if removed, would fundamentally change the information or functionality of the content,
5 | and information and functionality cannot be achieved in another way that would conform
6 |
information and sensory experience to be communicated to the user by means of a user agent, including code or markup that defines the content's structure, presentation, and interactions
6 |
audio or video synchronized with another format for presenting information and/or with time-based
5 | interactive components, unless the media is a media alternative for text that is clearly labeled as such
6 |
pointer input that operates with one point of contact with the screen, including single taps and clicks, double-taps and clicks, long presses, and path-based gestures
A mechanism is available for identifying specific pronunciation of words where meaning of the
8 | words, in context, is ambiguous without knowing the pronunciation.
9 |
Changing the setting of any user interface component does not automatically cause a change of context unless the user has been advised of the behavior before using the component.
8 |
If a Web page can be navigated sequentially and the navigation sequences affect meaning or operation, focusable components receive
8 | focus in an order that preserves meaning and operability.
9 |
switch back and forth between two visual states in a way that is meant to draw attention
5 |
6 |
See also flash. It is possible for something to be large enough and blink brightly enough at the
7 | right frequency to be also classified as a flash.
8 |
A mechanism is available to allow the purpose of each link to be identified from link text alone,
8 | except where the purpose of the link would be ambiguous to users in general.
9 |
any software that retrieves and presents Web content for users
5 |
6 |
Web browsers, media players, plug-ins, and other programs — including assistive technologies — that help in retrieving, rendering, and interacting with Web content.
7 |
Navigational mechanisms that are repeated on multiple Web pages within a set of Web pages occur in the same relative order each time they are repeated, unless a change is initiated by the user.
8 |
If an input error is automatically detected and suggestions for correction are known, then the suggestions
8 | are provided to the user, unless it would jeopardize the security or purpose of the
9 | content.
10 |
Status messages are programmatically determined through role or attributes such that they can be presented to the user by assistive technologies without receiving focus.
Web content does not restrict use of input modalities available on a platform except where the restriction is essential, required to ensure the security of the content, or required to respect user settings.
change in content that is not a change of context, and that provides information to the user on the success or results of an action, on the waiting state of an application, on the progress of a process, or on the existence of errors
7 |
8 |
9 |
--------------------------------------------------------------------------------
/README.md:
--------------------------------------------------------------------------------
1 | # wcag21
2 | [WCAG 2.1](https://www.w3.org/TR/WCAG21/) was published as a W3C Recommendation June 2018.
3 |
4 | This repository was used to develop content for WCAG 2.1, as well as associated understanding documents and techniques. **It is no longer in use** and this repository is merely an archive.
5 |
6 | Work on new versions of WCAG, as well as support material for all versions of WCAG, now takes place in the [wcag repository](https://github.com/w3c/wcag).
--------------------------------------------------------------------------------
/guidelines/sc/20/link-purpose-in-context.html:
--------------------------------------------------------------------------------
1 |
2 |
3 |
the two or three year period of education that begins after completion of six years
5 | of school and ends nine years after the beginning of primary education
6 |
7 |
This definition is based on the International Standard Classification of Education
8 | [[UNESCO]].
9 |
When text requires reading ability more advanced than the lower secondary education level after removal of proper names and titles, supplemental content, or a version that does not require reading ability more advanced than the lower
8 | secondary education level, is available.
9 |
text by which software can identify a component within Web content to the user
5 |
6 |
The name may be hidden and only exposed by assistive technology, whereas a label is presented to all users. In many (but not all) cases, the label and the name are
7 | the same.
8 |
The human language of each passage or phrase in the content can be programmatically determined except for proper names, technical terms, words of indeterminate language, and words
8 | or phrases that have become part of the vernacular of the immediately surrounding
9 | text.
10 |
This includes ASCII Art (which is a pattern of characters), emoticons, leetspeak (which uses character substitution),
7 | and images representing text
8 |
A submit "search" button on one Web page and a "find" button on another Web page may
7 | both have a field to enter a term and list topics in the Web site related to the term
8 | submitted. In this case, they would have the same functionality but would not be labeled
9 | consistently.
10 |
audio description that is added to an audiovisual presentation by pausing the video so that there is time to add additional description
5 |
6 |
7 |
This technique is only used when the sense of the video would be lost without the additional audio description and the pauses between dialogue/narration are too short.
8 |
Items are considered to be in the same relative order even if other items are inserted
7 | or removed from the original order. For example, expanding navigation menus may insert
8 | an additional level of detail or a secondary navigation section may be inserted into
9 | the reading order.
10 |
on the most common sized desktop/laptop display with the viewport maximized
5 |
6 |
Since people generally keep their computers for several years, it is best not to rely
7 | on the latest desktop/laptop display resolutions but to consider the common desktop/laptop
8 | display resolutions over the course of several years when making this evaluation.
9 |
region of the display that will accept a pointer action, such as the interactive area of a user interface component
7 |
If two or more touch targets are overlapping, the overlapping area should not be included in the measurement of the target size, except when the overlapping targets perform the same action or open the same page.
media that presents no more information than is already presented in text (directly
5 | or via text alternatives)
6 |
7 |
8 |
A media alternative for text is provided for those who benefit from alternate representations
9 | of text. Media alternatives for text may be audio-only, video-only (including sign-language
10 | video), or audio-video.
11 |
Instructions provided for understanding and operating content do not rely solely on
8 | sensory characteristics of components such as shape, color, size, visual location, orientation,
9 | or sound.
10 |
11 |
12 |
For requirements related to color, refer to Guideline 1.4.
dynamic property expressing characteristics of a user interface component that may change in response to user action or automated processes
7 |
States do not affect the nature of the component, but represent data associated with the component or user interaction possibilities. Examples include focus, hover, select, press, check, visited/unvisited, and expand/collapse.
text or other component with a text alternative that is presented to a user to identify a component within Web content
5 |
6 |
A label is presented to all users whereas the name may be hidden and only exposed by assistive technology. In many (but not all) cases
7 | the name and the label are the same.
8 |
9 |
10 |
The term label is not limited to the label element in HTML.
information captured from a real-world event and transmitted to the receiver with
5 | no more than a broadcast delay
6 |
7 |
8 |
A broadcast delay is a short (usually automated) delay, for example used in order
9 | to give the broadcaster time to cue or censor the audio (or video) feed, but not sufficient
10 | to allow significant editing.
11 |
12 |
13 |
If information is completely computer generated, it is not live.
Color is not used as the only visual means of conveying information, indicating an
8 | action, prompting a response, or distinguishing a visual element.
9 |
10 |
11 |
This success criterion addresses color perception specifically. Other forms of perception are covered in Guideline 1.3 including programmatic access to color and other visual presentation coding.
addition of steps between conditions to create the illusion of movement or to give a sense of a smooth transition
7 |
For example, an element which moves into place or changes size while appearing is considered to be animated. An element which appears instantly without transitioning is not using animation. Motion animation does not include changes of color, blurring or opacity.
document including correctly sequenced text descriptions of time-based visual and
5 | auditory information and providing a means for achieving the outcomes of any time-based
6 | interaction
7 |
8 |
9 |
A screenplay used to create the synchronized media content would meet this definition
10 | only if it was corrected to accurately represent the final synchronized media after
11 | editing.
12 |
initialism for "Completely Automated Public Turing test to tell Computers and Humans
5 | Apart"
6 |
7 |
8 |
CAPTCHA tests often involve asking the user to type in text that is displayed in an
9 | obscured image or audio file.
10 |
11 |
12 |
A Turing test is any system of tests designed to differentiate a human from a computer.
13 | It is named after famed computer scientist Alan Turing. The term was coined by researchers
14 | at Carnegie Mellon University.
15 |
series of user actions where each action is required in order to complete an activity
5 |
6 |
Successful use of a series of Web pages on a shopping site requires users to view
7 | alternative products, prices and offers, select products, submit an order, provide
8 | shipping information and provide payment information.
9 |
10 |
11 |
An account registration page requires successful completion of a Turing test before
12 | the registration form can be accessed.
13 |
Content does not restrict its view and operation to a single display orientation, such as portrait or landscape, unless a specific display orientation is essential.
10 |
11 |
Examples where a particular display orientation may be essential are a bank check, a piano application, slides for a projector or television, or virtual reality content where binary display orientation is not applicable.
All functionality that uses multipoint or path-based gestures for operation can be operated with a single pointer without a path-based gesture, unless a multipoint or path-based gesture is essential.
10 |
11 |
This requirement applies to web content that interprets pointer actions (i.e. this does not apply to actions that are required to operate the user agent or assistive technology).
In content implemented using markup languages, elements have complete start and end
8 | tags, elements are nested according to their specifications, elements do not contain
9 | duplicate attributes, and any IDs are unique, except where the specifications allow
10 | these features.
11 |
12 |
13 |
Start and end tags that are missing a critical character in their formation, such
14 | as a closing angle bracket or a mismatched attribute value quotation mark are not
15 | complete.
16 |
words used in such a way that requires users to know exactly which definition to apply
5 | in order to understand the content correctly
6 |
7 |
8 |
The term "gig" means something different if it occurs in a discussion of music concerts
9 | than it does in article about computer hard drive space, but the appropriate definition
10 | can be determined from context. By contrast, the word "text" is used in a very specific
11 | way in WCAG 2.1, so a definition is supplied in the glossary.
12 |
collection of web pages that share a common purpose and that are created by the same author, group or organization
5 |
6 |
7 |
Examples include a publication which is split across multiple Web pages, where each page contains
8 | one chapter or other significant section of the work. The publication is logically
9 | a single contiguous unit, and contains navigation features that enable access to the
10 | full set of pages.
11 |
12 |
13 |
Different language versions would be considered different sets of Web pages.
The user agent presents content through one or more viewports. Viewports include windows, frames,
7 | loudspeakers, and virtual magnifying glasses. A viewport may contain another viewport
8 | (e.g., nested frames). Interface components created by the user agent such as prompts,
9 | menus, and alerts are not viewports.
10 |
event that a) occurs at the same time as the viewing and b) is not completely generated
5 | by the content
6 |
7 |
8 |
A Webcast of a live performance (occurs at the same time as the viewing and is not
9 | prerecorded).
10 |
11 |
12 |
An on-line auction with people bidding (occurs at the same time as the viewing).
13 |
14 |
Live humans interacting in a virtual world using avatars (is not completely generated
15 | by the content and occurs at the same time as the viewing).
16 |
Since any content that does not meet this success criterion can interfere with a user's
12 | ability to use the whole page, all content on the Web page (whether it is used to
13 | meet other success criteria or not) must meet this success criterion. See Conformance Requirement 5: Non-Interference.
14 |
If any audio on a Web page plays automatically for more than 3 seconds, either a mechanism is available to pause or stop the audio, or a mechanism is available to control audio
8 | volume independently from the overall system volume level.
9 |
10 |
11 |
Since any content that does not meet this success criterion can interfere with a user's
12 | ability to use the whole page, all content on the Web page (whether or not it is used
13 | to meet other success criteria) must meet this success criterion. See Conformance Requirement 5: Non-Interference.
14 |
Text that is programmatically associated with non-text content or referred to from text that is programmatically associated with non-text content.
5 | Programmatically associated text is text whose location can be programmatically determined
6 | from the non-text content.
7 |
8 |
9 |
An image of a chart is described in text in the paragraph after the chart. The short
10 | text alternative for the chart indicates that a description follows.
11 |
Functionality that can be operated by device motion or user motion can also be operated by user interface components and responding to the motion can be disabled to prevent accidental actuation, except when:
the purpose cannot be determined from the link and all information of the Web page
5 | presented to the user simultaneously with the link (i.e., readers without disabilities
6 | would not know what a link would do until they activated it)
7 |
8 |
9 |
The word guava in the following sentence "One of the notable exports is guava" is
10 | a link. The link could lead to a definition of guava, a chart listing the quantity
11 | of guava exported or a photograph of people harvesting guava. Until the link is activated,
12 | all readers are unsure and the person with a disability is not at any disadvantage.
13 |
Users are warned of the duration of any user inactivity that could cause data loss, unless the data is preserved for more than 20 hours when the user does not take any actions.
10 |
11 |
Privacy regulations may require explicit user consent before user identification has been authenticated and before user data is preserved. In cases where the user is a minor, explicit consent may not be solicited in most jurisdictions, countries or regions. Consultation with privacy professionals and legal counsel is advised when considering data preservation as an approach to satisfy this success criterion.
additional information that can be programmatically determined from relationships with a link, combined with the link text, and presented to users in different modalities
5 |
6 |
7 |
In HTML, information that is programmatically determinable from a link in English
8 | includes text that is in the same paragraph, list, or table cell as the link or in
9 | a table header cell that is associated with the table cell that contains the link.
10 |
11 |
12 |
Since screen readers interpret punctuation, they can also provide the context from
13 | the current sentence, when the focus is on a link in that sentence.
14 |
A CSS pixel is the canonical unit of measure for all lengths and measurements in CSS.
9 | This unit is density-independent, and distinct from actual hardware pixels present
10 | in a display. User agents and operating systems should ensure that a CSS pixel is
11 | set as closely as possible to the CSS Values and Units Module Level 3 reference pixel [[!css3-values]], which takes into account the physical dimensions of the display
12 | and the assumed viewing distance (factors that cannot be determined by content authors).
13 |
For Web pages that cause legal commitments or financial transactions for the user to occur, that modify or delete user-controllable data in data storage systems, or that submit user test responses, at least one of
8 | the following is true:
9 |
10 |
11 |
12 |
Reversible
Submissions are reversible.
13 |
Checked
Data entered by the user is checked for input errors and the user is provided an opportunity to correct them.
14 |
Confirmed
A mechanism is available for reviewing, confirming, and correcting information before finalizing the submission.
This success criterion is primarily for Web authors who develop or script their own
12 | user interface components. For example, standard HTML controls already meet this success
13 | criterion when used according to specification.
14 |
If keyboard focus can be moved to a component of the page using a keyboard interface, then focus can be moved away from that component using only a keyboard interface,
8 | and, if it requires more than unmodified arrow or tab keys or other standard exit
9 | methods, the user is advised of the method for moving focus away.
10 |
11 |
12 |
Since any content that does not meet this success criterion can interfere with a user's
13 | ability to use the whole page, all content on the Web page (whether it is used to
14 | meet other success criteria or not) must meet this success criterion. See Conformance Requirement 5: Non-Interference.
15 |
determined by software from author-supplied data provided in a way that different
6 | user agents, including assistive technologies, can extract and present this information to users in different modalities
7 |
8 |
9 |
Determined in a markup language from elements and attributes that are accessed directly
10 | by commonly available assistive technology.
11 |
12 |
13 |
Determined from technology-specific data structures in a non-markup language and exposed
14 | to assistive technology via an accessibility API that is supported by commonly available
15 | assistive technology.
16 |
If a keyboard shortcut is implemented in content using only letter (including upper- and lower-case letters), punctuation, number, or symbol characters, then at least one of the following is true:
10 |
11 |
12 |
13 |
Turn off
14 |
A mechanism is available to turn the shortcut off;
15 |
16 |
Remap
17 |
A mechanism is available to remap the shortcut to use one or more non-printable keyboard characters (e.g. Ctrl, Alt, etc);
18 |
19 |
Active only on focus
20 |
The keyboard shortcut for a user interface component is only active when that component has focus.
All functionality of the content is operable through a keyboard interface without requiring specific timings for individual keystrokes, except where the underlying
8 | function requires input that depends on the path of the user's movement and not just
9 | the endpoints.
10 |
11 |
12 |
This exception relates to the underlying function, not the input technique. For example,
13 | if using handwriting to enter text, the input technique (handwriting) requires path-dependent
14 | input but the underlying function (text input) does not.
15 |
16 |
17 |
This does not forbid and should not discourage providing mouse input or other input
18 | methods in addition to keyboard operation.
19 |
For the visual presentation of blocks of text, a mechanism is available to achieve the following:
8 |
9 |
10 |
Foreground and background colors can be selected by the user.
11 |
Width is no more than 80 characters or glyphs (40 if CJK).
12 |
Text is not justified (aligned to both the left and the right margins).
13 |
Line spacing (leading) is at least space-and-a-half within paragraphs, and paragraph spacing is at least 1.5 times larger than the line spacing.
14 |
Text can be resized without assistive technology up to 200 percent in a way that does not require the user to scroll horizontally to read a line of text on a full-screen window.
If the technologies being used can achieve the visual presentation, text is used to convey information rather than images of text except for the following:
8 |
9 |
10 |
11 |
12 |
Customizable
13 |
14 |
15 |
16 |
The image of text can be visually customized to the user's requirements;
17 |
18 |
19 |
20 |
21 |
Essential
22 |
23 |
24 |
25 |
A particular presentation of text is essential to the information being conveyed.
26 |
27 |
28 |
29 |
30 |
31 |
32 |
Logotypes (text that is part of a logo or brand name) are considered essential.
mechanism for encoding instructions to be rendered, played or executed by user agents
6 |
7 |
As used in these guidelines "Web Technology" and the word "technology" (when used
8 | alone) both refer to Web Content Technologies.
9 |
10 |
11 |
Web content technologies may include markup languages, data formats, or programming
12 | languages that authors may use alone or in combination to create end-user experiences
13 | that range from static Web pages to synchronized media presentations to dynamic Web
14 | applications.
15 |
16 |
17 |
Some common examples of Web content technologies include HTML, CSS, SVG, PNG, PDF,
18 | Flash, and JavaScript.
19 |
property whose value determines the presentation (e.g. font, color, size, location, padding, volume, synthesized speech prosody) of
5 | content elements as they are rendered (e.g. onscreen, via loudspeaker, via braille display) by user agents
6 |
Style properties can have several origins:
7 |
8 |
User agent default styles: The default style property values applied in the absence of any author or user styles. Some web content technologies specify a default rendering, others do not;
9 |
Author styles: Style property values that are set by the author as part of the content (e.g. in-line styles, author style
10 | sheets);
11 |
User styles: Style property values that are set by the user (e.g. via user agent interface settings, user style sheets)
The visual presentation of the following have a contrast ratio of at least 3:1 against adjacent color(s):
10 |
11 |
12 |
13 |
User Interface Components
14 |
15 |
Visual information required to identify user interface components and states, except for inactive components or where the appearance of the component is determined by the user agent and not modified by the author;
16 |
17 |
Graphical Objects
18 |
19 |
Parts of graphics required to understand the content, except when a particular presentation of graphics is essential to the information being conveyed.
In content implemented using markup languages that support the following textstyle properties, no loss of content or functionality occurs by setting all of the following and by changing no other style property:
10 |
11 |
12 |
Line height (line spacing) to at least 1.5 times the font size;
13 |
Spacing following paragraphs to at least 2 times the font size;
14 |
Letter spacing (tracking) to at least 0.12 times the font size;
15 |
Word spacing to at least 0.16 times the font size.
16 |
17 |
18 |
Exception: Human languages and scripts that do not make use of one or more of these text style properties in written text can conform using only the properties that exist for that combination of language and script.
Either an alternative for time-based media or an audio track is provided that presents
27 | equivalent information for prerecorded video-only content.
28 |
phrase whose meaning cannot be deduced from the meaning of the individual words and
5 | the specific words cannot be changed without losing the meaning
6 |
7 |
8 |
idioms cannot be translated directly, word for word, without losing their (cultural
9 | or language-dependent) meaning.
10 |
11 |
12 |
In English, "spilling the beans" means "revealing a secret." However, "knocking over
13 | the beans" or "spilling the vegetables" does not mean the same thing.
14 |
15 |
16 |
In Japanese, the phrase "さじを投げる" literally translates into "he throws a spoon," but it means that there is nothing
17 | he can do and finally he gives up.
18 |
19 |
20 |
In Dutch, "Hij ging met de kippen op stok" literally translates into "He went to roost with the chickens," but it means that
21 | he went to bed early.
22 |
a part of the content that is perceived by users as a single control for a distinct
5 | function
6 |
7 |
8 |
Multiple user interface components may be implemented as a single programmatic element.
9 | Components here is not tied to programming techniques, but rather to what the user
10 | perceives as separate controls.
11 |
12 |
13 |
User interface components include form elements and links as well as components generated
14 | by scripts.
15 |
16 |
17 |
What is meant by "component" or "user interface component" here is also sometimes
18 | called "user interface element".
19 |
20 |
21 |
An applet has a "control" that can be used to move through content by line or page
22 | or random access. Since each of these would need to have a name and be settable independently,
23 | they would each be a "user interface component."
24 |
interface used by software to obtain keystroke input
5 |
6 |
A keyboard interface allows users to provide keystroke input to programs even if the
7 | native technology does not contain a keyboard.
8 |
9 |
10 |
A touchscreen PDA has a keyboard interface built into its operating system as well
11 | as a connector for external keyboards. Applications on the PDA can use the interface
12 | to obtain keyboard input either from an external keyboard or from other applications
13 | that provide simulated keyboard output, such as handwriting interpreters or speech-to-text
14 | applications with "keyboard emulation" functionality.
15 |
16 |
17 |
Operation of the application (or parts of the application) through a keyboard-operated
18 | mouse emulator, such as MouseKeys, does not qualify as operation through a keyboard
19 | interface because operation of the program is through its pointing device interface,
20 | not through its keyboard interface.
21 |
22 |
23 |
24 |
--------------------------------------------------------------------------------
/CONTRIBUTING.md:
--------------------------------------------------------------------------------
1 | Contributions to this repository are intended to become part of Recommendation-track documents governed by the
2 | [W3C Patent Policy](https://www.w3.org/Consortium/Patent-Policy-20040205/) and
3 | [Document License](https://www.w3.org/Consortium/Legal/copyright-documents). To make substantive contributions to specifications, you must either participate
4 | in the relevant W3C Working Group or make a non-member patent licensing commitment.
5 |
6 | If you are not the sole contributor to a contribution (pull request), please identify all
7 | contributors in the pull request comment.
8 |
9 | To add a contributor (other than yourself, that's automatic), mark them one per line as follows:
10 |
11 | ```
12 | +@github_username
13 | ```
14 |
15 | If you added a contributor by mistake, you can remove them in a comment with:
16 |
17 | ```
18 | -@github_username
19 | ```
20 |
21 | If you are making a pull request on behalf of someone else but you had no part in designing the
22 | feature, you can remove yourself with the above syntax.
23 |
24 | Public comments can be made by opening a new Issue https://github.com/w3c/wcag/issues/new. The public can also comment on any issue threads on Github https://github.com/w3c/wcag/issues.
25 |
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/guidelines/sc/20/contrast-minimum.html:
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1 |
2 |
3 |
Large-scale text and images of large-scale text have a contrast ratio of at least 3:1;
17 |
18 |
19 |
20 |
21 |
Incidental
22 |
23 |
24 |
25 |
Text or images of text that are part of an inactive user interface component, that are pure decoration, that are not visible to anyone, or that are part of a picture that contains significant
26 | other visual content, have no contrast requirement.
27 |
28 |
29 |
30 |
31 |
Logotypes
32 |
33 |
34 |
35 |
Text that is part of a logo or brand name has no contrast requirement.
Large-scale text and images of large-scale text have a contrast ratio of at least 4.5:1;
17 |
18 |
19 |
20 |
21 |
Incidental
22 |
23 |
24 |
25 |
Text or images of text that are part of an inactive user interface component, that are pure decoration, that are not visible to anyone, or that are part of a picture that contains significant
26 | other visual content, have no contrast requirement.
27 |
28 |
29 |
30 |
31 |
Logotypes
32 |
33 |
34 |
35 |
Text that is part of a logo or brand name has no contrast requirement.
Content can be presented without loss of information or functionality, and without requiring scrolling in two dimensions for:
10 |
11 |
Vertical scrolling content at a width equivalent to 320 CSS pixels;
12 |
Horizontal scrolling content at a height equivalent to 256 CSS pixels.
13 |
14 |
Except for parts of the content which require two-dimensional layout for usage or meaning.
15 |
16 |
Note: 320 CSS pixels is equivalent to a starting viewport width of 1280 CSS pixels wide at 400% zoom. For web content which are designed to scroll horizontally (e.g. with vertical text), the 256 CSS pixels is equivalent to a starting viewport height of 1024px at 400% zoom.
17 |
18 |
Examples of content which require two-dimensional layout are images, maps, diagrams,
19 | video, games, presentations, data tables, and interfaces where it is necessary to keep toolbars in view while
20 | manipulating content.
major changes in the content of the Web page that, if made without user awareness, can disorient users who are not able to view
5 | the entire page simultaneously
6 |
A change of content is not always a change of context. Changes in content, such as
26 | an expanding outline, dynamic menu, or a tab control do not necessarily change the
27 | context, unless they also change one of the above (e.g., focus).
28 |
29 |
30 |
Opening a new window, moving focus to a different component, going to a new page (including
31 | anything that would look to a user as if they had moved to a new page) or significantly
32 | re-arranging the content of a page are examples of changes of context.
33 |
synchronized visual and/or text alternative for both speech and non-speech audio information needed to understand the media content
5 |
6 |
7 |
Captions are similar to dialogue-only subtitles except captions convey not only the
8 | content of spoken dialogue, but also equivalents for non-dialogue audio information
9 | needed to understand the program content, including sound effects, music, laughter,
10 | speaker identification and location.
11 |
12 |
13 |
Closed Captions are equivalents that can be turned on and off with some players.
14 |
15 |
Open Captions are any captions that cannot be turned off. For example, if the captions
16 | are visual equivalent images of text embedded in video.
17 |
18 |
19 |
Captions should not obscure or obstruct relevant information in the video.
20 |
21 |
In some countries, captions are called subtitles.
22 |
23 |
Audio descriptions can be, but do not need to be, captioned since they are descriptions of information
24 | that is already presented visually.
25 |
Everyone makes mistakes. However, people with some disabilities have more difficulty
17 | creating error-free input. In addition, it may be harder for them to detect that they
18 | have made an error. Typical error indication methods may not be obvious to them because
19 | of a limited field of view, limited color perception, or use of assistive technology.
20 | This guideline seeks to reduce the number of serious or irreversible errors that are
21 | made, increase the likelihood that all errors will be noticed by the user, and help
22 | users understand what they should do to correct an error.
23 |
24 |
25 |
26 |
27 |
28 |
Additional Techniques (Advisory) for Input Assistance
The down-event of the pointer is not used to execute any part of the function;
15 |
16 |
Abort or Undo
17 |
Completion of the function is on the up-event, and a mechanism is available to abort the function before completion or to undo the function after completion;
18 |
19 |
Up Reversal
20 |
The up-event reverses any outcome of the preceding down-event;
21 |
22 |
Essential
23 |
Completing the function on the down-event is essential.
24 |
25 |
26 |
Functions that emulate a keyboard or numeric keypad key press are considered essential.
27 |
28 |
This requirement applies to web content that interprets pointer actions (i.e. this does not apply to actions that are required to operate the user agent or assistive technology).
Some people with seizure disorders can have a seizure triggered by flashing visual
17 | content. Most people are unaware that they have this disorder until it strikes. In
18 | 1997, a cartoon on television in Japan sent over 700 children to the hospital, including
19 | about 500 who had seizures. Warnings do not work well because they are often missed, especially by children
20 | who may in fact not be able to read them.
21 |
22 |
23 |
24 |
The objective of this guideline is to ensure that content that is marked as conforming
25 | to WCAG 2.0 avoids the types of flash that are most likely to cause seizure when viewed
26 | even for a second or two.
27 |
For prerecorded
8 | audio-only content that (1) contains primarily speech in the foreground, (2) is not an audio
9 | CAPTCHA or audio logo, and (3) is not vocalization intended to be primarily musical expression
10 | such as singing or rapping, at least one of the following is true:
11 |
12 |
13 |
14 |
15 |
No Background
16 |
17 |
18 |
19 |
The audio does not contain background sounds.
20 |
21 |
22 |
23 |
Turn Off
24 |
25 |
26 |
27 |
The background sounds can be turned off.
28 |
29 |
30 |
31 |
20 dB
32 |
33 |
34 |
35 |
The background sounds are at least 20 decibels lower than the foreground speech content,
36 | with the exception of occasional sounds that last for only one or two seconds.
37 |
38 |
39 |
Per the definition of "decibel," background sound that meets this requirement will
40 | be approximately four times quieter than the foreground speech content.
41 |
The purpose of this guideline is to support compatibility with current and future
17 | user agents,
18 | especially assistive technologies (AT). This is done both by 1) ensuring that authors do not
19 | do things that would break AT (e.g., poorly formed markup) or circumvent AT (e.g.,
20 | by using unconventional markup or code) and 2) exposing information in the content
21 | in standard ways that assistive technologies can recognize and interact with. Since
22 | technologies change quickly, and AT developers have much trouble keeping up with rapidly
23 | changing technologies, it is important that content follow conventions and be compatible
24 | with APIs so that AT can more easily work with new technologies as they evolve.
25 |
Many users who have disabilities need more time to complete tasks than the majority
17 | of users: they may take longer to physically respond, they may take longer to read
18 | things, they may have low vision and take longer to find things or to read them, or
19 | they may be accessing content through an assistive technology that requires more time.
20 | This guideline focuses on ensuring that users are able to complete the tasks required
21 | by the content with their own individual response times. The primary approaches deal
22 | with eliminating time constraints or providing users enough additional time to allow
23 | them to complete their tasks. Exceptions are provided for those cases where this is
24 | not possible.
25 |
While some guidelines are focused on making information available in a form that can
17 | be presented in alternate formats, this guideline is concerned with making the default
18 | presentation as easy to perceive as possible to people with disabilities. The primary
19 | focus is on making it easier for users to separate foreground information from the
20 | background. For visual presentations this involves making sure that information presented
21 | on top of a background contrasts sufficiently with the background. For audio presentations
22 | this involves making sure that foreground sounds are sufficiently louder than the
23 | background sounds. Individuals with visual and hearing disabilities have much greater
24 | difficulty separating foreground and background information.
25 |
26 |
27 |
28 |
29 |
30 |
Additional Techniques (Advisory) for Distinguishable
Where receiving and then removing pointer hover or keyboard focus triggers additional content to become visible and then hidden, the following are true:
10 |
11 |
12 |
13 |
Dismissable
14 |
A mechanism is available to dismiss the additional content without moving pointer hover or keyboard focus, unless the additional content communicates an input error or does not obscure or replace other content;
15 |
16 |
Hoverable
17 |
If pointer hover can trigger the additional content, then the pointer can be moved over the additional content without the additional content disappearing;
18 |
19 |
Persistent
20 |
The additional content remains visible until the hover or focus trigger is removed, the user dismisses it, or its information is no longer valid.
21 |
22 |
23 |
24 |
Exception: The visual presentation of the additional content is controlled by the user agent and is not modified by the author.
25 |
26 |
Examples of additional content controlled by the user agent include browser tooltips created through use of the HTML title attribute.
27 |
Custom tooltips, sub-menus, and other nonmodal popups that display on hover and focus are examples of additional content covered by this criterion.
shortened form of a word, phrase, or name where the abbreviation has not become part
5 | of the language
6 |
7 |
8 |
This includes initialisms and acronyms where:
9 |
10 |
11 |
12 |
13 |
14 |
initialisms are shortened forms of a name or phrase made from the initial letters of words or
15 | syllables contained in that name or phrase
16 |
17 |
18 |
Not defined in all languages.
19 |
20 |
SNCF is a French initialism that contains the initial letters of the Société Nationale des Chemins de Fer, the French national railroad.
21 |
22 |
23 |
ESP is an initialism for extrasensory perception.
24 |
25 |
26 |
27 |
28 |
29 |
acronyms are abbreviated forms made from the initial letters or parts of other words (in a
30 | name or phrase) which may be pronounced as a word
31 |
32 |
33 |
NOAA is an acronym made from the initial letters of the National Oceanic and Atmospheric
34 | Administration in the United States.
35 |
36 |
37 |
38 |
39 |
40 |
41 |
Some companies have adopted what used to be an initialism as their company name. In
42 | these cases, the new name of the company is the letters (for example, Ecma) and the
43 | word is no longer considered an abbreviation.
44 |
45 |
46 |
47 |
--------------------------------------------------------------------------------
/biblio.js:
--------------------------------------------------------------------------------
1 | var biblio = {
2 |
3 | "CAPTCHA": {
4 | "href": "http://www.captcha.net/",
5 | "publisher": "Carnegie Mellon University",
6 | "title": "The CAPTCHA Project"
7 | },
8 |
9 | "GPII": {
10 | "href": "https://gpii.net/",
11 | "title": "Global Public Inclusive Infrastructure"
12 | },
13 |
14 | "HARDING-BINNIE": {
15 | "authors": [
16 | "Harding G. F. A.",
17 | "Binnie, C.D."
18 | ],
19 | "date": "2002",
20 | "title": "Independent Analysis of the ITC Photosensitive Epilepsy Calibration Test Tape"
21 | },
22 |
23 | "IEC-4WD": {
24 | "date": "May 5, 1998",
25 | "title": "IEC/4WD 61966-2-1: Colour Measurement and Management in Multimedia Systems and Equipment - Part 2.1: Default Colour Space - sRGB",
26 | },
27 |
28 | "ISO_9241-112": {
29 | "uri": "https://www.iso.org/standard/64840.html",
30 | "title": "Ergonomics of human-system interaction -- Part 112: Principles for the presentation of information",
31 | "publisher": "International Standards Organization"
32 | },
33 |
34 | "sRGB": {
35 | "authors": [
36 | "M. Stokes",
37 | "M. Anderson",
38 | "S. Chandrasekar",
39 | "R. Motta"
40 | ],
41 | "date": "November 5, 1996",
42 | "href": "https://www.w3.org/Graphics/Color/sRGB.html",
43 | "title": "A Standard Default Color Space for the Internet - sRGB, Version 1.10"
44 | },
45 |
46 | "UNESCO": {
47 | "date": "1997",
48 | "href": "http://www.unesco.org/education/information/nfsunesco/doc/isced_1997.htm",
49 | "title": "International Standard Classification of Education"
50 | }
51 |
52 | };
53 |
--------------------------------------------------------------------------------
/understanding/20/text-alternatives.html:
--------------------------------------------------------------------------------
1 |
2 |
3 |
4 |
5 | Understanding Text Alternatives
6 |
7 |
8 |
9 |
Understanding Text Alternatives
10 |
11 |
12 |
13 |
Intent of Text Alternatives
14 |
15 |
16 |
The purpose of this guideline is to ensure that all non-text content is also available
17 | in
18 | text. "Text" refers to electronic text, not an image of text. Electronic text has the
19 | unique advantage that it is presentation neutral. That is, it
20 | can be rendered visually, auditorily, tactilely, or by any combination. As a result,
21 | information rendered in electronic text can be presented in whatever form best meets
22 | the needs of the user. It can also be easily enlarged, spoken aloud so that it is
23 | easier for people with reading disabilities to understand, or rendered in whatever
24 | tactile form best meets the needs of a user.
25 |
26 |
27 |
28 |
29 |
While changing the content into symbols includes changing it into graphic symbols
30 | for people with developmental disorders and speech comprehension difficulties, it
31 | is not limited to this use of symbols.
32 |
33 |
34 |
35 |
36 |
37 |
38 |
39 |
Additional Techniques (Advisory) for Text Alternatives
Some people with seizure disorders can have a seizure triggered by flashing visual
17 | content. Most people are unaware that they have this disorder until it strikes. In
18 | 1997, a cartoon on television in Japan sent over 700 children to the hospital, including
19 | about 500 who had seizures. Warnings do not work well because they are often missed, especially by children
20 | who may in fact not be able to read them.
21 |
22 |
23 |
24 |
The objective of this guideline is to ensure that content that is marked as conforming
25 | to WCAG 2.0 avoids the types of flash that are most likely to cause seizure when viewed
26 | even for a second or two.
27 |
28 |
29 |
30 |
31 |
32 |
Additional Techniques (Advisory) for Seizures
33 |
34 |
35 |
36 |
37 |
38 | Ensuring that content does not violate spatial pattern thresholds (future link)
39 |
40 |
a non-embedded resource obtained from a single URI using HTTP plus any other resources
5 | that are used in the rendering or intended to be rendered together with it by a user agent
6 |
7 |
Although any "other resources" would be rendered together with the primary resource,
8 | they would not necessarily be rendered simultaneously with each other.
9 |
10 |
11 |
For the purposes of conformance with these guidelines, a resource must be "non-embedded"
12 | within the scope of conformance to be considered a Web page.
13 |
14 |
15 |
A Web resource including all embedded images and media.
16 |
17 |
A Web mail program built using Asynchronous JavaScript and XML (AJAX). The program
18 | lives entirely at http://example.com/mail, but includes an inbox, a contacts area
19 | and a calendar. Links or buttons are provided that cause the inbox, contacts, or calendar
20 | to display, but do not change the URI of the page as a whole.
21 |
22 |
23 |
A customizable portal site, where users can choose content to display from a set of
24 | different content modules.
25 |
26 |
27 |
When you enter "http://shopping.example.com/" in your browser, you enter a movie-like
28 | interactive shopping environment where you visually move around in a store dragging
29 | products off of the shelves around you and into a visual shopping cart in front of
30 | you. Clicking on a product causes it to be demonstrated with a specification sheet
31 | floating alongside. This might be a single-page Web site or just one page within a
32 | Web site.
33 |
The purpose of this guideline is to ensure that all information is available in a
17 | form that can be perceived by all users, for example, spoken aloud, or presented in
18 | a simpler visual layout. If all of the information is available in a form that can
19 | be determined by software, then it can be presented to users in different ways (visually,
20 | audibly, tactilely etc.). If information is embedded in a particular presentation
21 | in such a way that the structure and information cannot be programmatically determined
22 | by the assistive technology, then it cannot be rendered in other formats as needed
23 | by the user.
24 |
25 |
26 |
The Success Criteria under this guideline all seek to ensure that different types
27 | of information that are often encoded in presentation are also available so that they
28 | can be presented in other modalities.
29 |
30 |
31 |
32 |
33 |
34 | the way the parts of a Web page are organized in relation to each other; and the way
35 | a collection of Web pages is organized
36 |
37 |
38 |
39 |
40 | rendering of the content in a form that can be perceived by users
41 |
42 |
43 |
44 |
45 |
46 |
47 |
48 |
49 |
50 |
51 |
52 |
53 |
--------------------------------------------------------------------------------
/techniques/general/G80.html:
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1 | Providing a submit button to initiate a change of context
Providing a submit button to initiate a change of context
ID: G80
Technology: general
Type: Technique
When to Use
2 |
Content that includes forms.
3 |
Description
4 |
The objective of this technique is to provide a mechanism that allows users
5 | to explicitly request changes of context. Since the intended use of a submit
6 | button is to generate an HTTP request that submits data entered in a form,
7 | this is an appropriate control to use for causing a change of context and is
8 | a practice that does not create confusion for users.
9 |
Examples
10 |
11 |
Description
12 |
Example 1: A submit button is used for each form that causes a
13 | change in context.
This technique relates to all markup languages with specifications.
3 |
Description
4 |
When markup languages are used in a way that fully conforms to their specifications, all of the requirements in 4.1.1 are met. Therefore, while fully conforming to specifications is not required to conform to WCAG 2.0, it is a best practice and is sufficient to meet Success Criterion 4.1.1.
5 |
Examples
6 |
7 |
A page is created with care to make sure that all technologies are used according to specification. It is run through a validator and all identified errors are corrected. Specification requirements that can not be identified by validation are also checked and any failures are corrected.
8 |
9 |
Tests
10 |
Procedure
11 |
12 |
Check that all technologies are used according to specification.
13 |
14 |
15 |
While validators can be great tools for catching errors, they usually cannot catch all cases where content fails to fully conform to a specification.
If all
17 | functionality can be achieved using the keyboard, it can be accomplished by keyboard users, by
18 | speech input (which creates keyboard input), by mouse (using on-screen keyboards),
19 | and by a wide variety of assistive technologies that create simulated keystrokes as
20 | their output. No other input form has this flexibility or is universally supported
21 | and operable by people with different disabilities, as long as the keyboard input
22 | is not time-dependent.
23 |
24 |
25 |
Note that providing universal keyboard input does not mean that other types of input
26 | should not be supported. Optimized speech input, optimized mouse/pointer input, etc.,
27 | are also good. The key is to provide keyboard input and control as well.
28 |
29 |
30 |
Some devices do not have native keyboards—for example, a PDA or cell phone. If these
31 | devices have a Web browsing capability, however, they will have some means of generating
32 | text or "keystrokes". This guideline uses the term "
33 | keyboard interface" to acknowledge that Web content should be controlled from keystrokes that may come
34 | from a keyboard, keyboard emulator, or other hardware or software that generates keyboard
35 | or text input.
36 |
37 |
38 |
39 |
40 |
41 |
Additional Techniques (Advisory) for Keyboard Accessible
42 |
43 |
44 |
45 |
46 |
47 |
48 |
49 |
50 |
51 |
--------------------------------------------------------------------------------
/techniques/general/G91.html:
--------------------------------------------------------------------------------
1 | Providing link text that describes the purpose of a link
Providing link text that describes the purpose of a link
ID: G91
Technology: general
Type: Technique
When to Use
2 |
All technologies that contain links.
3 |
Description
4 |
The objective of this technique is to describe the purpose of a link in the text of the link. The description lets a user distinguish this link from links in the Web page that lead to other destinations and helps the user determine whether to follow the link. The URI of the destination is generally not sufficiently descriptive.
5 |
Examples
6 |
7 |
Example 1: Describing the purpose of a link in HTML in the text content of the
8 |
9 | a
10 |
11 | element
12 |
13 | <a href="routes.html">
14 | Current routes at Boulders Climbing Gym
15 | </a>
16 |
17 |
18 |
Tests
19 |
Procedure
20 |
For each link in the content that uses this technique:
21 |
22 |
Check that text of the link describes the purpose of the link
23 |
24 |
25 |
Expected Results
26 |
27 |
The above check is true.
28 |
29 |
30 |
Related Techniques
31 |
32 |
Resources
--------------------------------------------------------------------------------
/techniques/css/C24.html:
--------------------------------------------------------------------------------
1 | Using percentage values in CSS for container sizes
Using percentage values in CSS for container sizes
ID: C24
Technology: css
Type: Technique
When to Use
2 |
Pages that use CSS.
3 |
Description
4 |
The objective of this technique is to enable users to increase the size of text without having to scroll horizontally to read that text. To use this technique, an author specifies the width of text containers using percent values.
5 |
Examples
6 |
7 |
Description
8 |
A newspaper has content in the middle of the window. The width of the container for the content is specified in page percentages, so that when a person with low vision increases the font size the text reflows inside the browser window at the new size and there is no need to scroll horizontally.
9 |
10 |
11 |
Tests
12 |
Procedure
13 |
14 |
Check that all container widths are specified as percentage values.
15 |
Increase the text size to 200%.
16 |
Check to make sure that horizontal scrolling is not required to read any line of text.
The intent of this Guideline is to help users with disabilities by presenting content
17 | in a predictable order from Web page to Web page and by making the behavior of functional
18 | and interactive components predictable. It is difficult for some users to form an
19 | overview of the Web page: screen readers present content as a one-dimensional stream
20 | of synthetic speech that makes it difficult to understand spatial relationships. Users
21 | with cognitive limitations may become confused if components appear in different places
22 | on different pages.
23 |
24 |
25 |
For example, people who use screen magnifiers see only part of the screen at any point
26 | in time; a consistent layout makes it easier for them to find navigation bars and
27 | other components. Placing repeated components in the same relative order within a
28 | set of Web pages allows users with reading disabilities to focus on an area of the
29 | screen rather than spending additional time decoding the text of each link. Users
30 | with limited use of their hands can more easily determine how to complete their tasks
31 | using the fewest keystrokes.
32 |
33 |
34 |
35 |
36 |
37 |
Additional Techniques (Advisory) for Predictable
38 |
39 |
40 |
41 |
42 |
43 | Positioning labels to maximize predictability of relationships
44 |
45 |
46 |
The intent of this Success Criterion is to ensure that
17 | all content is operable from the keyboard. This is the same as Success Criterion 2.1.1,
18 | except that no exceptions are allowed. This does not mean that content where the underlying
19 | function requires input that depends on the path of the user's movement and not just
20 | the endpoints (excluded from the requirements of 2.1.1) must be made keyboard accessible.
21 | Rather, it means that content that uses path-dependent input cannot conform to this
22 | Success Criterion and therefore cannot meet Guideline 2.1 at Level AAA.
23 |
24 |
25 |
26 |
27 |
28 |
Examples of Keyboard (No Exception)
29 |
30 |
31 |
32 |
33 |
34 |
Resources for Keyboard (No Exception)
35 |
36 |
37 |
38 |
39 |
40 |
Techniques for Keyboard (No Exception)
41 |
42 |
43 |
44 |
Sufficient Techniques for Keyboard (No Exception)
45 |
46 |
47 |
No additional techniques exist for this Success Criterion. Follow
48 | techniques for Success Criterion 2.1.1. If that is not possible because there is a requirement for path-dependent input,
49 | then it is not possible to meet this Level AAA Success Criterion.
50 |
51 |
52 |
53 |
54 |
55 |
56 |
57 |
58 |
--------------------------------------------------------------------------------
/techniques/general/G198.html:
--------------------------------------------------------------------------------
1 | Providing a way for the user to turn the time limit off
Providing a way for the user to turn the time limit off
ID: G198
Technology: general
Type: Technique
When to Use
2 |
This technique relates to all technologies.
3 |
Description
4 |
The objective of this technique is to provide a mechanism for people who cannot complete tasks within a specified time limit to turn off the time limit.
5 |
It is essential that the mechanism for turning off the time limit can be completed without a time limit itself and before the time limit for the page expires. To do this - the mechanism should be available at or near the top of the page so that it can be found and activated quickly by people with a wide range of disabilities.
6 |
Examples
7 |
8 |
A page has a listing of news headlines that automatically update every minute. At the top of the page is a link that turns off the updating.
9 |
10 |
Tests
11 |
Procedure
12 |
13 |
Check that there is a mechanism to turn off any time limits near the top of the page.
14 |
Verify that the time limit for the page is long enough that a user can easily navigate to the mechanism even if they are 10 times slower than most users.
15 |
16 |
17 |
Expected Results
18 |
19 |
Checks #1 and #2 are true.
20 |
21 |
22 |
Related Techniques
23 |
24 |
25 |
26 |
27 |
28 |
29 |
--------------------------------------------------------------------------------
/techniques/html/H35.html:
--------------------------------------------------------------------------------
1 | Providing text alternatives on applet elements
Providing text alternatives on applet elements
ID: H35
Technology: html
Type: Technique
When to Use
2 |
HTML and XHTML Documents that load Java applets where applet is not deprecated.
3 |
4 |
Description
5 |
Provide a text alternative for an applet by using the alt attribute to label an applet
6 | and providing the text alternative in the body of the applet element. In this technique, both mechanisms
7 | are required due to the varying support of the alt attribute and applet body text by
8 | user agents.
9 |
Examples
10 |
11 |
Example 1: An applet to play the tic-tac-toe game.
Check that the applet element contains an alt attribute with a text alternative
21 | for the applet
22 |
Check that the applet element contains a text alternative for the applet in the
23 | body of the applet element
24 |
25 |
26 |
Expected Results
27 |
28 |
Checks #2 and #3 are true.
29 |
30 |
31 |
Related Techniques
32 |
33 |
--------------------------------------------------------------------------------
/techniques/general/G75.html:
--------------------------------------------------------------------------------
1 | Providing a mechanism to postpone any updating of content
Providing a mechanism to postpone any updating of content
ID: G75
Technology: general
Type: Technique
When to Use
2 |
Content that automatically updates itself.
3 |
Description
4 |
The objective of this technique is to ensure that users can postpone automatic updates of content, or other non-emergency interruptions. This can be accomplished either through a preference or by alerting users of an imminent update and allowing them to suppress it. If a preference is provided, automatic content update can be disabled by default and users can specify the frequency of automatic content updates if they choose to enable the setting.
5 |
Examples
6 |
7 |
A Web page provides stock quotes and automatically updates from time to time. The page provides a short form with a field "Refresh data frequency (minutes):" so users can adjust the frequency of the updating.
8 |
9 |
Tests
10 |
Procedure
11 |
12 |
Find pages with content that automatically updates.
13 |
For each automatic update, look for a mechanism to adjust the timing of the updates.
14 |
Check that automatic updating is disabled by default or that the user is warned before an automatic update occurs and allowed to suppress it.
Contrast ratios can range from 1 to 21 (commonly written 1:1 to 21:1).
17 |
18 |
Because authors do not have control over user settings as to how text is rendered
19 | (for example font smoothing or anti-aliasing), the contrast ratio for text can be
20 | evaluated with anti-aliasing turned off.
21 |
22 |
23 |
For the purpose of Success Criteria 1.4.3 and 1.4.6, contrast is measured with respect
24 | to the specified background over which the text is rendered in normal usage. If no
25 | background color is specified, then white is assumed.
26 |
27 |
28 |
Background color is the specified color of content over which the text is to be rendered
29 | in normal usage. It is a failure if no background color is specified when the text
30 | color is specified, because the user's default background color is unknown and cannot
31 | be evaluated for sufficient contrast. For the same reason, it is a failure if no text
32 | color is specified when a background color is specified.
33 |
34 |
35 |
When there is a border around the letter, the border can add contrast and would be
36 | used in calculating the contrast between the letter and its background. A narrow border
37 | around the letter would be used as the letter. A wide border around the letter that
38 | fills in the inner details of the letters acts as a halo and would be considered background.
39 |
40 |
41 |
WCAG conformance should be evaluated for color pairs specified in the content that
42 | an author would expect to appear adjacent in typical presentation. Authors need not
43 | consider unusual presentations, such as color changes made by the user agent, except
44 | where caused by authors' code.
45 |
The intent of this guideline is to allow text content to be read by users and by assistive
17 | technology, and to ensure that information necessary for understanding it is available.
18 |
19 |
20 |
People with disabilities experience text in many different ways. For some the experience
21 | is visual; for some it is auditory; for some it is tactile; for still others it is
22 | both visual and auditory. Some users experience great difficulty in recognizing written
23 | words yet understand extremely complex and sophisticated documents when the text is
24 | read aloud, or when key processes and ideas are illustrated visually or interpreted
25 | as sign language. For some users, it is difficult to infer the meaning of a word or
26 | phrase from context, especially when the word or phrase is used in an unusual way
27 | or has been given a specialized meaning; for these users the ability to read and understand
28 | may depend on the availability of specific definitions or the expanded forms of acronyms
29 | or abbreviations. User agents, including speech-enabled as well as graphical applications,
30 | may be unable to present text correctly unless the language and direction of the text
31 | are identified; while these may be minor problems for most users, they can be enormous
32 | barriers for users with disabilities. In cases where meaning cannot be determined
33 | without pronunciation information (for example, certain Japanese Kanji characters),
34 | pronunciation information must be available as well
35 |
Any synchronized media technology, even ones that do not support closed captions.
3 |
Description
4 |
The objective of this technique is to provide a way for people who are deaf or otherwise have trouble hearing the dialogue in audio visual material to be able to view the material. With this technique all of the dialogue and important sounds are embedded as text in the video track. As a result they are always visible and no special support for captioning is required by the user agent.
5 |
NOTE: Captions should not be confused with subtitles. Subtitles provide text of only the dialogue and do not include important sounds.
6 |
Examples
7 |
8 |
In order to ensure that everyone can view their online movies, even if users do not know how to turn on captions in their media player, a library association puts the captions directly into the video.
9 |
A news organization provides open captions on all of its material.
10 |
11 |
Tests
12 |
Procedure
13 |
14 |
Watch the synchronized media with closed captioning turned off.
15 |
Check that captions (of all dialogue and important sounds) are visible.
16 |
17 |
18 |
Expected Results
19 |
20 |
#2 is true
21 |
22 |
23 |
Related Techniques
24 |
25 |
Resources
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/techniques/general/G143.html:
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1 | Providing a text alternative that describes the purpose of the CAPTCHA
Providing a text alternative that describes the purpose of the CAPTCHA
ID: G143
Technology: general
Type: Technique
When to Use
2 |
Applies to all technologies.
3 |
Description
4 |
The purpose of this technique is to provide information via the text alternative that identifies the non-text content as a
5 | CAPTCHA. Such tests often involve asking the user to type in text that is presented in an obscured image or audio file. From the text alternative, the user can tell that the CAPTCHA requires completing a task and what type of task it is.
6 |
When an alternate version of a CAPTCHA is available, the text alternative should include instructions about how to find the alternate version.
7 |
Examples
8 |
9 |
A CAPTCHA test asks the user to type in text that is displayed in an obscured image. The text alternative is "Type the word in the image".
10 |
A CAPTCHA test asks the user to type in text that is played in an audio file. The text alternative is "Type the letters spoken in the audio".
11 |
12 |
Tests
13 |
Procedure
14 |
15 |
Remove, hide, or mask the CAPTCHA.
16 |
Replace it with the text alternative.
17 |
Check that the text alternative describes the purpose of the CAPTCHA.
For each time limit that is set by the content, at least one of the following is true:
8 |
9 |
10 |
11 |
Turn off
12 |
13 |
14 |
15 |
The user is allowed to turn off the time limit before encountering it; or
16 |
17 |
18 |
19 |
Adjust
20 |
21 |
22 |
23 |
The user is allowed to adjust the time limit before encountering it over a wide range
24 | that is at least ten times the length of the default setting; or
25 |
26 |
27 |
28 |
29 |
Extend
30 |
31 |
32 |
33 |
The user is warned before time expires and given at least 20 seconds to extend the
34 | time limit with a simple action (for example, "press the space bar"), and the user
35 | is allowed to extend the time limit at least ten times; or
36 |
37 |
38 |
39 |
40 |
Real-time Exception
41 |
42 |
43 |
44 |
The time limit is a required part of a real-time event (for example, an auction),
45 | and no alternative to the time limit is possible; or
46 |
47 |
48 |
49 |
50 |
Essential Exception
51 |
52 |
53 |
54 |
The time limit is essential and extending it would invalidate the activity; or
55 |
56 |
57 |
58 |
59 |
20 Hour Exception
60 |
61 |
62 |
63 |
The time limit is longer than 20 hours.
64 |
65 |
66 |
67 |
68 |
69 |
This success criterion helps ensure that users can complete tasks without unexpected
70 | changes in content or context that are a result of a time limit. This success criterion
71 | should be considered in conjunction with Success Criterion 3.2.1, which puts limits on changes of content or context as a result of user action.
72 |
73 |
74 |
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/techniques/general/G142.html:
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1 | Using a technology that has commonly-available user agents that support zoom
Using a technology that has commonly-available user agents that support zoom
ID: G142
Technology: general
Type: Technique
When to Use
2 |
All technologies with user-agent provided zoom capability.
3 |
Description
4 |
The objective of this technique is to ensure content can be scaled uniformly by using a Web technology supported by user agents that change text size via a Zoom tool.
5 |
Content authored in technologies that are supported by user agents that can scale content uniformly (that is, zoom into content) satisfy this Success Criterion. Because this technique relies completely on user agent functionality, it is critical to test with a wide variety of user agents.
6 |
This technique requires that the zoom function preserve all spatial relationships on the page and that all functionality continues to be available.
7 |
Examples
8 |
9 |
Internet Explorer 7 and Opera 9 provide a zoom function that scales HTML/CSS page content uniformly.
10 |
To allow users to resize text, Adobe Reader provides a magnification tool that scales PDF pages uniformly.
11 |
12 |
Tests
13 |
Procedure
14 |
15 |
Display content in a user agent
16 |
Zoom content to 200%
17 |
Check whether all content and functionality is available
18 |
19 |
20 |
Expected Results
21 |
22 |
Check #3 is true.
23 |
24 |
25 |
Related Techniques
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/techniques/general/G11.html:
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1 | Creating content that blinks for less than 5 seconds
Creating content that blinks for less than 5 seconds
ID: G11
Technology: general
Type: Technique
When to Use
2 |
Technologies that support blinking content.
3 |
Description
4 |
The objective of this technique is to minimize the distraction caused by blinking content and enable users to re-focus on the other content on the page.
5 |
Blinking content can be created using a variety of technologies, many of which include options to loop blinking content continuously or to otherwise specify the amount of time the blinking content is displayed. Limiting the blinking of content to five seconds minimizes the distraction that blinking can cause. This will benefit people with certain types of learning disabilities and people with low vision.
6 |
Examples
7 |
8 |
An animated image is used to highlight items on sale. Within a list of items for purchase, an image of a red tag followed by the phrase "On sale" is used to indicate items being offered at a reduced price. The image of the red tag blinks on loading of the page and stops within five seconds.
9 |
10 |
Tests
11 |
Procedure
12 |
13 |
Find all items that blink.
14 |
For each item that blinks, determine if the interval between the start and end of the blinking is less than five seconds.
with at least 18 point or 14 point bold or font size that would yield equivalent size
6 | for Chinese, Japanese and Korean (CJK) fonts
7 |
8 |
9 |
Fonts with extraordinarily thin strokes or unusual features and characteristics that
10 | reduce the familiarity of their letter forms are harder to read, especially at lower
11 | contrast levels.
12 |
13 |
14 |
Font size is the size when the content is delivered. It does not include resizing
15 | that may be done by a user.
16 |
17 |
18 |
The actual size of the character that a user sees is dependent both on the author-defined
19 | size and the user's display or user-agent settings. For many mainstream body text
20 | fonts, 14 and 18 point is roughly equivalent to 1.2 and 1.5 em or to 120% or 150%
21 | of the default size for body text (assuming that the body font is 100%), but authors
22 | would need to check this for the particular fonts in use. When fonts are defined in
23 | relative units, the actual point size is calculated by the user agent for display.
24 | The point size should be obtained from the user agent, or calculated based on font
25 | metrics as the user agent does, when evaluating this success criterion. Users who
26 | have low vision would be responsible for choosing appropriate settings.
27 |
28 |
29 |
When using text without specifying the font size, the smallest font size used on major
30 | browsers for unspecified text would be a reasonable size to assume for the font. If
31 | a level 1 heading is rendered in 14pt bold or higher on major browsers, then it would
32 | be reasonable to assume it is large text. Relative scaling can be calculated from
33 | the default sizes in a similar fashion.
34 |
35 |
36 |
The 18 and 14 point sizes for roman texts are taken from the minimum size for large
37 | print (14pt) and the larger standard font size (18pt). For other fonts such as CJK
38 | languages, the "equivalent" sizes would be the minimum large print size used for those
39 | languages and the next larger standard large print size.
40 |
41 |
42 |
43 |
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/techniques/html/H67.html:
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1 | Using null alt text and no title attribute on img elements for images that AT
2 | should ignore
Using null alt text and no title attribute on img elements for images that AT
3 | should ignore
ID: H67
Technology: html
Type: Technique
When to Use
4 |
HTML and XHTML documents that load images.
5 |
Description
6 |
The purpose of this technique is to show how images can be marked so that they can be
7 | ignored by Assistive Technology.
8 |
If no title attribute is used, and the alt text is set to null (i.e.
9 |
10 | alt="") it indicates to assistive technology that the image can be safely
11 | ignored.
12 |
13 |
Have a "null" alt attribute is not the same as having no alt attribute.
14 |
15 |
Examples
16 |
17 |
Description
18 |
The following image is used to insert a decorative image on a Web page.
Technology: ARIA | CSS | General | HTML | PDF | Script | Server | Text
13 |
Type: Technique | Failure
14 |
15 |
16 |
When to Use
17 |
Describe the situations in which to use the technique, such as types of pages, features in use that might use the technique, etc.
18 |
19 |
20 |
Description
21 |
Describe how the technique works. This begins with a description of the problem the technique solves, then describes how to apply the technique. The description should be detailed enough to provide all the information a reader needs to be able to apply the technique, without recourse to following example code.
22 |
The objective of this technique is to ...
23 |
24 |
25 |
Examples
26 |
Copy the following section for each example. Examples must have a title and a description, and usually have a code sample. Code samples should be elided if necessary to show the core of the technique without necessarily providing all the surrounding code that would also be involved. A working example link references a location where the technique can be shown working live.
the relative brightness of any point in a colorspace, normalized to 0 for darkest
5 | black and 1 for lightest white
6 |
7 |
8 |
9 |
For the sRGB colorspace, the relative luminance of a color is defined as L = 0.2126
10 | * R + 0.7152 * G + 0.0722 * B where R, G and B are defined as:
11 |
12 |
13 |
14 |
15 |
if RsRGB <= 0.03928 then R = RsRGB/12.92 else R = ((RsRGB+0.055)/1.055) ^ 2.4
16 |
17 |
18 |
if GsRGB <= 0.03928 then G = GsRGB/12.92 else G = ((GsRGB+0.055)/1.055) ^ 2.4
19 |
20 |
21 |
if BsRGB <= 0.03928 then B = BsRGB/12.92 else B = ((BsRGB+0.055)/1.055) ^ 2.4
22 |
23 |
24 |
25 |
26 |
and RsRGB, GsRGB, and BsRGB are defined as:
27 |
28 |
29 |
30 |
RsRGB = R8bit/255
31 |
32 |
GsRGB = G8bit/255
33 |
34 |
BsRGB = B8bit/255
35 |
36 |
37 |
38 |
The "^" character is the exponentiation operator. (Formula taken from [[sRGB]] and
39 | [[IEC-4WD]]).
40 |
41 |
42 |
43 |
44 |
Almost all systems used today to view Web content assume sRGB encoding. Unless it
45 | is known that another color space will be used to process and display the content,
46 | authors should evaluate using sRGB colorspace. If using other color spaces, see Understanding Success Criterion 1.4.3.
47 |
48 |
49 |
If dithering occurs after delivery, then the source color value is used. For colors
50 | that are dithered at the source, the average values of the colors that are dithered
51 | should be used (average R, average G, and average B).
52 |
53 |
54 |
Tools are available that automatically do the calculations when testing contrast and
55 | flash.
56 |
62 |
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/techniques/general/G144.html:
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1 | Ensuring that the Web Page contains another CAPTCHA serving the same purpose using a different modality
Ensuring that the Web Page contains another CAPTCHA serving the same purpose using a different modality
ID: G144
Technology: general
Type: Technique
When to Use
2 |
Applies to all technologies.
3 |
Description
4 |
The purpose of this technique is to reduce occasions in which a user with a disability cannot complete a CAPTCHA task. Because there are alternate CAPTCHA tasks that use different modalities, a user is more likely to be able to complete one of the tasks successfully.
5 |
Examples
6 |
7 |
A Web page that includes a CAPTCHA test that must be completed successfully before the user can advance to the next step in a process. The page includes both a visual task, such as typing words displayed in a image, and an audio task, such as typing letters spoken in an audio file. A user with hearing disabilities who cannot pass the audio CAPTCHA may be able to pass the visual CAPTCHA.
8 |
A blog comment form includes a visual CAPTCHA that must be completed before a user can submit comments. In addition to the visual CAPTCHA, it includes a CAPTCHA with a form field that asks, "What is two plus seven?" with a text entry field that allows users to enter the correct answer.
9 |
10 |
Tests
11 |
Procedure
12 |
For each CAPTCHA in a Web page
13 |
14 |
Check that the Web page contains another CAPTCHA for the same purpose but using a different modality.
15 |
16 |
17 |
Expected Results
18 |
19 |
Check #1 is true.
20 |
21 |
22 |
Related Techniques
23 |
24 |
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/techniques/general/G89.html:
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1 | Providing expected data format and example
Providing expected data format and example
ID: G89
Technology: general
Type: Technique
When to Use
2 |
Pages that collect information from users, and restrict the format the user can use.
3 |
Description
4 |
The objective of this technique is to help the user avoid input errors by informing them about restrictions on the format of data that they must enter. This can be done by describing characteristics of the format or providing a sample of the format the data should have.
5 |
6 |
For data formats with common variations, such as dates and times, it may be useful to provide a preference option so users can use the format that is most comfortable to them.
7 |
8 |
Examples
9 |
10 |
Description
11 |
The following HTML form control for a date indicates in the label that the date must be in day-month-year format, not month-day-year as many users in the United States may assume.
Identify form controls that will only accept user input data in a given format.
22 |
Determine if each of the form controls identified in 1 provides information about the expected format.
23 |
24 |
25 |
Expected Results
26 |
27 |
#2 is true.
28 |
29 |
30 |
Related Techniques
31 |
32 |
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/techniques/general/G60.html:
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1 | Playing a sound that turns off automatically within three seconds
Playing a sound that turns off automatically within three seconds
ID: G60
Technology: general
Type: Technique
When to Use
2 |
Applies to all technologies except those for voice interaction.
3 |
Description
4 |
The purpose of this technique is to allow authors to play a sound on their
5 | Web page but avoid the problem of users not being able to use their screen
6 | readers due to interference by the content sound. It also allows the author
7 | to avoid putting controls on the Web page to control the sound - and the problem
8 | faced by users with screen readers in finding the control (when unable
9 | to hear their screen reader).
10 |
The technique is simple. The sound plays for 3 or less seconds and stops
11 | automatically.
12 |
Examples
13 |
14 |
Example 1: A Web page opens with a trumpet fanfare and then goes silent
15 |
Example 2: A homepage opens with the chairman saying "Binfor, where quality is our business." then going silent.
16 |
Example 3: A Web page opens with instructions on how to get started: "To begin, press the enter key."
17 |
Example 4: A Web page opens with a warning and then goes silent.
18 |
19 |
Tests
20 |
Procedure
21 |
22 |
Load the Web page
23 |
Check that all sound that plays automatically stops in 3 seconds
24 | or less
Applies to all technologies where content includes functionality.
3 |
Description
4 |
The objective of this technique is to permit individuals who rely on a keyboard or keyboard interface to access the functionality of the content. To do this, make sure that all event handlers triggered by non-keyboard UI events are also associated with a keyboard-based event, or provide redundant keyboard-based mechanisms to accomplish the functionality provided by other device-specific functions.
5 |
Examples
6 |
7 |
8 | Example 1: A drag and drop feature
9 | A photo application includes a "drag" and "drop" feature to allow users to re-order photographs in an on-line album for presentation as a slide show. It also includes a feature that allows users to select a photo and 'cut' and 'paste' the items into the list at the appropriate point using only the keyboard.
10 |
11 | Example 2: A reorder feature
12 | A Web application that allows users to create surveys by dragging questions into position includes a list of the questions followed by a text field that allows users to re-order questions as needed by entering the desired question number.
13 |
14 |
Tests
15 |
Procedure
16 |
17 |
check that all functionality can be accessed using only the keyboard
18 |
19 |
20 |
Expected Results
21 |
22 |
#1 is true
23 |
24 |
25 |
Related Techniques
26 |
27 |
28 |
29 |
Resources
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/techniques/general/G150.html:
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1 | Providing text based alternatives for live audio-only content
Providing text based alternatives for live audio-only content
ID: G150
Technology: general
Type: Technique
When to Use
2 |
All technologies that present live audio-only information
3 |
Description
4 |
The objective of this technique is to allow users who cannot hear to be able to access real-time audio broadcasts. It is more difficult to create accurate real-time alternatives because there is little time to correct mistakes, to listen a second time or to consult someone to be sure the words are accurately reproduced. It is also harder to simplify or paraphrase information if it is flowing too quickly.
5 |
Real-time typing text entry techniques exist using stenographic and rapid typing technologies. Re-voicing speech-to-text (where a person listens to speech and then carefully re-voices it into a computer trained to their speech) is used today for telephone relay services and may be used in the future for captioning. Eventually speech-to-text with correction will be possible.
6 |
Examples
7 |
8 |
A radio station uses Web based captioning services to provide alternatives for live sporting events; the output from the service is incorporated in a viewport of the Web page which also includes a streaming audio control.
9 |
10 |
Tests
11 |
Procedure
12 |
13 |
Check that a procedure and policy is in place to ensure that text alternatives are delivered in real-time.
14 |
Check that procedure and policy are working by conducting a random sample to see if text alternatives appear.
15 |
16 |
17 |
Expected Results
18 |
19 |
Both #1 and #2 are true.
20 |
21 |
22 |
Related Techniques
23 |
24 |
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/techniques/general/G185.html:
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1 | Linking to all of the pages on the site from the home page
Linking to all of the pages on the site from the home page
ID: G185
Technology: general
Type: Technique
When to Use
2 |
All technologies that contain links.
3 |
Description
4 |
The objective of this technique is to make it possible for users to locate all the information in a small Web site by providing links to all Web pages from the home page. When the number of pages in the site is small enough, the home page can contain site map information directly. The other pages in the Web site contain links to the home page.
5 |
In this way, the home page serves as two mechanisms in one. It provides the usual navigation to pages. It also is a de facto site map to the site.
A small commercial Web site for a consultant contains a home page, a Contacts page for contacting the consultant, a page describing the consultant's background, and a page with examples of the consultant's work. Each page contains a navigation bar that links to all the other pages in the site.
11 |
12 |
Tests
13 |
Procedure
14 |
15 |
Check that the home page contains links to all other pages in the Web site.
16 |
Check that all other pages in the Web site contain links to the home page.
17 |
18 |
19 |
Expected Results
20 |
21 |
All of the above checks are true.
22 |
23 |
24 |
Related Techniques
25 |
26 |
27 |
28 |
29 |
30 |
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/techniques/general/G100.html:
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1 | Providing a short text alternative which is the accepted name or a descriptive name of the non-text content
Providing a short text alternative which is the accepted name or a descriptive name of the non-text content
ID: G100
Technology: general
Type: Technique
When to Use
2 |
All technologies
3 |
Description
4 |
The objective of this technique is to allow users to identify the non-text
5 | content even if the non-text content is intended to provide a specific
6 | sensory experience. For example, a deaf person may want to know what an
7 | audio instrumental file is - even if they cannot hear it. Similarly, a blind
8 | person may want to know what the subject of a visual image is - even if they
9 | cannot see it.
10 |
Examples
11 |
12 |
Description
13 |
14 |
A painting of the Mona Lisa has an alternate text of "Mona Lisa, by Leonardo da Vinci".
15 |
A sound file has an alternate text of "5 Grade children playing a Theramin".
16 |
A famous modern art piece is labeled "Red, Blue and Yellow, by Piet Mondrian".
17 |
18 |
19 |
20 |
Tests
21 |
Procedure
22 |
23 |
Check that short text alternative provides a descriptive name.
24 |
Check that short text alternative provides a name that has be previously been given to the non-text content by the author or another.
25 |
26 |
27 |
Expected Results
28 |
29 |
#1 or #2 is true
30 |
31 |
32 |
Related Techniques
33 |
34 |
Resources
35 |
36 |
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/techniques/general/G187.html:
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1 | Using a technology to include blinking content that can be turned off via the user agent
Using a technology to include blinking content that can be turned off via the user agent
ID: G187
Technology: general
Type: Technique
When to Use
2 |
All technologies.
3 |
Description
4 |
The objective of this technique is to ensure that blinking content can be turned off using user agent features. User agents allow users to stop animation of content in certain technologies. When the user activates this feature, all animation, including blinking, is stopped. This feature can be provided either through interactive controls that conform to WCAG or through documented keyboard shortcuts.
5 |
The most common way for users to stop animation is to press the "escape" key. As long as there are no processes that take precedence in the event queue for a press of that key, this is taken as a command to stop animation of moving or blinking content.
6 |
Technologies for which this is known generally to work include:
7 |
8 |
Graphics Interchange Format (GIF)
9 |
Animated Portable Network Graphics (APNG)
10 |
11 |
Examples
12 |
13 |
A page contains a blinking banner intended to draw the user's attention to it. The banner is an animated gif image which repeats indefinitely. The user presses the "escape" key, which causes the user agent to stop the animation of all animated gif images on the page.
14 |
15 |
Tests
16 |
Procedure
17 |
18 |
Load a page that includes blinking content.
19 |
Activate the browser's stop animation command (usually the Escape key).
20 |
Check to see if the blinking stops.
21 |
22 |
23 |
Expected Results
24 |
25 |
Check #3 is true.
26 |
27 |
28 |
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/techniques/general/G193.html:
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1 | Providing help by an assistant in the Web page
Providing help by an assistant in the Web page
ID: G193
Technology: general
Type: Technique
When to Use
2 |
All technologies.
3 |
Description
4 |
The purpose of this technique is to provide help using a multimedia avatar that provides assistance in using the Web page. An avatar can be particularly helpful to people with cognitive disabilities who may have trouble reading text. The use of visuals will help some people to focus on the material presented.
5 |
6 |
The multimedia avatar must also satisfy relevant Success Criterion in
7 | Guideline 1.2.
8 |
9 |
Examples
10 |
11 |
The home page of an online banking application has an embedded avatar named Vanna. She gives new online banking clients a tour of the features provided in the application. The assistant can be started and stopped and paused. The client can rewind and fast forward through the material. A text alternative of the information is available from a link next to the avatar.
12 |
A volunteer site has a welcoming page for new volunteers. In it there is an application form. On the right side of the page there an interactive multimedia file with an avatar that explains all the features and sections of the application form.
13 |
14 |
Tests
15 |
Procedure
16 |
17 |
Check that there is an assistant in the Web page.
18 |
Check that the assistant provides information to help understand the content of the page.
For moving, blinking, scrolling, or auto-updating information, all of the following are true:
8 |
9 |
10 |
11 |
12 |
Moving, blinking, scrolling
13 |
14 |
15 |
16 |
For any moving, blinking or scrolling information that (1) starts automatically, (2)
17 | lasts more than five seconds, and (3) is presented in parallel with other content,
18 | there is a mechanism for the user to pause, stop, or hide it unless the movement, blinking, or scrolling is part of an activity
19 | where it is essential; and
20 |
21 |
22 |
23 |
24 |
Auto-updating
25 |
26 |
27 |
28 |
For any auto-updating information that (1) starts automatically and (2) is presented
29 | in parallel with other content, there is a mechanism for the user to pause, stop,
30 | or hide it or to control the frequency of the update unless the auto-updating is part
31 | of an activity where it is essential.
32 |
33 |
34 |
35 |
36 |
37 |
38 |
For requirements related to flickering or flashing content, refer to Guideline 2.3.
39 |
40 |
41 |
Since any content that does not meet this success criterion can interfere with a user's
42 | ability to use the whole page, all content on the Web page (whether it is used to
43 | meet other success criteria or not) must meet this success criterion. See Conformance Requirement 5: Non-Interference.
44 |
45 |
46 |
Content that is updated periodically by software or that is streamed to the user agent
47 | is not required to preserve or present information that is generated or received between
48 | the initiation of the pause and resuming presentation, as this may not be technically
49 | possible, and in many situations could be misleading to do so.
50 |
51 |
52 |
An animation that occurs as part of a preload phase or similar situation can be considered
53 | essential if interaction cannot occur during that phase for all users and if not indicating
54 | progress could confuse users or cause them to think that content was frozen or broken.
55 |
56 |
57 |
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/techniques/general/G205.html:
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1 | Including a text cue for colored form control labels
Including a text cue for colored form control labels
ID: G205
Technology: general
Type: Technique
When to Use
2 |
All technologies that support color and text.
3 |
Description
4 |
The objective of this technique is to combine color and text or character cues to convey information. Most users can quickly scan the content to locate information conveyed by using color differences. Users who cannot see color can look or listen for text cues; people using Braille displays or other tactile interfaces can detect text cues by touch.
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The text cue must be included as part of the programmatically determinable name for the control.
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Examples
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Example 1: Required fields in an HTML form
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Description
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The instructions for an online form say, "Required fields are shown in red and marked with (required)." The cue "(required)" is included within the label element.