In WCAG 2, the Guidelines are provided for framing and understanding the success criteria under them but are not used for conformance to WCAG. Guideline 1.1 applies directly as written.

(Level A)

All non-text content that is presented to the user has a text alternative that serves the equivalent purpose, except for the situations listed below.

Controls, Input

If non-text content is a control or accepts user input, then it has a name that describes its purpose. (Refer to Success Criterion 4.1.2 for additional requirements for controls and content that accepts user input.)

Time-Based Media

If non-text content is time-based media, then text alternatives at least provide descriptive identification of the non-text content. (Refer to Guideline 1.2 for additional requirements for media.)

Test

If non-text content is a test or exercise that would be invalid if presented in text, then text alternatives at least provide descriptive identification of the non-text content.

Sensory

If non-text content is primarily intended to create a specific sensory experience, then text alternatives at least provide descriptive identification of the non-text content.

CAPTCHA

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

Decoration, Formatting, Invisible

If non-text content is pure decoration, is used only for visual formatting, or is not presented to users, then it is implemented in a way that it can be ignored by assistive technology.

In WCAG 2, the Guidelines are provided for framing and understanding the success criteria under them but are not used for conformance to WCAG. Guideline 1.2 applies directly as written.

(Level A)

For prerecorded audio-only and prerecorded video-only media, the following are true, except when the audio or video is a media alternative for text and is clearly labeled as such:

Prerecorded Audio-only

An alternative for time-based media is provided that presents equivalent information for prerecorded audio-only content.

Prerecorded Video-only

Either an alternative for time-based media or an audio track is provided that presents equivalent information for prerecorded video-only content.

(Level A)

Captions are provided for all prerecorded audio content in synchronized media, except when the media is a media alternative for text and is clearly labeled as such.

(Level A)

An alternative for time-based media or audio description of the prerecorded video content is provided for synchronized media, except when the media is a media alternative for text and is clearly labeled as such.

(Level AA)

Captions are provided for all live audio content in synchronized media.

(Level AA)

Audio description is provided for all prerecorded video content in synchronized media.

In WCAG 2, the Guidelines are provided for framing and understanding the success criteria under them but are not used for conformance to WCAG. Guideline 1.3 applies directly as written.

(Level A)

Information, structure, and relationships conveyed through presentation can be programmatically determined or are available in text.

(Level A)

When the sequence in which content is presented affects its meaning, a correct reading sequence can be programmatically determined.

(Level A)

Instructions provided for understanding and operating content do not rely solely on sensory characteristics of components such as shape, color, size, visual location, orientation, or sound.

Note

For requirements related to color, refer to Guideline 1.4.

(Level AA)

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.

Note

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 content is not necessarily restricted to landscape or portrait display orientation.

(Level AA)

The purpose of each input field collecting information about the user can be programmatically determined when:

• The input field serves a purpose identified in the Input Purposes for user interface components section; and
• The content is implemented using technologies with support for identifying the expected meaning for form input data.

In WCAG 2, the Guidelines are provided for framing and understanding the success criteria under them but are not used for conformance to WCAG. Guideline 1.4 applies directly as written.

(Level A)

Color is not used as the only visual means of conveying information, indicating an action, prompting a response, or distinguishing a visual element.

Note

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.

(Level A)

If any audio on a Web page plays automatically for more than 3 seconds, either a mechanism is available to pause or stop the audio, or a mechanism is available to control audio volume independently from the overall system volume level.

Note

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

(Level AA)

The visual presentation of text and images of text has a contrast ratio of at least 4.5:1, except for the following:

Large Text

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

Incidental

Text or images of text that are part of an inactive user interface component, that are pure decoration, that are not visible to anyone, or that are part of a picture that contains significant other visual content, have no contrast requirement.

Logotypes

Text that is part of a logo or brand name has no contrast requirement.

(Level AA)

Except for captions and images of text, text can be resized without assistive technology up to 200 percent without loss of content or functionality.

(Level AA)

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:

Customizable

The image of text can be visually customized to the user's requirements;

Essential

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

Note

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

(Level AA)

Content can be presented without loss of information or functionality, and without requiring scrolling in two dimensions for:

• Vertical scrolling content at a width equivalent to 320 CSS pixels;
• Horizontal scrolling content at a height equivalent to 256 CSS pixels.

Except for parts of the content which require two-dimensional layout for usage or meaning.

Note 1

320 CSS pixels is equivalent to a starting viewport width of 1280 CSS pixels wide at 400% zoom. For web content which is designed to scroll horizontally (e.g., with vertical text), 256 CSS pixels is equivalent to a starting viewport height of 1024 CSS pixels at 400% zoom.

Note 2

Examples of content which requires two-dimensional layout are images required for understanding (such as maps and diagrams), video, games, presentations, data tables (not individual cells), and interfaces where it is necessary to keep toolbars in view while manipulating content. It is acceptable to provide two-dimensional scrolling for such parts of the content.

(Level AA)

The visual presentation of the following have a contrast ratio of at least 3:1 against adjacent color(s):

User Interface Components

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;

Graphical Objects

Parts of graphics required to understand the content, except when a particular presentation of graphics is essential to the information being conveyed.

(Level AA)

In content implemented using markup languages that support the following text style properties, no loss of content or functionality occurs by setting all of the following and by changing no other style property:

• Line height (line spacing) to at least 1.5 times the font size;
• Spacing following paragraphs to at least 2 times the font size;
• Letter spacing (tracking) to at least 0.12 times the font size;
• Word spacing to at least 0.16 times the font size.

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.

Note 1

Content is not required to use these text spacing values. The requirement is to ensure that when a user overrides the authored text spacing, content or functionality is not lost.

Note 2

Writing systems for some languages use different text spacing settings, such as paragraph start indent. Authors are encouraged to follow locally available guidance for improving readability and legibility of text in their writing system.

(Level AA)

Where receiving and then removing pointer hover or keyboard focus triggers additional content to become visible and then hidden, the following are true:

Dismissible

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;

Hoverable

If pointer hover can trigger the additional content, then the pointer can be moved over the additional content without the additional content disappearing;

Persistent

The additional content remains visible until the hover or focus trigger is removed, the user dismisses it, or its information is no longer valid.

Exception: The visual presentation of the additional content is controlled by the user agent and is not modified by the author.

Note 1

Examples of additional content controlled by the user agent include browser tooltips created through use of the HTML title attribute [HTML].

Note 2

Custom tooltips, sub-menus, and other nonmodal popups that display on hover and focus are examples of additional content covered by this criterion.

Note 3

This criterion applies to content that appears in addition to the triggering component itself. Since hidden components that are made visible on keyboard focus (such as links used to skip to another part of a page) do not present additional content they are not covered by this criterion.

In WCAG 2, the Guidelines are provided for framing and understanding the success criteria under them but are not used for conformance to WCAG. Guideline 2.1 applies directly as written.

(Level A)

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

Note 1

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

Note 2

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

(Level A)

If keyboard focus can be moved to a component of the page using a keyboard interface, then focus can be moved away from that component using only a keyboard interface, and, if it requires more than unmodified arrow or tab keys or other standard exit methods, the user is advised of the method for moving focus away.

Note

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

(Level A)

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:

Turn off

A mechanism is available to turn the shortcut off;

Remap

A mechanism is available to remap the shortcut to include one or more non-printable keyboard keys (e.g., Ctrl, Alt);

Active only on focus

The keyboard shortcut for a user interface component is only active when that component has focus.

In WCAG 2, the Guidelines are provided for framing and understanding the success criteria under them but are not used for conformance to WCAG. Guideline 2.2 applies directly as written.

(Level A)

For each time limit that is set by the content, at least one of the following is true:

Turn off

The user is allowed to turn off the time limit before encountering it; or

Adjust

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

Extend

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

Real-time Exception

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

Essential Exception

The time limit is essential and extending it would invalidate the activity; or

20 Hour Exception

The time limit is longer than 20 hours.

Note

This success criterion helps ensure that users can complete tasks without unexpected changes in content or context that are a result of a time limit. This success criterion should be considered in conjunction with Success Criterion 3.2.1, which puts limits on changes of content or context as a result of user action.

(Level A)

For moving, blinking, scrolling, or auto-updating information, all of the following are true:

Moving, blinking, scrolling

For any moving, blinking or scrolling information that (1) starts automatically, (2) lasts more than five seconds, and (3) is presented in parallel with other content, there is a mechanism for the user to pause, stop, or hide it unless the movement, blinking, or scrolling is part of an activity where it is essential; and

Auto-updating

For any auto-updating information that (1) starts automatically and (2) is presented in parallel with other content, there is a mechanism for the user to pause, stop, or hide it or to control the frequency of the update unless the auto-updating is part of an activity where it is essential.

Note 1

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

Note 2

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

Note 3

Content that is updated periodically by software or that is streamed to the user agent is not required to preserve or present information that is generated or received between the initiation of the pause and resuming presentation, as this may not be technically possible, and in many situations could be misleading to do so.

Note 4

An animation that occurs as part of a preload phase or similar situation can be considered essential if interaction cannot occur during that phase for all users and if not indicating progress could confuse users or cause them to think that content was frozen or broken.

In WCAG 2, the Guidelines are provided for framing and understanding the success criteria under them but are not used for conformance to WCAG. Guideline 2.3 applies directly as written.

(Level A)

Web pages do not contain anything that flashes more than three times in any one second period, or the flash is below the general flash and red flash thresholds.

Note

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

In WCAG 2, the Guidelines are provided for framing and understanding the success criteria under them but are not used for conformance to WCAG. Guideline 2.4 applies directly as written.

(Level A)

A mechanism is available to bypass blocks of content that are repeated on multiple Web pages.

(Level A)

Web pages have titles that describe topic or purpose.

(Level A)

If a Web page can be navigated sequentially and the navigation sequences affect meaning or operation, focusable components receive focus in an order that preserves meaning and operability.

(Level A)

The purpose of each link can be determined from the link text alone or from the link text together with its programmatically determined link context, except where the purpose of the link would be ambiguous to users in general.

(Level AA)

More than one way is available to locate a Web page within a set of Web pages except where the Web Page is the result of, or a step in, a process.

(Level AA)

Headings and labels describe topic or purpose.

(Level AA)

Any keyboard operable user interface has a mode of operation where the keyboard focus indicator is visible.

(Level AA)

When a user interface component receives keyboard focus, the component is not entirely hidden due to author-created content.

Note 1

Where content in a configurable interface can be repositioned by the user, then only the initial positions of user-movable content are considered for testing and conformance of this Success Criterion.

Note 2

Content opened by the user may obscure the component receiving focus. If the user can reveal the focused component without advancing the keyboard focus, the component with focus is not considered hidden due to author-created content.

In WCAG 2, the Guidelines are provided for framing and understanding the success criteria under them but are not used for conformance to WCAG. Guideline 2.5 applies directly as written.

(Level A)

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.

Note

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).

(Level A)

For functionality that can be operated using a single pointer, at least one of the following is true:

No Down-Event

The down-event of the pointer is not used to execute any part of the function;

Abort or Undo

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;

Up Reversal

The up-event reverses any outcome of the preceding down-event;

Essential

Completing the function on the down-event is essential.

Note 1

Functions that emulate a keyboard or numeric keypad key press are considered essential.

Note 2

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).

(Level A)

For user interface components with labels that include text or images of text, the name contains the text that is presented visually.

Note

A best practice is to have the text of the label at the start of the name.

(Level A)

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:

Supported Interface

The motion is used to operate functionality through an accessibility supported interface;

Essential

The motion is essential for the function and doing so would invalidate the activity.

(Level AA)

All functionality that uses a dragging movement for operation can be achieved by a single pointer without dragging, unless dragging is essential or the functionality is determined by the user agent and not modified by the author.

Note

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).

(Level AA)

The size of the target for pointer inputs is at least 24 by 24 CSS pixels, except where:

• Spacing: Undersized targets (those less than 24 by 24 CSS pixels) are positioned so that if a 24 CSS pixel diameter circle is centered on the bounding box of each, the circles do not intersect another target or the circle for another undersized target;
• Equivalent: The function can be achieved through a different control on the same page that meets this criterion;
• Inline: The target is in a sentence or its size is otherwise constrained by the line-height of non-target text;
• User agent control: The size of the target is determined by the user agent and is not modified by the author;
• Essential: A particular presentation of the target is essential or is legally required for the information being conveyed.

Note 1

Targets that allow for values to be selected spatially based on position within the target are considered one target for the purpose of the success criterion. Examples include sliders, color pickers displaying a gradient of colors, or editable areas where you position the cursor.

Note 2

For inline targets the line-height should be interpreted as perpendicular to the flow of text. For example, in a language displayed vertically, the line-height would be horizontal.

In WCAG 2, the Guidelines are provided for framing and understanding the success criteria under them but are not used for conformance to WCAG. Guideline 3.1 applies directly as written.

(Level A)

The default human language of each Web page can be programmatically determined.

(Level AA)

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 or phrases that have become part of the vernacular of the immediately surrounding text.

In WCAG 2, the Guidelines are provided for framing and understanding the success criteria under them but are not used for conformance to WCAG. Guideline 3.2 applies directly as written, replacing “web pages” with “non-web documents or software”.

With this substitution, it would read:

Guideline 3.2 Predictable: Make [non-web documents or software] appear and operate in predictable ways.

(Level A)

When any user interface component receives focus, it does not initiate a change of context.

(Level A)

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.

(Level AA)

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.

(Level AA)

Components that have the same functionality within a set of Web pages are identified consistently.

(Level A)

If a Web page contains any of the following help mechanisms, and those mechanisms are repeated on multiple Web pages within a set of Web pages, they occur in the same order relative to other page content, unless a change is initiated by the user:

• Human contact details;
• Human contact mechanism;
• Self-help option;
• A fully automated contact mechanism.

Note 1

Help mechanisms may be provided directly on the page, or may be provided via a direct link to a different page containing the information.

Note 2

For this Success Criterion, "the same order relative to other page content" can be thought of as how the content is ordered when the page is serialized. The visual position of a help mechanism is likely to be consistent across pages for the same page variation (e.g., CSS break-point). The user can initiate a change, such as changing the page's zoom or orientation, which may trigger a different page variation. This criterion is concerned with relative order across pages displayed in the same page variation (e.g., same zoom level and orientation).

In WCAG 2, the Guidelines are provided for framing and understanding the success criteria under them but are not used for conformance to WCAG. Guideline 3.3 applies directly as written.

(Level A)

If an input error is automatically detected, the item that is in error is identified and the error is described to the user in text.

(Level A)

Labels or instructions are provided when content requires user input.

(Level AA)

If an input error is automatically detected and suggestions for correction are known, then the suggestions are provided to the user, unless it would jeopardize the security or purpose of the content.

(Level AA)

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 the following is true:

Reversible

Submissions are reversible.

Checked

Data entered by the user is checked for input errors and the user is provided an opportunity to correct them.

Confirmed

A mechanism is available for reviewing, confirming, and correcting information before finalizing the submission.

(Level A)

Information previously entered by or provided to the user that is required to be entered again in the same process is either:

• auto-populated, or
• available for the user to select.

Except when:

• re-entering the information is essential,
• the information is required to ensure the security of the content, or
• previously entered information is no longer valid.

(Level AA)

A cognitive function test (such as remembering a password or solving a puzzle) is not required for any step in an authentication process unless that step provides at least one of the following:

Alternative

Another authentication method that does not rely on a cognitive function test.

Mechanism

A mechanism is available to assist the user in completing the cognitive function test.

Object Recognition

The cognitive function test is to recognize objects.

Personal Content

The cognitive function test is to identify non-text content the user provided to the Web site.

Note 1

"Object recognition" and "Personal content" may be represented by images, video, or audio.

Note 2

Examples of mechanisms that satisfy this criterion include:

1. support for password entry by password managers to reduce memory need, and
2. copy and paste to reduce the cognitive burden of re-typing.

In WCAG 2, the Guidelines are provided for framing and understanding the success criteria under them but are not used for conformance to WCAG. Guideline 4.1 applies directly as written, replacing “user agents, including assistive technologies” with “assistive technologies and accessibility features of software”.

With this substitution, it would read:

Guideline 4.1 Compatible: Maximize compatibility with current and future [assistive technologies and accessibility features of software].

(Level A)

In content implemented using markup languages, elements have complete start and end tags, elements are nested according to their specifications, elements do not contain duplicate attributes, and any IDs are unique, except where the specifications allow these features.

Note 1

This Success Criterion should be considered as always satisfied for any content using HTML or XML.

Note 2

Since this criterion was written, the HTML Living Standard has adopted specific requirements governing how user agents must handle incomplete tags, incorrect element nesting, duplicate attributes, and non-unique IDs. [HTML]

Although the HTML Standard treats some of these cases as non-conforming for authors, it is considered to "allow these features" for the purposes of this Success Criterion because the specification requires that user agents support handling these cases consistently. In practice, this criterion no longer provides any benefit to people with disabilities in itself.

Issues such as missing roles due to inappropriately nested elements or incorrect states or names due to a duplicate ID are covered by different Success Criteria and should be reported under those criteria rather than as issues with 4.1.1.

(Obsolete and removed)

Note

This criterion was originally adopted to address problems that assistive technology had directly parsing HTML. Assistive technology no longer has any need to directly parse HTML. Consequently, these problems either no longer exist or are addressed by other criteria. This criterion no longer has utility and is removed.

(Level A)

For all user interface components (including but not limited to: form elements, links and components generated by scripts), the name and role can be programmatically determined; states, properties, and values that can be set by the user can be programmatically set; and notification of changes to these items is available to user agents, including assistive technologies.

Note

This success criterion is primarily for Web authors who develop or script their own user interface components. For example, standard HTML controls already meet this success criterion when used according to specification.

(Level AA)

In content implemented using markup languages, status messages can be programmatically determined through role or properties such that they can be presented to the user by assistive technologies without receiving focus.

This applies directly as written and as described in the WCAG 2 glossary, replacing “browsers and other user agents” with “user agents or other software”, replacing “user agents” with “user agents or other software”, replacing “web content technology” with “non-web document or software technology”, adding “or other software extension” after “plug-in”, and replacing all five of the Notes with a single Note: “Note: The concepts behind the five Notes and in Understanding Accessibility Supported are applicable to web technologies. The same or similar factors are applicable for non-web technologies.”

With these substitutions and addition, it would read:

accessibility supported

supported by users' assistive technologies as well as the accessibility features in [user agents or other software]

To qualify as an accessibility-supported use of a [non-web document or software] technology (or feature of a technology), both 1 and 2 must be satisfied for a [non-web document or software] technology (or feature):

1. The way that the [non-web document or software technology] is used must be supported by users' assistive technology (AT). This means that the way that the technology is used has been tested for interoperability with users' assistive technology in the human language(s) of the content,

   AND

2. The [non-web document or software] technology must have accessibility-supported user agents [or other software] that are available to users. This means that at least one of the following four statements is true:

   1. The technology is supported natively in widely-distributed user agents [or other software] that are also accessibility supported (such as HTML and CSS);

      OR

   2. The technology is supported in a widely-distributed plug-in [or other software extension] that is also accessibility supported;

      OR

   3. The content is available in a closed environment, such as a university or corporate network, where the user agent [or other software] required by the technology and used by the organization is also accessibility supported;

      OR

   4. The user agent(s) that support the technology are accessibility supported and are available for download or purchase in a way that:

      • does not cost a person with a disability any more than a person without a disability and

      • is as easy to find and obtain for a person with a disability as it is for a person without disabilities.

Note (Added)

[The concepts behind the five Notes and in Understanding Accessibility Supported are applicable to web technologies. The same or similar factors are applicable for non-web technologies.]

This applies directly as written and as described in the WCAG 2 glossary, replacing “Web page” with “non-web document or software”.

With this substitution, it would read:

ambiguous to users in general

the purpose cannot be determined from the link and all information of the [non-web document or software] presented to the user simultaneously with the link (i.e., readers without disabilities would not know what a link would do until they activated it)

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

This applies directly as written and as described in the WCAG 2 glossary, replacing “acts as a user agent” with “acts stand-alone”, replacing “a mainstream user agent” with “mainstream information and communication technologies (ICT)” (later “mainstream ICT”), and replacing “Web content” with “content”.

With these substitutions, it would read:

assistive technology (as used in this document)

hardware and/or software that acts [stand-alone], or along with [mainstream information and communication technologies (ICT)], to provide functionality to meet the requirements of users with disabilities that go beyond those offered by [mainstream ICT]

Note 1

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

Note 2

Assistive technologies often communicate data and messages with [mainstream ICTs] by using and monitoring APIs.

Note 3

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

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

• screen magnifiers, and other visual reading assistants, which are used by people with visual, perceptual and physical print disabilities to change text font, size, spacing, color, synchronization with speech, etc. in order to improve the visual readability of rendered text and images;
• screen readers, which are used by people who are blind to read textual information through synthesized speech or braille;
• text-to-speech software, which is used by some people with cognitive, language, and learning disabilities to convert text into synthetic speech;
• speech recognition software, which may be used by people who have some physical disabilities;
• alternative keyboards, which are used by people with certain physical disabilities to simulate the keyboard (including alternate keyboards that use head pointers, single switches, sip/puff and other special input devices.);
• alternative pointing devices, which are used by people with certain physical disabilities to simulate mouse pointing and button activations.

This applies directly as written and as described in the WCAG 2 glossary, replacing “page” with “non-web document or content presented by software”.

With these substitutions, it would read:

changes of context

major changes that, if made without user awareness, can disorient users who are not able to view the entire non-web document or content presented by software] simultaneously

Changes in context include changes of:

1. user agent;

2. viewport;

3. focus;

4. content that changes the meaning of the [non-web document or content presented by software].

Note 1

A change of content is not always a change of context. Changes in content, such as an expanding outline, dynamic menu, or a tab control do not necessarily change the context, unless they also change one of the above (e.g., focus).

Example: Opening a new window, moving focus to a different component, going to a new page (including anything that would look to a user as if they had moved to a new page) or significantly re-arranging the content of a page are examples of changes of context.

Note 2 (Added)

A change in the user agent might include bringing up a new window, or might be a significant change in the menus and/or toolbars that are displayed and available for interacting with some portion of the document.

This applies directly as written and as described in the WCAG 2 glossary, replacing “Web sites” with “Web sites, non-web documents, and software”.

With this substitution, it would read:

cognitive function test

A task that requires the user to remember, manipulate, or transcribe information. Examples include, but are not limited to:

memorization, such as remembering a username, password, set of characters, images, or patterns. The common identifiers name, e-mail, and phone number are not considered cognitive function tests as they are personal to the user and consistent across [Web sites, non-web documents, and software];

• transcription, such as typing in characters;
• use of correct spelling;
• performance of calculations;
• solving of puzzles.

The guidance in this document does not use the term “conforming alternate version”.

See the section Comments on Conformance.

See the guidance on content in the Key Terms section.

This applies directly as written and as described in the WCAG 2 glossary.

This applies directly as written and as described in the WCAG 2 glossary.

This applies directly as written and as described in the WCAG 2 glossary.  

This applies directly as written and as described in the WCAG 2 glossary.

This applies directly as written and as described in the WCAG 2 glossary, replacing “Web page” with “non-web document or software”.

With this substitution, it would read:

input error

information provided by the user that is not accepted

Note

This includes:

1. Information that is required by the [non-web document or software] but omitted by the user

2. Information that is provided by the user but that falls outside the required data format or values

This applies directly as written and as described in the WCAG 2 glossary.

This applies directly as written and as described in the WCAG 2 glossary.

This applies directly as written and as described in the WCAG 2 glossary, replacing “Web Content” with “content” and adding “or by accessibility features of software” after “assistive technology” in Note 1.

With this substitution and addition, it would read:

label

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

Note 1

A label is presented to all users whereas the name may be hidden and only exposed by assistive technology [or by accessibility features of software]. In many (but not all) cases the name and the label are the same.

Note 2

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

This applies directly as written and as described in the WCAG 2 glossary, replacing “user agent” with “user agent or non-web software” in Note 3 and “browsers” with "browsers, user agents, or platform software” in Note 4.

With this substitution and addition, it would read:

large scale (text)

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

Note 1

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

Note 2

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

Note 3

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

Note 4

The actual size of the character that a user sees is dependent both on the author-defined size and the user's display, [user agent or non-web software] settings. For many mainstream body text fonts, 14 and 18 point is roughly equivalent to 1.2 and 1.5 em or to 120% or 150% of the default size for body text (assuming that the body font is 100%), but authors would need to check this for the particular fonts in use. When fonts are defined in relative units, the actual point size is calculated by the [user agent or [non-web software] for display. The point size should be obtained from the [user agent or non-web software], or calculated based on font metrics as the [user agent or non-web software] does, when evaluating this success criterion. Users who have low vision would be responsible for choosing appropriate settings.

Note 5

When using text without specifying the font size, the smallest font size used on major [browsers, user agents, or platform software] for unspecified text would be a reasonable size to assume for the font. If a level 1 heading is rendered in 14pt bold or higher on major [browsers, user agents, or platform software], then it would be reasonable to assume it is large text. Relative scaling can be calculated from the default sizes in a similar fashion.

Note 6 (Added)

When evaluating non-web documents and software, 1 point means 1.333 CSS pixels.

This applies directly as written and as described in the WCAG 2 glossary, replacing “Web content” with “content” and adding “or by accessibility features of software” after “assistive technology” in Note 1.

With this substitution and addition, it would read:

name

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

Note 1

The name may be hidden and only exposed by assistive technology [or by accessibility features of software], whereas a label is presented to all users. In many (but not all) cases, the label and the name are the same.

Note 2

This is unrelated to the name attribute in HTML.

Example: For non-web software, “AccessibleName” (or the corresponding term used in different APIs) of the Accessibility API of the platform is an example of such a name.

This applies directly as written and as described in the WCAG 2 glossary, replacing “user agents, including assistive technologies", with “assistive technologies and accessibility features of software” and adding “and accessibility features of software” after “assistive technology”.

With this substitution and addition, it would read:

programmatically determined (programmatically determinable)

determined by software from author-supplied data provided in a way that different [assistive technologies and accessibility features of software] can extract and present this information to users in different modalities

Example 1: Determined in a markup language from elements and attributes that are accessed directly by commonly available assistive technology [and accessibility features of software].

Example 2: Determined from technology-specific data structures in a non-markup language and exposed to assistive technology [and accessibility features of software] via an accessibility API that is supported by commonly available assistive technology [and accessibility features of software].

Note (Added)

Software typically enables content to be programmatically determined through the use of accessibility services of platform software. Non-web documents typically enable content to be programmatically determined through the use of accessibility services of the user agent.

This applies directly as written and as described in the WCAG 2 glossary, replacing “user agents, including assistive technologies” with “assistive technologies and accessibility features of software”.

With this substitution, it would read:

programmatically set

set by software using methods that are supported by [assistive technologies and accessibility features of software]

This applies directly as written and as described in the WCAG 2 glossary, replacing “Web content” with “content”.

With this substitution, it would read:

relative luminance

the relative brightness of any point in a colorspace, normalized to 0 for darkest black and 1 for lightest white

Note 1

For the sRGB colorspace, the relative luminance of a color is defined as L = 0.2126 * R + 0.7152 * G + 0.0722 * B where R, G and B are defined as:

• if RsRGB <= 0.04045 then R = RsRGB/12.92 else R = ((RsRGB+0.055)/1.055) ^ 2.4
• if GsRGB <= 0.04045 then G = GsRGB/12.92 else G = ((GsRGB+0.055)/1.055) ^ 2.4
• if BsRGB <= 0.04045 then B = BsRGB/12.92 else B = ((BsRGB+0.055)/1.055) ^ 2.4

and RsRGB, GsRGB, and BsRGB are defined as:

• RsRGB = R8bit/255
• GsRGB = G8bit/255
• BsRGB = B8bit/255

The “^” character is the exponentiation operator. (Formula taken from [sRGB].)

Note 2

Before May 2021 the value of 0.04045 in the definition was different (0.03928). It was taken from an older version of the specification and has been updated. It has no practical effect on the calculations in the context of these guidelines.

Note 3

Almost all systems used today to view [content] assume sRGB encoding. Unless it is known that another color space will be used to process and display the content, authors should evaluate using sRGB colorspace. If using other color spaces, see Understanding Success Criterion 1.4.3.

Note 4

If dithering occurs after delivery, then the source color value is used. For colors that are dithered at the source, the average values of the colors that are dithered should be used (average R, average G, and average B).

Note 5

Tools are available that automatically do the calculations when testing contrast and flash.

Note 6

A separate page giving the relative luminance definition using MathML to display the formulas is available.

Note 7 (Added)

Because relative luminance is defined such that it cannot directly apply to hardware, please note the text in the introduction which reads: “This document does not comment on hardware aspects of products, because the basic constructs on which WCAG 2 is built do not apply to these.”

This applies directly as written and as described in the WCAG 2 glossary, replacing “Web content” with “content”.

With this substitution, it would read:

role

text or number by which software can identify the function of a component within [content]

Example: A number that indicates whether an image functions as a hyperlink, command button, or check box.

Note (Added)

“AccessibleRole” (or the corresponding term used in different APIs) of the Accessibility API of the platform is an example of such a role.

This applies directly as written and as described in the WCAG 2 glossary, adding a second example (and numbering the first).

With this addition, it would read:

same functionality

same result when used

Example 1: A submit “search” button on one Web page and a “find” button on another Web page may both have a field to enter a term and list topics in the Web site related to the term submitted. In this case, they would have the same functionality but would not be labeled consistently.

Example 2: A ribbon icon that saves the document that looks like an arrow pointing into a folder in one case, and an arrow pointing into a hard drive in another. In this case as well, they would have the same functionality but would not be labeled consistently.

This applies directly as written and as described in the WCAG 2 glossary, replacing “page” with “non-web document or software”.

With this substitution, it would read:

satisfies a success criterion

the success criterion does not evaluate to 'false' when applied to the [non-web document or software]

See the guidance on set of documents and set of software programs in the Key Terms section.

This applies directly as written and as described in the WCAG 2 glossary, replacing “a Web page” with “non-web documents or software” and replacing “collection of Web pages” with “set of documents or set of software programs”.

With these substitutions, it would read:

structure

1. The way the parts of [non-web documents or software] are organized in relation to each other; and

2. The way a [set of documents or set of software programs] is organized

This applies directly as written and as described in the WCAG 2 glossary, replacing “user agent(s)” with “user agent(s) or platform software”, "web content" with "content", replacing "in-line styles, author style sheets" with "programmatically-set styles", and replacing "user agent interface settings" with "user agent, platform software or other software interface settings, or".

With these substitutions, it would read:

style property

property whose value determines the presentation (e.g. font, color, size, location, padding, volume, synthesized speech prosody) of content elements as they are rendered (e.g. onscreen, via loudspeaker, via braille display) by [user agents or platform software]

Style properties can have several origins:

• [User agent or platform software] default styles: The default style property values applied in the absence of any author or user styles. Some [content] technologies specify a default rendering, others do not;
• Author styles: Style property values that are set by the author as part of the content (e.g. [programmatically-set styles]);
• User styles: Style property values that are set by the user (e.g. via [user agent, platform software or other software interface settings, or] user style sheets)

This applies directly as written and as described in the WCAG 2 glossary, replacing “page” with “non-web document or content presented by software”.

With this substitution, it would read:

target

region of the display that will accept a pointer action, such as the interactive area of a user interface component

Note

If two or more 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 [non-web document or content presented by software].

This applies directly as written and as described in the WCAG 2 glossary, replacing “web content” with “non-web document or software”, “user agents” with “user agents or other software”, removing the notes, and replacing the example with “Example: Some common examples of non-web document and software technologies include ODF, OOXML, Java, and C++.”

With these substitutions, it would read:

technology ([non-web document or software])

mechanism for encoding instructions to be rendered, played or executed by [user agents or other software].

Example: Some common examples of [non-web document and software technologies include ODF, OOXML, Java, and C++].

This applies directly as written and as described in the WCAG 2 glossary.  

See the guidance on user agent in the Key Terms section.

This applies directly as written and as described in the WCAG 2 glossary, replacing the example with “Example: A software program has 2 controls: a text field for entering a file name and a drop down list box for choosing a folder. Each is a user interface component with a name that is settable by the software.”

With this substitution, it would read:

user interface component

a part of the content that is perceived by users as a single control for a distinct function

Note 1

Multiple user interface components may be implemented as a single programmatic element. "Components" here is not tied to programming techniques, but rather to what the user perceives as separate controls.

Note 2

User interface components include form elements and links as well as components generated by scripts.

Note 3

What is meant by "component" or "user interface component" here is also sometimes called "user interface element".

Example: A software program has 2 controls: a text field for entering a file name and a drop down list box for choosing a folder. Each is a user interface component with a name that is settable by the software.

This applies directly as written and as described in the WCAG 2 glossary, replacing “user agent” with “software”.

With this substitution, it would read:

viewport

object in which the [software] presents content

Note 1

The [software] presents content through one or more viewports. Viewports include windows, frames, loudspeakers, and virtual magnifying glasses. A viewport may contain another viewport (e.g., nested frames). Interface components created by the [software] such as prompts, menus, and alerts are not viewports.

Note 2

This definition is based on User Agent Accessibility Guidelines 1.0 Glossary [UAAG10].

This applies directly as written and as described in the WCAG 2 glossary.