensuring that text containers resize when the text resizes AND using measurements that are relative to other measurements in the content by using one or more of the following techniques:
Techniques for relative measurements
Techniques for text container resizing
Calculating size and position in a way that scales with text size (future link) (SCRIPT)
Providing controls on the Web page that incrementally change the size of the text (future link)
Providing options within the content to switch between layouts that use a variety of font sizes (future link)
Common Failures Identified by the Working Group
The following are common mistakes that are considered failures of Success Criterion 1.4.4 by the WCAG Working Group.
Additional Techniques (Advisory) for 1.4.4
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 large fonts by default (future link)
Avoiding the use of text in raster images (future link)
Using page-percent for container sizes (future link)
Avoiding scaling font sizes smaller than the user-agent default (future link)
Note: The author won't actually know the font size, but should avoid percentage scaling that results in less than 100%
Avoiding justified text (future link)
[LC-569]
Providing sufficient inter-line and inter-column spacing (future link)
[LC-569]
Examples of Success Criterion 1.4.4
A user with vision impairments increases the text size on a web page in a browser from 1 em to 1.2 ems. While the user could not read the text at the smaller size, she can read the larger text. All the information on the page is still displayed when the larger font is used for the text.
A Web page contains a control for changing the scale of the page. Selecting different settings changes the layout of the page to use the best design for that scale.
A user uses a zoom function in his user agent to change the scale of the content. All the content scales uniformly, and the user agent provides scroll bars, if necessary.
Related Resources
Resources are for information purposes only, no endorsement implied.
[end add]
Understanding Success Criterion 1.4.5 (Contrast (Enhanced))
Key Terms
- text
[begin delete] Note 1:
[begin add]This definition does not place requirements on the specific encoding of characters. For advice about appropriate character encodings, refer to [I18N-CHAR-ENC].
[LC-849]
[end add]
Note 2:
Characters are those included in the Unicode/ISO/IEC 106464 repertoire.
- contrast ratio
(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:
Contrast ratios can range from 1 to 21 (commonly written 1:1 to 21:1).
Note 2:
For dithered colors, use the average values of the colors that are dithered (average R, average G, and average B).
Note 3:
Text can be evaluated with anti-aliasing turned off.
Note 4:
Background color is the specified color of content over which the text is to be rendered in normal usage. If no background color is specified, then white is assumed.
Note 5:
For text displayed over gradients and background images, authors should ensure that sufficient contrast exists for each part of each character in the content.
- pure decoration
serving only an aesthetic purpose, providing no information, and having no functionality
[begin add] Note: Text is only purely decorative if the words can be rearranged or substituted without changing their purpose.
[begin add] Example: The cover page of a dictionary has random words in very light text in the background.
- larger scale (text)
[begin add] at least 18 point or 14 point bold
[end add] Note 1:
Fonts with extraordinarily thin strokes or unusual features and characteristics that reduce the familiarity of their letter forms are harder to read, especially at lower contrast levels.
Note 2:
Font size is the size when the content is delivered. It does not include resizing that may be done by a user.
[begin change]
Intent of this Success Criterion
The intent of this success criterion is to provide enough contrast between text and its background so that it can be read by people with moderately low vision (who do not use contrast-enhancing assistive technology). For people without color deficiencies, hue and saturation have minimal or no effect on legibility as assessed by reading performance (Knoblauch et al., 1991). Color deficiencies can affect luminance contrast somewhat. However, in the recommendation, the contrast is calculated in such a way that color is not a key factor so that people who have a color vision deficit will also have adequate contrast between the text and the background. Text that is decorative and conveys no information is excluded. For example, if random words are used to create a background and the words could be rearranged or substituted without changing meaning, then it would be decorative and would not need to meet this criterion.
[LC-1161]
Text that is larger and has wider character strokes is easier to read at lower contrast. The contrast requirements for larger text is therefore lower. This allows authors to use a wider range of color choices for large text, which is helpful for design of pages, particularly titles. 18 point text or 14 point bold text is judged to be large enough to require a lower contrast ratio. "18 point" and "bold" can both have different meanings in different fonts but, except for very thin or unusual fonts, they should be sufficient. Since there are so many different fonts, the general measures are used and a note regarding fancy or thin fonts is included.
[begin add] Rationale for the Ratios Chosen
A contrast ratio of 3:1 is the minimum level recommended by [ISO-9241-3] and [ANSI-HFES-100-1988] for standard text and vision. The 5:1 ratio is used in Success Criterion 1.4.3 to account for the loss in contrast that results from moderately low visual acuity, congenital or acquired color deficiencies, or the loss of contrast sensitivity that typically accompanies aging.
The rationale is that loss of logarithm of visual acuity is generally linearly related to loss of logarithm of contrast sensitivity, in people with low vision such that the user with 20/40 visual acuity would need roughly 4.5:1 contrast to have the equivalent of the 3:1 minimum contrast standard for normal vision [ARDITI-FAYE]. The user with 20/47 visual acuity would require contrast of about 5:1, and the user with 20/80 visual acuity would require contrast of about 7:1.
Hues are perceived differently by users with color vision deficiencies (both congenital and acquired) resulting in different colors and relative luminance contrasts than for normally sighted users. Because of this, effective contrast and readability are different for this population. However, color deficiencies are so diverse that prescribing effective general use color pairs (for contrast) based on quantitative data is not feasible. Requiring good luminance contrast accommodates this by requiring contrast that is independent of color perception. Fortunately, most of the luminance contribution is from the mid and long wave receptors which largely overlap in their spectral responses. The result is that effective luminance contrast can generally be computed without regard to specific color deficiency, except for the use of predominantly long wavelength colors against darker colors (generally appearing black) for those who have protanopia. (We provide an advisory technique on avoiding red on black for that reason). For more information see [ARDITI-KNOBLAUCH]
[ARDITI-KNOBLAUCH-1996]
[ARDITI].
The contrast ratio of 5:1 was chosen for level AA because it compensated for the loss in contrast sensitivity usually experienced by users with vision loss equivalent to approximately 20/40 vision. (20/40 calculates to approximately 4.5:1 which is rounded up to 5 providing a slight additional increase in contrast.) 20/40 is commonly reported as typical visual acuity of elders at roughly age 80. [GITTINGS-FOZARD]
The contrast ratio of 7:1 was chosen for level AAA because it compensated for the loss in contrast sensitivity usually experienced by users with vision loss equivalent to approximately 20/80 vision. People with more than this degree of vision loss usually use assistive technologies to access their content (and the assistive technologies usually have contrast enhancing, as well as magnification capability built into them). The 7:1 level therefore generally provides compensation for the loss in contrast sensitivity experienced by users with low vision who do not use assistive technology and provides contrast enhancement for color deficiency as well.
[begin add] Notes on formula
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-HFES-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] and the [sRGB] paper by M. Stokes et al.
This success criterion and its definitions use 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]
Specific Benefits of Success Criterion 1.4.5:
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.
Techniques for Addressing Success Criterion 1.4.5
Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this success criterion. The techniques listed only satisfy the success criterion if all of the WCAG 2.0 conformance requirements have been met.
Sufficient Techniques
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.
Common Failures Identified by the Working Group
The following are common mistakes that are considered failures of Success Criterion 1.4.5 by the WCAG Working Group.
Additional Techniques (Advisory) for 1.4.5
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.
Examples of Success Criterion 1.4.5
Related Resources
Resources are for information purposes only, no endorsement implied.
Understanding Success Criterion 1.4.6 (Low or No Background Audio)
1.4.6 Audio content [begin add]that contains speech in the foreground[end add] 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 AAA)
Note:
[begin delete]A 20 decibel difference in sound level is roughly four times (4x) quieter or louder. [end delete]
[begin change]Background sound that meets this requirement will be approximately one quarter as loud as the foreground speech content.
[LC-743]
[LC-1163]
[end change]
Intent of this Success Criterion
The intent of this success criterion is to ensure that any non-speech sounds are low enough that a user who is hard of hearing can understand the speech. Individuals who are hard of hearing have difficulty separating speech from background sounds or other noise. [begin change]Background sound that meets this requirement will be approximately one quarter as loud as the foreground speech content.
[LC-743]
[end change]
[begin add] 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]
Specific Benefits of Success Criterion 1.4.6:
Techniques for Addressing Success Criterion 1.4.6
Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this success criterion. The techniques listed only satisfy the success criterion if all of the WCAG 2.0 conformance requirements have been met.
Common Failures Identified by the Working Group
The following are common mistakes that are considered failures of Success Criterion 1.4.6 by the WCAG Working Group.
(No failures currently documented)
Additional Techniques (Advisory) for 1.4.6
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.
Examples of Success Criterion 1.4.6
Related Resources
Resources are for information purposes only, no endorsement implied.
[begin add]
Understanding Success Criterion 1.4.7 (Resize and Wrap)
[begin add]
1.4.7 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 AAA)
[end add] Key Terms
- Assistive technology ([begin change]as used in this document
[LC-732]
[end change])
a user agent that [begin add]both[end add]:
[begin change] provides services to meet the requirements of users with disabilities that go beyond those offered by the mainstream user agents. Such services include alternative presentations (e.g., as synthesized speech or magnified content), alternative input methods (e.g., voice), additional navigation or orientation mechanisms, and content transformations (e.g., to make tables more accessible)[begin add], and[end add]
[LC-1178]
[end change] usually relies on services (such as retrieving Web content and parsing markup) provided by one or more other mainstream user agents. Assistive technologies communicate data and messages with mainstream user agents by using and monitoring APIs
Note 1:
[begin add]In this definition, user agents are user agents in the general sense of the term. That is, any software that retrieves and [begin change]presents[end change] Web content for users. The mainstream 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]Mainstream 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];
[begin add] 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.
Intent of this Success Criterion
The intent of this success criterion is to ensure that visually rendered text can be scaled successfully without requiring that the user scroll left and right to see all of the content. When the content has been authored so that this is possible, the content is said to reflow. This permits low vision users to increase the size of the text without becoming disoriented.
The scaling of content is primarily a user agent responsibility. User agents that satisfy UAAG 1.0 Checkpoint 4.1 allow users to configure text scale. The author's responsibility is to create Web content that does not prevent the user agent from scaling the content and that allows the reflow of the content within the current width of the viewport.
Content satisfies the success criterion if it can be scaled up to 200%, that is, up to twice the width and height, although authors may support scaling beyond that limit. However, as scaling becomes more extreme, adaptive layouts may introduce usability problems. For example, words may be too wide to fit into the horizontal space available to them, causing them to be truncated; layout constraints may cause text to overlap with other content when it is scaled larger; or only one word of a sentence may fit on each line, causing the sentence to be displayed as a vertical column of text that is difficult to read.
The working group feels that 200% is a reasonable accommodation that can support a wide range of designs and layouts, and complements older screen magnifiers that provide a minimum magnification of 200%. Above 200%, zoom (which resizes text, images, and layout regions and creates a larger canvas that may require both horizontal and vertical scrolling) may be more effective than text resizing. Assistive technology dedicated to zoom support would usually be used in such a situation and may provide better accessibility than attempts by the author to support the user directly.
It is important to note that horizontal scrolling may be unavoidable for some types of content. For example, content that includes large images may cause user agents to display horizontal scroll bars in where the width of the viewport has been resized to a width that is less than the width of the image.
Specific Benefits of Success Criterion 1.4.7:
This success criterion helps people with low vision by letting them increase text size in content so that they can read it easily. Because there is no need to scroll left and right while reading the text, users are less likely to become disoriented and lose their place.
Techniques for Addressing Success Criterion 1.4.7
Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this success criterion. The techniques listed only satisfy the success criterion if all of the WCAG 2.0 conformance requirements have been met.
Sufficient Techniques
G146: Using liquid layout
AND ensuring that text containers resize when the text resizes AND using measurements that are relative to other measurements in the content by using one or more of the following techniques:
Techniques for relative measurements
Techniques for text container resizing
Calculating size and position in a way that scales with text size (future link) (SCRIPT)
Providing options within the content to switch between layouts that use a variety of font sizes (future link)
Using single-column layouts (future link)
Common Failures Identified by the Working Group
The following are common mistakes that are considered failures of Success Criterion 1.4.7 by the WCAG Working Group.
Additional Techniques (Advisory) for 1.4.7
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 large fonts by default (future link)
Avoiding the use of text in raster images (future link)
Using page-percent for container sizes (future link)
Avoiding scaling font sizes smaller than the user-agent default (future link)
Note: The author won't actually know the font size, but should avoid percentage scaling that results in less than 100%
Avoiding justified text (future link)
[LC-569]
Providing sufficient inter-line and inter-column spacing (future link)
[LC-569]
Examples of Success Criterion 1.4.7
A user with vision impairments increases the text size on a web page in a browser from 10 points to 14 points. While the user could not read the text at the smaller size, she can read the larger text. All the information on the page is still displayed when the larger font is used for the text. While the user may need to scroll up and down to see all of the content, it is not necessary to scroll left or right, that is, all of the content fits between the left and right edges of the viewport.
A Web page contains a control for changing the scale of the page. Selecting different settings changes the layout of the page to use the best design for that scale.
Related Resources
Resources are for information purposes only, no endorsement implied.
[end add]
Understanding Guideline 2.1:
Make all functionality available from a keyboard
Intent of Guideline 2.1
If all functionality can be achieved using the keyboard, it can be accomplished by keyboard users, by speech input (which creates keyboard input), by mouse (using on-screen keyboards), and by a wide variety of assistive technologies that create simulated keystrokes as their output. No other input form has this flexibility or is universally supported and operable by people with different disabilities, as long as the keyboard input is not time-dependent.
Note that providing universal keyboard input does not mean that other types of input should not be supported. Optimized speech input, optimized mouse/pointer input, etc., are also good. The key is to provide keyboard input and control as well.
Some devices do not have native keyboards—for example, a PDA or cell phone. If these devices have a Web browsing capability, however, they will have some means of generating text or "keystrokes." This guideline uses the term "keyboard interface" to acknowledge that Web content should be controlled from keystrokes that may come from a keyboard, keyboard emulator, or other hardware or software that generates keyboard or text input.
Advisory Techniques for Guideline 2.1 (not success criteria specific)
Specific techniques for meeting each success criterion for this guideline are listed in the understanding 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.
- All advisory techniques for this guideline relate to specific success criteria and are listed below.
Understanding Success Criterion 2.1.1 (Keyboard)
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 function[end add] requires [begin add]input that depends on the path of the user's movement and not just the endpoints.[end add]
[begin delete]time-dependent analog input[end delete]
[end change]
[LC-921]
[LC-922]
[LC-1164]
(Level A)
[begin add] Note 1:
This exception relates to the underlying function, not the input technique. For example, if using handwriting to enter text, the input technique (handwriting) requires path dependent input but the underlying function (text input) does not.
[end add] [begin change] Note 2:
This does not forbid and should not discourage providing mouse input or other input methods in addition to keyboard operation.
[end change] Key Terms
- functionality
processes and outcomes achievable through user action
- keyboard interface
interface used by software to obtain keystroke input
Note 1:
Allows users to provide keystroke input to programs even if the native technology does not contain a keyboard.
Example: A touch screen PDA has a keyboard interface built into its operating system as well as a connector for external keyboards. Applications on the PDA can use the interface to obtain keyboard input either from an external keyboard or from other applications that provide simulated keyboard output, such as handwriting interpreters or speech-to-text applications with "keyboard emulation" functionality.
Note 2:
Operation of the application (or parts of the application) through a keyboard-operated mouse emulator, such as MouseKeys, does not qualify as operation through a keyboard interface because operation of the program is through its pointing device interface, not through its keyboard interface.
[begin change]
Intent of this Success Criterion
The intent of this success criterion is to ensure that, wherever possible, content can be operated through a keyboard or keyboard interface (so an alternate keyboard can be used). 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.
[begin add] 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 underlying function requires input that depends on the path of the user's movement and not just the endpoints" is included to separate those things that cannot reasonably be controlled from a keyboard.
[begin add] 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 without requiring an inordinate number of keystrokes. Free hand drawing, watercolor painting, and flying a helicopter through an obstacle course are all examples of functions that require path dependent input. Drawing straight lines, regular geometric shapes, re-sizing windows and dragging objects to a location (when the path to that location is not relevant) do not require path dependent input.
[LC-921]
[LC-922]
[LC-1413]
[end add] [begin add] 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).
[end add]
Specific Benefits of Success Criterion 2.1.1:
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]
Techniques for Addressing Success Criterion 2.1.1
Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this success criterion. The techniques listed only satisfy the success criterion if all of the WCAG 2.0 conformance requirements have been met.
Common Failures Identified by the Working Group
The following are common mistakes that are considered failures of Success Criterion 2.1.1 by the WCAG Working Group.
Additional Techniques (Advisory) for 2.1.1
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)
[begin add] Avoiding use of common user-agent keyboard commands for other purposes (future link)
[LC-726]
[end add]
Examples of Success Criterion 2.1.1
Example 1: A drawing Program.
A drawing program allows users to create, size, position and rotate objects from the keyboard.
Example 2: A drag and Drop Feature.
An application that uses drag and drop also supports "cut" and "paste" or form controls to move objects.
Example 3: Moving between and connecting discrete points.
A connect-the-dots program allows the user to move between dots on a screen and use the spacebar to connect the current dot to the previous one.
Example 4: Exception - Painting Program.
A watercolor painting program passes as an exception because the brush strokes vary depending on the speed and duration of the movements.
Example 5: Exception - Model helicopter flight training simulator.
A model helicopter flight training simulator passes as an exception because the nature of the simulator is to teach real-time behavior of a model helicopter.
Example 6: A PDA with an optional keyboard
A PDA device that is usually operated via a stylus has an optional keyboard that can be attached. The keyboard allows full Web browsing in standard fashion. The Web content is operable because it was designed to work with keyboard-only access.
Understanding Success Criterion 2.1.2 (Keyboard (No Exception))
[begin change] 2.1.2 All functionality of the content is operable through a keyboard interface without requiring specific timings for individual keystrokes. (Level AAA)
[end change] Key Terms
- functionality
processes and outcomes achievable through user action
- keyboard interface
interface used by software to obtain keystroke input
Note 1:
Allows users to provide keystroke input to programs even if the native technology does not contain a keyboard.
Example: A touch screen PDA has a keyboard interface built into its operating system as well as a connector for external keyboards. Applications on the PDA can use the interface to obtain keyboard input either from an external keyboard or from other applications that provide simulated keyboard output, such as handwriting interpreters or speech-to-text applications with "keyboard emulation" functionality.
Note 2:
Operation of the application (or parts of the application) through a keyboard-operated mouse emulator, such as MouseKeys, does not qualify as operation through a keyboard interface because operation of the program is through its pointing device interface, not through its keyboard interface.
Intent of this Success Criterion
The intent of this success criterion is to ensure that all content is operable from the keyboard.This is the same as success criterion 2.1.1, except that no exceptions are allowed. This does not mean that content where the underlying function requires input that depends on the path of the user's movement and not just the endpoints (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 AAA.
Techniques for Addressing Success Criterion 2.1.2
Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this success criterion. The techniques listed only satisfy the success criterion if all of the WCAG 2.0 conformance requirements have been met.
Sufficient Techniques
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 AAA Success Criterion.
Understanding Guideline 2.2:
Provide users with disabilities enough time to read and use content
Intent of Guideline 2.2
Many users who have disabilities need more time to complete tasks than the majority of users: they may take longer to physically respond, they may take longer to read things, they may have low vision and take longer to find things or to read them, or they may be accessing content through an assistive technology that requires more time. This guideline focuses on ensuring that users are able to complete the tasks required by the content with their own individual response times. The primary approaches deal with eliminating time constraints or providing users enough additional time to allow them to complete their tasks. Exceptions are provided for those cases where this is not possible.
Advisory Techniques for Guideline 2.2 (not success criteria specific)
Specific techniques for meeting each success criterion for this guideline are listed in the understanding 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.
- All advisory techniques for this guideline relate to specific success criteria and are listed below.
Understanding Success Criterion 2.2.1 (Timing)
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 A)
Turn off: the user is allowed to turn off the [begin change]time limit[end change]
[begin add]before encountering it; or
[LC-1238]
[end add]
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, [begin delete]competitive gaming or [end delete]time-based testing) and time limits can not be extended further without invalidating the activity.
Key Terms
- activity where timing is essential
activity where timing is part of the design of the activity and removal of the time dependency would change the functionality of the content
Intent of this Success Criterion
The intent of this success criterion is to ensure that users with disabilities are given adequate time to interact with Web content whenever possible. People with disabilities such as blindness, dexterity impairments, and cognitive limitations may require more time to perform functions such as filling out on-line forms. If Web functions are time-dependent, it will be difficult for some users to perform the required action before a [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]
[begin 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] [begin 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]
[end add]
Specific Benefits of Success Criterion 2.2.1:
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.
Techniques for Addressing Success Criterion 2.2.1
Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this success criterion. The techniques listed only satisfy the success criterion if all of the WCAG 2.0 conformance requirements have been met.
Sufficient Techniques
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.
Common Failures Identified by the Working Group
The following are common mistakes that are considered failures of Success Criterion 2.2.1 by the WCAG Working Group.
Additional Techniques (Advisory) for 2.2.1
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.
Examples of Success Criterion 2.2.1
Related Resources
Resources are for information purposes only, no endorsement implied.
(none currently documented)
Understanding Success Criterion 2.2.2 (Blinking)
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 AA)
Note: For requirements related to flickering or flashing content, refer to Guideline 2.3.
Key Terms
- blink
turn on and off between 0.5 and 3 times per second
- Web page
[begin 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.
[begin change] Example 1:
When you enter http://shopping.example.com/ in your browser you enter a movie-like interactive shopping environment where you visually move about a store dragging products off of the shelves around you into a visual shopping cart in front of you. Clicking on a product causes it to be demonstrated with a specification sheet floating alongside.
[end change] Example 2:
A Web resource including all embedded images and media.
[begin add] Example 3:
A Web mail program built using Asynchronous JavaScript and XML (AJAX). The program lives entirely at http://mail.example.com, but includes an inbox, a contacts area and a calendar. Links or buttons are provided that cause the the inbox, contacts, or calendar to display, but do not change the URL of the page as a whole.
[end add] [begin add] Example 4:
A customizable portal site, where users can choose content to display from a set of different content modules.
[end add]
Intent of this Success Criterion
The intent of this success criterion is to avoid distracting users during their interaction with a Web page. Certain groups, particularly those with attention deficit disorders, find blinking content distracting, making it difficult for them to concentrate on other parts of the Web page. Three seconds was chosen because it is long enough to get a user's attention, but not so long that a user can not wait it out if necessary in order to use the page and the blinking blocks their ability to focus on the page.
Specific Benefits of Success Criterion 2.2.2:
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.
Techniques for Addressing Success Criterion 2.2.2
Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this success criterion. The techniques listed only satisfy the success criterion if all of the WCAG 2.0 conformance requirements have been met.
Sufficient Techniques
G11: Creating content that blinks for less than 3 seconds
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:
Common Failures Identified by the Working Group
The following are common mistakes that are considered failures of Success Criterion 2.2.2 by the WCAG Working Group.
Additional Techniques (Advisory) for 2.2.2
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)
Examples of Success Criterion 2.2.2
Example 1: A Web advertisement blinks to get viewers attention but stops after 3 seconds
Example 2: A form blinks an arrow near the submit button if a user finishes filling out the form but does not activate the submit button. The blinking stops after 3 seconds.
Example 3: An animation runs in the upper portion of the page but has a "freeze animation" button near the bottom of the animation.
Related Resources
Resources are for information purposes only, no endorsement implied.
(none currently documented)
Understanding Success Criterion 2.2.3 (Pausing)
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 is essential.[end delete]
[LC-1169]
(Level AA)
Key Terms
- paused
stopped by user request and not restarted until requested by user
- activity where timing is essential
activity where timing is part of the design of the activity and removal of the time dependency would change the functionality of the content
- paused
stopped by user request and not restarted until requested by user
- activity where timing is essential
activity where timing is part of the design of the activity and removal of the time dependency would change the functionality of the content
Intent of this Success Criterion
The intent of this success criterion is to provide an option to temporarily stop content from advancing or updating at a rate beyond the user's ability to read and/or understand the content as it changes.
"Moving" refers to content in which the visible content conveys a sense of motion. Common examples include motion pictures, multimedia presentations, animations, real-time games, and scrolling stock tickers.
"Time-based" refers to content that updates or disappears based on a preset time interval. Common time-based content includes audio, automatically updated weather information, news, stock price updates, and auto-advancing presentations and messages.
Specific Benefits of Success Criterion 2.2.3:
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.
Techniques for Addressing Success Criterion 2.2.3
Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this success criterion. The techniques listed only satisfy the success criterion if all of the WCAG 2.0 conformance requirements have been met.
Common Failures Identified by the Working Group
The following are common mistakes that are considered failures of Success Criterion 2.2.3 by the WCAG Working Group.
Additional Techniques (Advisory) for 2.2.3
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)
Examples of Success Criterion 2.2.3
An essential animation can be paused without effecting the activity
A Web site helps users understand 'how things work' through animations that demonstrate processes. Animations have "pause" and "restart" buttons.
A stock ticker.
[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.
Related Resources
Resources are for information purposes only, no endorsement implied.
(none currently documented)
Understanding Success Criterion 2.2.4 (Timing)
[begin change] 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 AAA)
[end change] Key Terms
- multimedia
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]
- real-time event
event that a) occurs at the same time as the viewing and b) is not completely generated by the content
Example 1:
A Webcast of a live performance [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]
Intent of this Success Criterion
The intent of this success criterion is to minimize the occurrence of content that requires timed interaction. This enables people with blindness, low vision, cognitive limitations, or motor impairments to interact with content. This differs from the Level A success criterion in that the only exception is for real-time events.
Specific Benefits of Success Criterion 2.2.4:
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.
Techniques for Addressing Success Criterion 2.2.4
Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this success criterion. The techniques listed only satisfy the success criterion if all of the WCAG 2.0 conformance requirements have been met.
Common Failures Identified by the Working Group
The following are common mistakes that are considered failures of Success Criterion 2.2.4 by the WCAG Working Group.
(No failures currently documented)
Additional Techniques (Advisory) for 2.2.4
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)
Examples of Success Criterion 2.2.4
A test is designed so that time to complete the test does not effect the scoring
Rather than calibrating an on-line test using a time limit, the test is calibrated based on scores when users have no time limits.
A game is designed so that users take turns rather than competing in real-time
One party can pause the game without invalidating the competitive aspect of it.
Related Resources
Resources are for information purposes only, no endorsement implied.
(none currently documented)
Understanding Success Criterion 2.2.5 (Interruptions)
2.2.5 Interruptions, such as updated content, can be postponed or suppressed by the user, except interruptions involving an emergency. (Level AAA)
Key Terms
- emergency
a sudden, unexpected situation or occurrence that requires immediate action to preserve health, safety, or property
Intent of this Success Criterion
The intent of this success criterion is to allow users to turn off updates from the author/server except in emergencies. Emergencies would include civil emergency alert messages or any other messages that warn of danger to health, safety, or property, including data loss, loss of connection, etcetera.
This allows access by people with cognitive limitations or attention disorders to be able to focus on the content. It also allows users who are blind or have low vision to keep their "viewing" focus on the content they are currently reading.
Specific Benefits of Success Criterion 2.2.5:
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).
Techniques for Addressing Success Criterion 2.2.5
Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this success criterion. The techniques listed only satisfy the success criterion if all of the WCAG 2.0 conformance requirements have been met.
Common Failures Identified by the Working Group
The following are common mistakes that are considered failures of Success Criterion 2.2.5 by the WCAG Working Group.
Additional Techniques (Advisory) for 2.2.5
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)
Examples of Success Criterion 2.2.5
Example 1. Setting user preferences
The preferences page of a Web portal includes an option to postpone all updates and alerts until the end of the current session, except for alerts concerning emergencies.
Related Resources
Resources are for information purposes only, no endorsement implied.
(none currently documented)
Understanding Success Criterion 2.2.6 (Re-authenticating)
2.2.6 When an authenticated session expires, the user can continue the activity without loss of data after re-authenticating. (Level AAA)
Intent of this Success Criterion
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.
Specific Benefits of Success Criterion 2.2.6:
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.
Techniques for Addressing Success Criterion 2.2.6
Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this success criterion. The techniques listed only satisfy the success criterion if all of the WCAG 2.0 conformance requirements have been met.
Sufficient Techniques
Providing options to continue without loss of data using one of the following techniques:
Common Failures Identified by the Working Group
The following are common mistakes that are considered failures of Success Criterion 2.2.6 by the WCAG Working Group.
Additional Techniques (Advisory) for 2.2.6
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)
Examples of Success Criterion 2.2.6
A shopping site checkout
A user with extremely limited use of the hands is logged into a shopping site. It takes so long to enter credit card information into the application that a [begin change]time limit[end change] occurs while the user is performing the checkout process. When the user returns to the checkout process and submits the form, the site returns a login screen to re-authenticate. After the user logs in, the check out process is restored with the same information and at the same stage. The user did not lose any data because the server had temporarily accepted and stored the submission even though the session had timed out and restored the user to the same state after re-authentication was completed.
Authentication in an email program
An email program has an authentication time-out after 30 minutes. The program prompts the user several minutes before the time-out occurs and provides a link to open a new window in order to re-authenticate. The original window with the in-progress email remains intact and, after re-authentication, the user may send that data.
A questionnaire with a [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.
Related Resources
Resources are for information purposes only, no endorsement implied.
(none currently documented)
Understanding Guideline 2.3:
Do not create content that is known to cause seizures
Intent of Guideline 2.3
Some people with seizure disorders can have a seizure triggered by flashing visual content. Most people are unaware that they have this disorder until it strikes. In 1997, a cartoon on television in Japan sent over 700 children to the hospital, including about 500 who had seizures [EPFND]. Warnings do not work well because they are often missed, especially by children who may in fact not be able to read them.
The objective of this guideline is to ensure that content that is marked as conforming to WCAG 2.0 avoids the types of flash that are most likely to cause seizure when viewed even for a second or two.
Advisory Techniques for Guideline 2.3 (not success criteria specific)
Specific techniques for meeting each success criterion for this guideline are listed in the understanding 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.
Understanding Success Criterion 2.3.1 (Three Flashes or Below Threshold)
[begin change] 2.3.1 Content does [begin add]not contain anything that flashes more than three times in any one second period, or the flash is below the general flash and red flash thresholds.
[LC-1187]
[end add]
[begin delete]violate the general flash threshold or the red flash threshold[end delete]
(Level A)
[end change] Key Terms
- general flash and red flash thresholds
a sequence of flashes or rapidly changing image sequences 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 flashes occurring concurrently and contiguously occupies more than a total of .006 steradians (25% of any 10 degree visual field on the screen).
[end add]
For the general flash threshold, a flash is defined as a pair of opposing changes in relative luminance of 10% or more and the relative luminance of the darker image is below 0.80. An "opposing change" is an increase followed by a decrease, or a decrease followed by an increase.
For the red flash threshold, a flash is defined as any transition to or from a saturated red.
[begin change] Note 1:
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 for standard screen sizes and viewing distances.
[begin delete] Note 2:
Based on Wisconsin Computer Equivalence Algorithm for Flash Pattern Analysis (FPA)
[end delete] [begin delete]
[LC-1187]
[end delete]
Intent of this Success Criterion
The intent of this success criterion is to allow users to access the full content of a site without inducing seizures due to photosensitivity.
Individuals who have photosensitive seizure disorders can have a seizure triggered by content that flashes at certain frequencies for more than a few flashes. People are even more sensitive to red flashing than to other colors, so a special test is provided for saturated red flashing. These guidelines are based on guidelines for the broadcasting industry as adapted for computer screens, where content is viewed from a closer distance (using a larger angle of vision).
[begin add] 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 and contiguously means the total area that is actually flashing at the same time. It is calculated by adding up the contiguous area that is flashing simultaneously within any 10 degree angle of view.
Specific Benefits of Success Criterion 2.3.1:
Techniques for Addressing Success Criterion 2.3.1
Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this success criterion. The techniques listed only satisfy the success criterion if all of the WCAG 2.0 conformance requirements have been met.
[begin change]
Sufficient Techniques
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.
[begin add] Situation A: Web content server over the Internet for general viewing
[begin add] Situation B: Web content designed for a specific large-scale display where size and viewing distance is known
Common Failures Identified by the Working Group
The following are common mistakes that are considered failures of Success Criterion 2.3.1 by the WCAG Working Group.
(No failures currently documented)
Additional Techniques (Advisory) for 2.3.1
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)
[begin add] Providing a mechanism to suppress any flashing content before it begins (future link)
[LC-1099]
[end add]
Examples of Success Criterion 2.3.1
[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]
Related Resources
Resources are for information purposes only, no endorsement implied.
Understanding Success Criterion 2.3.2 (Three Flashes)
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 AAA)
[begin change]
Intent of this Success Criterion
The intent of this success criterion is to allow users to access the full content of a site without inducing seizures due to photosensitivity.
Success Criterion 2.3.1 requires that flashing content be less than three flashes in any 1-second period unless it is smaller than 25% 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 25% of a persons central vision.
This success criterion (2.3.2) 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.
Specific Benefits of Success Criterion 2.3.2:
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.
Techniques for Addressing Success Criterion 2.3.2
Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this success criterion. The techniques listed only satisfy the success criterion if all of the WCAG 2.0 conformance requirements have been met.
Common Failures Identified by the Working Group
The following are common mistakes that are considered failures of Success Criterion 2.3.2 by the WCAG Working Group.
(No failures currently documented)
Additional Techniques (Advisory) for 2.3.2
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)
Examples of Success Criterion 2.3.2
Related Resources
Resources are for information purposes only, no endorsement implied.
Understanding Guideline 2.4:
Provide ways to help users with disabilities navigate, find content and determine where they are
Intent of Guideline 2.4
The intent of this guideline is to help users find the content they need and allow them to keep track of their location. These tasks are often more difficult for people with disabilities. For finding, navigation, and orientation, it is important that the user can find out what the current location is. For navigation, information about the possible destinations needs to be available. Screen readers convert content to synthetic speech which, because it is audio, must be presented in linear order. Some success criteria in this guideline explain what provisions need to be taken to ensure that screen reader users can successfully navigate the content. Others allow users to more easily recognize navigation bars and page headers and to bypass this repeated content. [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]
Advisory Techniques for Guideline 2.4 (not success criteria specific)
Specific techniques for meeting each success criterion for this guideline are listed in the understanding 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.
Understanding Success Criterion 2.4.1 (Bypass Blocks)
2.4.1 A mechanism is available to bypass blocks of content that are repeated on multiple Web pages. (Level A)
Key Terms
- Web page
[begin 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.
[begin change] Example 1:
When you enter http://shopping.example.com/ in your browser you enter a movie-like interactive shopping environment where you visually move about a store dragging products off of the shelves around you into a visual shopping cart in front of you. Clicking on a product causes it to be demonstrated with a specification sheet floating alongside.
[end change] Example 2:
A Web resource including all embedded images and media.
[begin add] Example 3:
A Web mail program built using Asynchronous JavaScript and XML (AJAX). The program lives entirely at http://mail.example.com, but includes an inbox, a contacts area and a calendar. Links or buttons are provided that cause the the inbox, contacts, or calendar to display, but do not change the URL of the page as a whole.
[end add] [begin add] Example 4:
A customizable portal site, where users can choose content to display from a set of different content modules.
[end add]
Intent of this Success Criterion
The intent of this success criterion is to allow people who navigate sequentially through content more direct access to the primary content of the Web page. Web pages and applications often have content that appears on other pages or screens. Examples of repeated blocks of content include but are not limited to navigation links, heading graphics, and advertising frames.
This is in contrast to a sighted user's ability to ignore the repeated material either by focusing on the center of the screen (where main content usually appears) or a mouse user's ability to select a link with a single mouse click rather than encountering every link or form control that comes before the item they want.
Specific Benefits of Success Criterion 2.4.1:
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
Techniques for Addressing Success Criterion 2.4.1
Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this success criterion. The techniques listed only satisfy the success criterion if all of the WCAG 2.0 conformance requirements have been met.
Sufficient Techniques
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:
Common Failures Identified by the Working Group
The following are common mistakes that are considered failures of Success Criterion 2.4.1 by the WCAG Working Group.
(No failures currently documented)
Additional Techniques (Advisory) for 2.4.1
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.
Examples of Success Criterion 2.4.1
A news organization's home page contains a main story in the middle of the page, surrounded by many blocks and sidebars for advertising, searching, and other services. There is a link at the top of the page that jumps to the main story. Without using this link, a keyboard user needs to tab through approximately 40 links to reach the main story; the screen reader user has to listen to 200 words; and the screen magnifier user must search around for the location of the main body.
Related Resources
Resources are for information purposes only, no endorsement implied.
(none currently documented)
Understanding Success Criterion 2.4.2 (Page Titled)
[begin change] [end change] Key Terms
- Web page
[begin 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.
[begin change] Example 1:
When you enter http://shopping.example.com/ in your browser you enter a movie-like interactive shopping environment where you visually move about a store dragging products off of the shelves around you into a visual shopping cart in front of you. Clicking on a product causes it to be demonstrated with a specification sheet floating alongside.
[end change] Example 2:
A Web resource including all embedded images and media.
[begin add] Example 3:
A Web mail program built using Asynchronous JavaScript and XML (AJAX). The program lives entirely at http://mail.example.com, but includes an inbox, a contacts area and a calendar. Links or buttons are provided that cause the the inbox, contacts, or calendar to display, but do not change the URL of the page as a whole.
[end add] [begin add] Example 4:
A customizable portal site, where users can choose content to display from a set of different content modules.
[end add]
Intent of this Success Criterion
The intent of this success criterion is to help users find content and orient themselves within it by ensuring that each Web page has a [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]
Specific Benefits of Success Criterion 2.4.2:
[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]
[begin delete] 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]
Techniques for Addressing Success Criterion 2.4.2
Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this success criterion. The techniques listed only satisfy the success criterion if all of the WCAG 2.0 conformance requirements have been met.
Common Failures Identified by the Working Group
The following are common mistakes that are considered failures of Success Criterion 2.4.2 by the WCAG Working Group.
Additional Techniques (Advisory) for 2.4.2
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.
Examples of Success Criterion 2.4.2
A document.
The title of Web Content Accessibility Guidelines 2.0 is "Web Content Accessibility Guidelines 2.0."
The introduction has the title "Introduction to Web Content Accessibility Guidelines 2.0."
The main body has the title "WCAG 2.0 Guidelines."
Appendix A has the title "Glossary to Web Content Accessibility Guidelines 2.0."
Appendix B has the title "Checklist for Web Content Accessibility Guidelines 2.0."
Appendix C has the title "Acknowledgements for Web Content Accessibility Guidelines 2.0."
Appendix D has the title "References for Web Content Accessibility Guidelines 2.0."
[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]
Related Resources
Resources are for information purposes only, no endorsement implied.
Understanding Success Criterion 2.4.3 (Focus Order)
[begin change]
[begin change] 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 A)
[end change] [end change] Key Terms
- Web page
[begin 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.
[begin change] Example 1:
When you enter http://shopping.example.com/ in your browser you enter a movie-like interactive shopping environment where you visually move about a store dragging products off of the shelves around you into a visual shopping cart in front of you. Clicking on a product causes it to be demonstrated with a specification sheet floating alongside.
[end change] Example 2:
A Web resource including all embedded images and media.
[begin add] Example 3:
A Web mail program built using Asynchronous JavaScript and XML (AJAX). The program lives entirely at http://mail.example.com, but includes an inbox, a contacts area and a calendar. Links or buttons are provided that cause the the inbox, contacts, or calendar to display, but do not change the URL of the page as a whole.
[end add] [begin add] Example 4:
A customizable portal site, where users can choose content to display from a set of different content modules.
[end add] - navigated sequentially
navigated in the order defined for advancing focus from one element to the next with the keyboard
[LC-974]
- presentation
[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]
Intent of this Success Criterion
The intent of this success criterion is to ensure that when users navigate sequentially through content, they encounter information in an order that reflects the logical relationships in the content. This reduces confusion by letting users form a consistent mental model of the content. [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]
[begin change] 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] [begin add] 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]
[end add]
Specific Benefits of Success Criterion 2.4.3:
Techniques for Addressing Success Criterion 2.4.3
Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this success criterion. The techniques listed only satisfy the success criterion if all of the WCAG 2.0 conformance requirements have been met.
Common Failures Identified by the Working Group
The following are common mistakes that are considered failures of Success Criterion 2.4.3 by the WCAG Working Group.
Additional Techniques (Advisory) for 2.4.3
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)
Examples of Success Criterion 2.4.3
[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]
Related Resources
Resources are for information purposes only, no endorsement implied.
(none currently documented)
Understanding Success Criterion 2.4.4 (Link Purpose (Context))
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 A)
Editorial Note: There is debate about whether pages that fail this success criterion in fact present a problem for assistive technology. The status of this item as a Level A success criterion is therefore "at risk" as a Level A success criterion depending on AT support and relative need for this provision.
Key Terms
- programmatically determined link context
additional information that can be programmatically determined from relationships with a link[begin change], combined with the link text, and presented to users in different modalities[end change]
[begin delete] 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.
[end delete] [begin change] Example 1:
In HTML, information that is programmatically determinable from a link in English includes 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.
Example 2:
A screen reader provides commands to read the current sentence when focus is on a link in that sentence.
[LC-497]
Intent of this Success Criterion
[begin change] 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] [begin add] 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 itself. 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] [begin 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] [begin 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.
Specific Benefits of Success Criterion 2.4.4:
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]
Techniques for Addressing Success Criterion 2.4.4
Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this success criterion. The techniques listed only satisfy the success criterion if all of the WCAG 2.0 conformance requirements have been met.
Common Failures Identified by the Working Group
The following are common mistakes that are considered failures of Success Criterion 2.4.4 by the WCAG Working Group.
Additional Techniques (Advisory) for 2.4.4
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.
Examples of Success Criterion 2.4.4
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]
Related Resources
Resources are for information purposes only, no endorsement implied.
Understanding Success Criterion 2.4.5 (Multiple Ways)
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 AA)
Key Terms
- set of Web pages
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.
- process
series of user actions where each action is required in order to complete an activity
[begin change] Example 1:
Successful use of a series of Web pages on a shopping site requires users to view alternative products, prices and offers, select products, submit an order, provide shipping information and provide payment information.
[end change] Example 2:
An account registration page requires successful completion of a Turing test before the registration form can be accessed.
Intent of this Success Criterion
The intent of this success criterion is to make it possible for users to locate content in a manner that best meets their needs. Users may find one technique easier or more comprehensible to use than another.
Specific Benefits of Success Criterion 2.4.5:
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.
Techniques for Addressing Success Criterion 2.4.5
Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this success criterion. The techniques listed only satisfy the success criterion if all of the WCAG 2.0 conformance requirements have been met.
Sufficient Techniques
Using two or more of the following techniques:
Common Failures Identified by the Working Group
The following are common mistakes that are considered failures of Success Criterion 2.4.5 by the WCAG Working Group.
(No failures currently documented)
Additional Techniques (Advisory) for 2.4.5
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.
Examples of Success Criterion 2.4.5
A search mechanism.
A large food processing company provides a site containing recipes created using its products. The site provides a search mechanism to search for recipes using a particular ingredient. In addition, it provides a list box that lists several categories of foods. A user may type "soup" in to the search engine or may select "soup" from the list box to go to a page with a list of recipes made from the company's soup products
Links between Web pages.
A local hair salon has created a Web site to promote its services. The site contains only five Web pages. There are links on each Web page to sequentially move forward or backward through the Web pages. In addition, each Web page contains a list of links to reach each of the other Web pages.
Where content is a result of a process or task - Funds transfer confirmation.
An on-line banking site allows fund transfer between accounts via the Web. There is no other way to locate the confirmation of fund transfer until the account owner completes the transfer.
Where content is a result of a process or task - Search engine results.
A search engine provides the search results based on user input. There is no other way to locate the search results except to perform the search process itself.
Related Resources
Resources are for information purposes only, no endorsement implied.
(none currently documented)
Understanding Success Criterion 2.4.6 (Labels Descriptive)
[begin change] [end change] Key Terms
- label
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
Note:
[begin add]See also name.
[LC-847]
[end add]
Intent of this Success Criterion
The intent of this success criterion is to help users understand what information is contained in Web pages and how that information is organized. When [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]
Specific Benefits of Success Criterion 2.4.6:
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]
Techniques for Addressing Success Criterion 2.4.6
Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this success criterion. The techniques listed only satisfy the success criterion if all of the WCAG 2.0 conformance requirements have been met.
Common Failures Identified by the Working Group
The following are common mistakes that are considered failures of Success Criterion 2.4.6 by the WCAG Working Group.
(No failures currently documented)
Additional Techniques (Advisory) for 2.4.6
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.
Examples of Success Criterion 2.4.6
A news site.
The home page of a news site lists the headlines for the top stories of the hour. Under each heading are the first 35 words of the story and a link to the full article. Each headline gives a clear idea of the article's subject.
A guide on how to write well
A guide on writing contains the following section titles: How To Write Well, Cut Out Useless Words, Identify Unnecessary Words, etc. The section headings are clear and concise and the structure of the information is reflected in the structure of the headings.
Example 3: Consistent headings in different articles
A Web site contains papers from a conference. Submissions to the conference are required to have the following organization: Summary, Introduction, [other sections unique to this article], Conclusion, Author Biography, Glossary, and Bibliography. The title of each Web page clearly identifies the article it contains, creating a useful balance between the uniqueness of the articles and the consistency of the section headings.
Related Resources
Resources are for information purposes only, no endorsement implied.
Understanding Success Criterion 2.4.7 (Location)
Key Terms
- set of Web pages
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.
Intent of this Success Criterion
The intent of this success criterion is to provide a way for the user to orient herself within a set of Web pages, a Web site, or a Web application and find related information.
Specific Benefits of Success Criterion 2.4.7:
Techniques for Addressing Success Criterion 2.4.7
Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this success criterion. The techniques listed only satisfy the success criterion if all of the WCAG 2.0 conformance requirements have been met.
Common Failures Identified by the Working Group
The following are common mistakes that are considered failures of Success Criterion 2.4.7 by the WCAG Working Group.
(No failures currently documented)
Additional Techniques (Advisory) for 2.4.7
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.
Examples of Success Criterion 2.4.7
Links to help user determine their location in a site
A research group is part of an educational department at a university. The group's home page links to the department home page and the university's home page.
A breadcrumb trail
A portal Web site organizes topics into categories. As the user navigates through categories and subcategories, a breadcrumb trail shows the current location in the hierarchy of categories. Each page also contains a link to the portal home page.
Related Resources
Resources are for information purposes only, no endorsement implied.
Understanding Success Criteri