W3C

Web Content Accessibility Guidelines 2.0

W3C Working Draft 24 April 2002

This version:
http://www.w3.org/WAI/GL/WCAG20/WD-WCAG20-20020424.html
Latest version:
http://www.w3.org/WAI/GL/WCAG20/
Previous version:
Restructuring proposal sent as attachment.
Previous draft to restructuring proposal:
http://www.w3.org/WAI/GL/WCAG20/WD-WCAG20-20011026.html
Editors:
Wendy Chisholm, W3C
Jason White, University of Melbourne
Gregg Vanderheiden, Trace R&D Center

Abstract

W3C published the Web Content Accessibility Guidelines 1.0 (WCAG 1.0) as a Recommendation in May 1999. This Working Draft for version 2.0 builds on WCAG 1.0. It has the same aim: explain how to make Web content accessible to people with disabilities. Incorporating feedback on WCAG 1.0, this Working Draft of version 2.0 focuses on checkpoints. It attempts to apply checkpoints to a wider range of technologies and to use wording that may be understood by a more varied audience.

Status of this document

This document is prepared by the Web Content Accessibility Guidelines Working Group (WCAG WG) to show how more generalized (less HTML-specific) WCAG checkpoints might read. This draft is not based on consensus of the WCAG Working Group nor has it gone through W3C process. This Working Draft in no way supersedes WCAG 1.0.

Please refer to "Issue Tracking for WCAG 2.0" for a list of open issues related to this Working Draft. The "History of Changes to WCAG 2.0 Working Drafts" is also available.

This is a draft document and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use W3C Working Drafts as reference material or to cite them as other than "work in progress". A list of current W3C Recommendations and other technical documents is available.

Please send comments on this document to w3c-wai-gl@w3.org. The archives for this list are publicly available.


Table of Contents


Introduction

Purpose

This document outlines design principles for creating accessible Web sites. When these principles are ignored, individuals with disabilities may not be able to access the content at all, or they may be able to do so only with great difficulty. When these principles are employed, they also make Web content accessible to a variety of Web-enabled devices, such as phones, handheld devices, kiosks, network appliances, etc. By making content accessible to a variety of devices, the content is now accessible to people in a variety of situations.

The design principles in this document represent broad concepts that apply to all Web-based content. They are not specific to HTML, XML, or any other technology. This approach was taken so that the design principles could be applied to a variety of situations and technologies, including those that do not yet exist.

How to read this document

In order to facilitate understanding of the guidelines and to help people focus in on just the parts they need, the guidelines are presented as a set of interrelated documents. There are basically 3 layers to the guidelines information.

1 - Top layer - Overview of Design Principles, Guidelines, Checkpoints

The top layer is titled "Web Content Accessibility Guidelines 2.0". It is the document you are currently reading. This document provides:

  1. An introduction
  2. The 5 major Guidelines for accessibility (Perceivable, Operable, Orientation/Navigation, Comprehension and Technology Robust)
  3. The (non-technology specific) checkpoints for each guideline (21 in Toto).
  4. Success criteria (normative), and definitions, benefits and examples (all non-normative) for each checkpoint
  5. An appendix containing definitions and other support information.

2 - Technology Specific Guidelines

In addition to the general guidelines, there are a series of Technology Specific Guidelines documents. These documents provide information on what is required when using different technologies in order to meet the WCAG 2.0 access guidelines. These documents are also normative.

[are we doing this level now?]

3 - Bottom layer - Technology-specific application information

In separate Techniques Documents are code examples, screen shots, and other information specific to a technology. These documents are non-normative and do not contain requirements. Rather they contain different strategies for meeting the requirements as well as the current preferred approaches where they exist. Examples include:

(These will become active links as the corresponding working drafts are published)

Issue: it has been proposed that we provide multiple, automatically generated "views" of the guidelines document for different purposes, using XSLT. What are the different "views" of the document that we should make available? Should we also have versions that include techniques or technology-specific success criteria (i.e., the technology-specific layer), along with the guidelines, checkpoints and generic success criteria?

Audience

These guidelines have been written to meet the needs of many different audiences from policy makers, to managers, to those who create Web content, to those who code the pages. Every attempt has been made to make the document as readable and usable as possible while still retaining the accuracy and clarity needed in at technical guideline. For first time users, the work of the Education and Outreach working group of the Web Accessibility Initiative is highly recommended.

Scope

The guidelines cover the wide range of issues and recommendations for making we content more accessible. It includes recommendations to make pages accessible and usable by people with the full range of disabilities. In general, the guidelines do not include standard usability recommendations except where they have specific ramifications for accessibility beyond standard usability impacts.

Priorities and Techniques

Issue: provide a discussion of technology-specifics and core checkpoints.

This WCAG 2.0 Working Draft does not assign priorities to checkpoints, as did WCAG 1.0. Instead, each of the checkpoints has levels of implementation listed for it. There are 3 levels labeled "Minimum", "Level 2", and "Level 3". The Main WCAG 2.0 Draft document does not include technology specific implementation requirements or techniques, but it does include links to technology specific requirements as well as technology specific examples and techniques.

Version 2.0 of the WCAG is a follow-on and evolution of WCAG 1.0 and reflects feedback received since the publication of WCAG 1.0 in May 1999. Although the same approaches to accessibility are followed in 1.0 and 2.0, the organization and structure has been improved significantly.

The WCAG Working Group is proceeding carefully to minimize substantial differences between the WCAG 1.0 Recommendation and the WCAG 2.0 Working Draft. Refer to the Checkpoint Mapping Between WCAG 1.0 and WCAG 2.0 Working Draft for more detail on current correspondences.

Conformance

In order to claim any conformance to the guidelines it is necessary to satisfy the "MINIMUM" success criteria of every checkpoint. The minimum criteria represent those aspects of the checkpoint requirements which, in the absence of a full implementation, will nonetheless offer substantial benefit to people with disabilities by removing barriers that would otherwise make it difficult or impossible to access the content. The Level 2 and Level 3 criteria build upon this functionality, making the content accessible to people who would not be able to access it, or could do so only with substantial difficulty, if only the minimum criteria had been met.

Sites which go beyond the Minimum level of conformance can claim conformance at higher levels in several ways.

  1. If they meet all of the criterria for Level 2 or Level 3 they can claim conformance at those levels.
  2. If they meet some but not all of the criteria for Level 2 then can claim conformance at Level 1+.
  3. It is possible and recommended that sites report specifically which criteria they have met within each of the guidelines and checkpoints. This can be done using _________________________________________.

Overview of Design Principles

The overall goal is to create Web content that is Perceivable, Operable, Navigable, and Understandable by the broadest possible range of users and compatible with their wide range of assistive technologies, now and in the future.

  1. Perceivable. Ensure that all content can be presented in form(s) that can be perceived by any user - except those aspects of the content that cannot be expressed in words.
  2. Operable. Ensure that the interface elements in the content are operable by any user.
  3. Orientation/Navigation. Facilitate content orientation and navigation
  4. Comprehendible. Make it as easy as possible to understand the content and controls.
  5. Technology Robust. Use Web technologies that maximize the ability of the content to work with current and future accessibility technologies and user agents.

Accessible Web content benefits a variety of people, not just people with disabilities. In the physical world, ramps are used by bicycles, people pushing strollers, and people in wheelchairs. Similarly, accessible Web content is usable by a variety of people with and without disabilities. For example, people who are temporarily operating under constrained conditions like operating in a noisy environment or driving their car where their eyes are busy. Likewise, a search engine can find a famous quote in a movie if the movie is captioned.

Note: These principles apply only to Web content presented to a human reader. A structured database or metadata collection where the data is intended for use by another machine and thus requires no interface lies outside the scope of these guidelines.

User needs

Here are a few scenarios, by no means an exhaustive list of the variations and types of disabilities and needs:

If Web content employs the design principles described in this document, then users should be able to access the content using adaptive strategies and assistive technologies. A screen reader is an example of an assistive technology that reads the page aloud. There are many other tools people with disabilities employ to make use of Web content. For more in-depth scenarios of people with disabilities using accessible and inaccessible Web content, please read "How People with Disabilities Use the Web".

Designing Accessible Web Content

These guidelines provide the basic requirements for designing accessible Web content. This document is not designed to provide the background needed to learn about accessible web design in a through or effective manner for those interested in learning. Readers are therefor referred to the Education and Outreach group of the Web Accessibility Initiative. Further information can be found at www.w3.org/wai/.


Guideline 1 - Perceivable.
Ensure that all intended function and information can be presented in form(s) that can be perceived by any user - except those aspects that cannot be expressed in words.

Essential to any access to any Web content is the ability of the user to have the information presented in a form which they can perceive.

The checkpoints under this guideline impact individuals with sensory disabilities by allowing the information to be transformed and presented in a form which they can perceive. They also impact individuals with cognitive and language disabilities by ensuring that the information is in a format that can be perceived by mainstream and assistive technologies which can read the content to them as well as (increasingly over time) transform and present it in a form which is easier for them to understand.

Checkpoint 1.1 For all non-text content that can be expressed in words, provide a text equivalent of the function or information the the non-text content was intended to convey.

Success Criteria

You will have successfully met Checkpoint 1.1 at the Minimum Level if:
  1. Non-text content that can be expressed in words has a text-equivalent explicitly associated with it.
  2. Non-text content that can not be expressed in words has a descriptive label provided as it's text-equivalent
    • The text equivalant should fulfill the same function as the author intended for the non-text content (i.e. it presents all of the intended information and/or achieves the same function of the non-text content).
You will have successfully met Checkpoint 1.1 at Level 2 if:
  1. The site has a statement asserting that the text-equivalant has been reviewed and is believed to fulfill the same function as the author intended for the non-text content (i.e. it presents all of the intended information and/or achieves the same function of the non-text content).
You will have successfully met Checkpoint 1.1 at Level 3 if:
The following are additional ideas for enhancing a site along this particular dimension:

Definitions (informative)

A text equivalent

Note: text-equivalents should be easily convertible to braille or speech, displayed in a larger font or different colors, fed to language translator or abstracting software, etc.

Non-text content includes but is not limited to images, text in raster images, image map regions, animations (e.g., animated GIFs), applets and programmatic objects, ASCII art, scripts that present content, images used as list bullets, spacers, graphical buttons, sounds (played with or without user interaction), stand-alone audio files, audio tracks of video, and video.

Benefits (informative)

Individuals who are blind, have low vision, have cognitive disabilities or have trouble reading text for any reason can have the text read aloud to them. Individuals who are deaf, are hard of hearing or who are having trouble understanding the audio information for any reason can read the text presentation or have it translated and presented as sign language. Individuals who are blind or deaf-blind can have the information presented in braille.

Examples (informative)

Checkpoint 1.2 Provide synchronized media equivalents for time-dependent presentations.

Success criteria

You will have successfully met Checkpoint 1.2 at the Minimum Level if:
  1. an audio description is provided of all visual information in scenes, actions and events (that can't be perceived from the sound track).
    • The audio description should include all significant visual information in scenes, actions and events (that can't be perceived from the sound track) is provided to the extent possible given the constraints posed by the existing audio track (and constraints on freezing the audio/visual program to insert additional auditory description).
  2. all significant dialogue and sounds are captioned.
  3. descriptions and captions are synchronized with the events they represent.
  4. if web content is a real-time broadcast, and synchronized media equivalents are available, they are provided.
  5. if a pure audio or pure video presentation requires a user to respond interactively at specific times in the presentation, then a time-synchronized equivalant (audio, visual or text) presentation is provided.
You will have successfully met Checkpoint 1.2 at Level 2 if:
  1. The site has a statement asserting that the audio description has been reviewed and it is believed to include all significant visual information in scenes, actions and events (that can't be perceived from the sound track) is provided to the extent possible given the constraints posed by the existing audio track (and constraints on freezing the audio/visual program to insert additional auditory description).
  2. Captions and Audio descriptions are provided for all live broadcasts that are professionally produced.
You will have successfully met Checkpoint 1.2 at Level 3 if:
  1. A text "script" that includes all audio and visual information is provided.
  2. Captions and Audio descriptions are provided for all live broadcasts which provide the same information.
The following are additional ideas for enhancing a site along this particular dimension:

Definitions (informative)

A time-dependent presentation is a presentation which

Media equivalents present essential audio information visually (captions) and essential video information auditorily (audio descriptions).

Benefits (informative)

People who are deaf or have a hearing loss can access the auditory information through the captions. People who are blind or have low vision as well as those with cognitive disabilities who have difficulty interpreting visually what is happening benefit from the audio descriptions of the visual information.

People without disabilities also benefit from the media equivalents. People in noisy environments or with muted sound often use captions. Captions are used by many to develop language and reading skills. Audio descriptions also provide visual information for people who are temporarily looking away from the video presentation such as when following an instructional video and looking at their hands. Captions and text descriptions can also be used to index and search media files.

Note:Time-dependent presentations that require dual, simultaneous attention with a single sense can present significant barriers to some users. Depending on the nature of the of presentation, it may be possible to avoid scenarios where, for example, a deaf user would be required to watch an action on the screen and read the captions at the same time. However, this would not be achievable for live broadcasts (ex. a football game). Where possible, provide content so that it does not require dual, simultaneous attention or so that it gives the user the ability to effectively control/pause different media signals.

Examples (informative)

Checkpoint 1.3 [1.5] Make all content and structure available independent of presentation.

Success criteria

You will have successfully met Checkpoint 1.3 at the Minimum Level if:
  1. Any information that is conveyed through presentation formatting is also provided in either text or structure.
  2. The following can be derived programmatically (i.e. through AT compatible markup or data model) from the content without interpreting presentation.
    1. any hierarchical elements and relationships, such as headings, paragraphs and lists
    2. any non-hierarchical relationships between elements such as cross-references and linkages, associations between labels and controls, associations between cells and their headers, etc.
    3. any emphasis
You will have successfully met Checkpoint 1.3 at Level 2 if:
  1. (Presently no additional criteria for this level.)
You will have successfully met Checkpoint 1.3 at Level 3 if:
The following are additional ideas for enhancing a site along this particular dimension:

Definitions (informative)

Content is the information or meaning and function.

Presentation is the rendering of the content and structure in a form that can be sensed by the user.

Structure includes both hierarchical structure of the content and non-hierarchical relationships such as cross-references, or the correspondence between header and data cells in a table.

Benefits (informative)

Separating content and structure from presentation allows Web pages to be presented differently to meet the needs and constraints of different users without losing any of the information or structure. For example, presenting information via speech or braille (text) that was originally intended to be presented visually.

Examples (informative)

Checkpoint 1.4 Ensure that foreground content is easily differentiable from background for both auditory and visual presentations.

Success criteria

You will have successfully met Checkpoint 1.4 at the Minimum Level if:
  1. No text content is presented over a background picture, color or pattern that seriously interferes with readability unless background picture or pattern can be easily removed.
  2. Prepared audio presentations do not have background sounds which seriously interfere with foreground auditory content.
You will have successfully met Checkpoint 1.4 at Level 2 if:
  1. The site has a statement asserting that pages that might provide a problem are run through a simulator for major types of color blindness and deemed to be still easily readable.
You will have successfully met Checkpoint 1.4 at Level 3 if:
  1. There are no background pictures or patters behind foreground content
  2. Background sounds are at least 20 db lower than foreground content.
The following are additional ideas for enhancing a site along this particular dimension:

Definitions (informative)

sufficient contrast?

Benefits (informative)

Examples (informative)


Guideline 2 - Operable.
Ensure that the interface elements in the content are operable by any user.

Also essential to accessibility is the ability to be able to operate all of the interface elements on the page without requiring the use of specific input devices.

This guideline impacts individuals who are blind or have low vision and have trouble with eye-hand coordination input device, individuals with physical disabilities who cannot handle direct pointing devices accurately, and individuals with language and learning disabilities who would like to use speech input now or in the future.

Checkpoint 2.1 [2.5] Provide keyboard access to all functionality of the content.

Success criteria

You will have successfully met Checkpoint 2.1 at the Minimum Level if:
  1. all functions of the content can be operated from a standard keyboard without requiring simultaneous activation of multiple character keys.
You will have successfully met Checkpoint 2.1 at Level 2 if:
  1. Activation does not require any keys adding only alphanumeric plus tab, enter, backspace, escape, shift, control and alt.
You will have successfully met Checkpoint 2.1 at Level 3 if:
The following are additional ideas for enhancing a site along this particular dimension:

Benefits (informative)

Individuals who are blind (and cannot use pointing devices) can have access to the functionality of the product.

Individuals with severe physical disabilities can use speech input (which simulates keystrokes) to both enter data and operate the interface elements on the page.

Examples (informative)

Example 1: a submit button. A submit button can be activated by tabbing to it with the keyboard and pressing the enter key and by using a keyboard shortcut (in addition to the ability to directly "press" the button).

Checkpoint 2.2 [2.4] Allow users to control any time limits on their reading, interaction or responses unless control is not possible due to the nature of real-time events or competition.

Success criteria

You will have successfully met Checkpoint 2.2 at the Minimum Level if:
  1. At least one of the following is true for each time limit:
    1. the user is allowed to deactivate the time limits,
    2. or the user is allowed to adjust the time limit over a wide range which is at least 10 times the average user's preference,
    3. or the user is warned before time expires and given at least 10 seconds to extend the time limit
    4. or the time limit is due to a real-time event (e.g. auction) and no alternative to the time limit is possible
    5. or the time limit is part of a competitive activity where timing is an essential part of the activity (e.g. competitive gaming, time based testing).
You will have successfully met Checkpoint 2.2 at Level 2 if:
  1. (Presently no additional criteria for this level.)
You will have successfully met Checkpoint 2.2 at Level 3 if:
The following are additional ideas for enhancing a site along this particular dimension:

Definitions (informative)

Real-time events are those that are based on the occurrence of events in real-time where the events are not under the control of the author.

A competitive activity is an activity where timing is an essential part of the design of the activity. Removal of the time element would change the performance of the participants. Activities that have no time basis or time limits might be preferred and may be required for some venues but this would require a complete redesign of the activity or test and would therefore fall under guidelines

Benefits (informative)

People with reading disabilities, cognitive disabilities, and learning disabilities often need longer than most people to read and comprehend written text. People with physical disabilities might not be able to move quickly or accurately enough to interact with moving objects.

Content that is updated often might not be processed and read in time or in the proper order by an assistive technology or voice browser.

Examples (informative)

Examples of content that requires a response within a timed interval:

more examples?

Checkpoint 2.3 [2.6] Avoid causing the screen to flicker.

Success criteria

You will have successfully met Checkpoint 2.3 at the Minimum Level if:
  1. At least one of the following is true:
    1. animation or other content does not visibly or purposely flicker between 3 and 49 Hz.
    2. if flicker is unavoidable, the user is warned of the flicker before they go to the page, and as close a version of the content as is possible without flicker is provided.
You will have successfully met Checkpoint 2.3 at Level 2 if:
  1. The site has a statement asserting that animation or other content does not visibly or purposely flicker between 3 and 49 Hz.
  2. The site has a statement asserting that pages that might provide a problem has been tested [using XYZ tool], only pages with unavoidable flicker remain and appropriate warnings along with a close alternative presentation has been provided for these pages.
You will have successfully met Checkpoint 2.3 at Level 3 if:
The following are additional ideas for enhancing a site along this particular dimension:

NOTE: Trace is exploring an automated flicker testing tool.

Benefits (informative)

People with photosensitive epilepsy can have seizures triggered by flickering or flashing in the 3 to 49 flashes per second (Hertz) range with a peak sensitivity at 20 flashes per second.

People with distractibility problems may not be able to focus on page content with flicker occurring in same visual field.


Key to effective use of Web content is the ability to obtain and keep one's orientation within a document and/or website, and the ability to efficiently move about in the site or document.

Checkpoint 3.1 [1.3A] Provide structure within content.

Success criteria

You will have successfully met Checkpoint 3.1at the Minimum Level if:
  1. The following minimum structure elements are present.
    1. titles on major sections of long documents
    2. paragraphs
You will have successfully met Checkpoint 3.1 at Level 2 if:
  1. The site has a statement asserting that author(s) or others have reviewed content and added as much structure as they felt was appropriate or possible.
You will have successfully met Checkpoint 3.1 at Level 3 if:
  1. Information is provided that would allow AT to determine at least one logical, linear reading order
  2. diagrams are constructed in a fashion so that they have structure that can be accessed by the user.
The following are additional ideas for enhancing a site along this particular dimension

NOTE:Because the form and origin of content (including letters, poetry, historical documents, etc.) varies so greatly, specific criteria for the type and amount of structure to be put into content can not be standardized. Objective success criteria cannot therefore be formulated that would apply across media and documents. Advisory recommendations are, however, listed below to provide guidance in adding key structural elements into the content. See also the techniques documents for the different technologies.

  1. Break up text into logical paragraphs.
  2. Provide hierarchical sections and titles, particularly for longer documents
  3. Reveal important non-hierarchical relationships, such as cross-references, or the correspondence between header and data cells in a table, so that they are represented unambiguously in the markup or data model.
  4. Divide very large works into sections and or chapters with logical labels.
  5. others?

Definitions (informative)

The structure of content represents changes in context. For example,

  1. A book is divided into chapters, paragraphs, lists, etc. Chapter titles help the reader anticipate the meaning of the following paragraphs. Lists clearly indicate separate, yet related ideas. All of these divisions help the reader anticipate changes in context.
  2. A bicycle is divided into wheels and a frame. Further, a wheel is divided into a tire and a rim. In an image of the bicycle, one group of circles and lines becomes "wheel" while another group becomes "frame."

Benefits (informative)

When the logical structure is provided in markup or a data model,

Examples (informative)

Checkpoint 3.2 [3.2] Emphasize structure through presentation(s), positioning, and labels.

Success criteria

You will have successfully met Checkpoint 3.2 at the Minimum Level if:
  1. The structural elements present have a different visual appearance or auditory characteristic than the other structural elements.
You will have successfully met Checkpoint 3.2 at Level 2 if:
  1. (?? should we have something in level 2 about providing more than one type of structural emphasis to match different display technologies)
  2. (Presently no additional criteria for this level.)
You will have successfully met Checkpoint 3.2 at Level 3 if:
The following are additional ideas for enhancing a site along this particular dimension:

NOTE:Because the form and origin (including letters, art, historical documents, etc) of content varies so greatly, specific criteria for the type and amount of emphasis to be provided can not be standardized. Objective success criteria cannot therefore be formulated that would apply across media and documents. Advisory recommendations are however listed below to provide guidance in emphasizing the structure of content. See also the techniques documents for the different technologies.

  1. For visual presentations, use font variations, styles, size and white space to emphasize structure.
  2. Use color and graphics to emphasize structure.
  3. For auditory presentations, use different voice characteristics and/sounds for major headings, sections and other structural elements.
  4. If content is targeted for a specific user group and the presentation of the structured content is not salient enough to meet the needs of your audience, use additional graphics, colors, sounds, and other aspects of presentation to emphasize the structure.
  5. Provide a table of contents or navigation map of the document

NOTE: Ensure that the structural and semantic distinctions are provided in the markup. Refer to checkpoint 2.2.

Benefits (informative)

Presentation that emphasizes structure:

Examples (informative)

Success criteria

You will have successfully met Checkpoint 3.3 at the Minimum Level if:
  1. Sites that have more than two layers have at least one other method for exploration besides using the links on the home page. (A home page and one layer of pages linked off of it would be two layers)
  2. A link to the alternate exploration method(s) must be provided on the home page.
You will have successfully met Checkpoint 3.3 at Level 2 if:
  1. Sites that have documents that span multiple files provide the documents as a single file or provide a search function which would allow the user to search for a word across only the files that make up that document.
You will have successfully met Checkpoint 3.3 at Level 3 if:
The following are additional ideas for enhancing a site along this particular dimension:

Definitions (informative)

Asite navigation mechanismis a mechanism for easily orienting and moving about within the site. Site navigation mechanisms include but are not limited to:

Benefits (informative)

Providing different navigation mechanisms can provide a better match between different peoples skill, background knowledge, visual vs. text orientation, and the type of information they are seeking at the moment.

People with cognitive disabilities may find it easier to ask for what they want than to deduce its location from categorical choices.

People with low vision or blindness may find search techniques that fetch everything that relates to a topic of interest to be easier than techniques that require them to scan lists or pages for the items.

Checkpoint 3.4 [3.1] Use Consistent But Not Necessarily Identical Presentation

Success criteria

You will have successfully met Checkpoint 3.4 at the Minimum Level if:
  1. The location of key orientation and navigational elements are generally found in one or two locations or their locations are otherwise predictable.
You will have successfully met Checkpoint 3.4 at Level 2 if:
  1. The site has a stateent asserting that they have reviewed the content and found that the location of key orientation and navigational elements and are generally found in one or two locations or their locations are otherwise predictable.
You will have successfully met Checkpoint 3.4 at Level 3 if:
The following are additional ideas for enhancing a site along this particular dimension:
  1. Place navigation bars in a consistent location whenever possible
  2. Similar layout for user interface components is used for sections or whole site,
  3. Similar user interface components are labeled with similar terminology,
  4. Consistent use of headers
  5. Use templates for consistent presentation for sections or whole site
  6. Pages with similar function have similar appearance and layout

Definitions (informative)

Presentation includes, but is not limited to:

Benefits (informative)

Consistency helps users predict where to find information on each page of your site. It also helps users determine the relationships between items in the content. This understanding of the structure helps users navigate, orient themselves.

However, differences in presentation help users determine that they have succeeded in loading a new page. Pages that are clearly different also makes it easier for users to tell where they are and to remember where information is located.

Checkpoint 3.5 [2.2 and 2.3] Provide consistent and predictable responses to user actions.

Success criteria

You will have successfully met Checkpoint 3.5 at the Minimum Level if:
  1. Where inconsistent or unpredictable responses are essential to the function of the content (e.g. mystery games, adventure games, tests, etc.) the user is warned in advance of encountering them.
  2. Wherever there are extreme changes in context, one of the following is true:
    1. an easy to find setting, that persists for the site visit, is provided for the user to deactivate processes or features that cause extreme changes in context or
    2. extreme changes in context are identified before they occur so the user can determine if they wish to proceed or so they can be prepared for the change
You will have successfully met Checkpoint 3.5 at Level 2 if:
  1. The site has a statement asserting that authors or others have reviewed the content and found that where inconsistent or unpredictable responses are essential to the function of the content (e.g. mystery games, adventure games, tests, etc.) the user is warned in advance of encountering them.
You will have successfully met Checkpoint 3.5 at Level 3 if:
The following are additional ideas for enhancing a site along this particular dimension:
  1. controls that look or sound the same are designed to act the same,
  2. conventions likely to be familiar to the user have been followed,
  3. unusual user interface features or behaviors that are likely to confuse the first-time user are described to the user before they are encountered.

Definitions (informative)

Mechanisms that cause extreme changes in context include:

Benefits (informative)

If the user is unable to detect extreme changes because the cues are not obvious, then they may not realize the context has changed. People who are blind will not see obvious visual cues such as a new window popping up and may not know why the back button no longer works. Some people with low vision, some people with dyslexia and other people who have difficulty interpreting visual cues may need additional cues to detect extreme changes in context.

Providing responses to user actions is important feedback for the user. This lets them know that your site is working properly and encourages them to keep interacting. When the user receives an unexpected response, they might think something is wrong or broken. Some people might get so confused they will not be able to use your site. Common responses to user actions:

These actions should be predictable and sensible to the end user. Make interactions consistent, both throughout the site and with commonly used interaction metaphors used throughout the Web.

Examples (informative)

Checkpoint 3.6 [2.7A] Provide methods to minimize error and provide graceful recovery.

Success criteria

You will have successfully met Checkpoint 3.6 at the Minimum Level if:
  1. If an error is detected, feedback is provided to the user identifying the error.
You will have successfully met Checkpoint 3.6 at Level 2 if:
  1. The site has a statement asserting that the content has been reviewed and is believed to have incorporated error prevention and recovery methods they felt were possible and appropriate.
You will have successfully met Checkpoint 3.6 at Level 3 if:
  1. where possible, the user is allowed to select from a list of options as well as directly generate the text.
  2. errors are identified specifically and suggestions for correction are provided where possible
  3. checks for misspelled words are applied and correct spellings are suggested when text entry is required,
  4. where consequences are significant and time-response is not important, one of the following is true
    1. actions are reversible where possible
    2. where not reversible, action is checked for errors in advance.
    3. where not reversible, and not checkable, a confirmation is asked before acceptance
The following are additional ideas for enhancing a site along this particular dimension:

Benefits (informative)

People with writing disabilities and people with dyslexia often have difficulty writing text in forms or other places that need text input. People with speech disabilities might not be recognized properly in voice input applications.

Examples (informative)


Guideline 4 - Comprehension.
Make it as easy as possible to understand the content and controls.

To help people understand the information you are presenting, consider the various ways that people learn. Keep in mind the variety of backgrounds and experiences people will bring to your site. Using language, illustrations, and concepts that they are likely to know, highlighting the differences and similarities between concepts, and providing explanations for unusual terms can all facilitate understanding.

Checkpoint 4.1 [3.3] Write as clearly and simply as is appropriate for the content.

Success criteria

You will have successfully met Checkpoint 4.1 at the Minimum Level if:
  1. Content under site control is written as clearly and simply as author feels appropriate for the content.
You will have successfully met Checkpoint 4.1 at Level 2 if:
  1. A statement is provided on the site that states that those responsible for the site have reviewed the materials on the site and the content under their control is written as clearly and simply as they feel is appropriate.
You will have successfully met Checkpoint 4.1 at Level 3 if:
The following are additional ideas for enhancing a site along this particular dimension:

NOTE: It is very difficult to determine what makes writing clear and simple for all topics. Some content is derived from other sources and is copyrighted so it cannot be altered. Some materials or topics cannot be communicated accurately in simple language. Also, since some people cannot understand the content no matter how simply it is written, it is not possible to make any content accessible to everyone. Specific objective criteria that could be applied across all types of content are therefore not possible. Advisory recommendations are however listed below to provide guidance in this area. See also the techniques documents for the different technologies.

  1. Provide an outline or a summary for your document.
  2. Break up long paragraphs into shorter ones, with one idea per paragraph.
  3. Break up long sentences into shorter ones.
  4. Provide accurate unique page titles.
  5. Ensure that headings and link text are unique and that they make sense when read out of context.
  6. Provide definitions for any jargon or specialized terminology used in your document.
  7. Provide explanations of figurative, metaphorical, or idiomatic uses of language (for example, 'haven't seen you in a coons age' or 'the sight tore my heart out')."
  8. Language is used that your intended audience ought to be familiar with,
  9. When introducing new concepts or terms, they are defined or annotated in language that the audience should be familiar with or definitions or explanations are linked to that might be easier to understand.

Benefits (informative)

Authors should strive for clear and simple writing to aid all users, especially those with cognitive, learning, and/or reading disabilities. This should not discourage you from expressing complex or technical ideas. Using clear and simple language also benefits people whose first language differs from your own, including those people who communicate primarily in sign language.

Checkpoint 4.2 [3.4] Supplement text with non-text content.

Success criteria

You will have successfully met Checkpoint 4.2 at the Minimum Level if:
  1. Authors have included non-text content to supplement text for key pages or sections of the site where they felt it was appropriate.
You will have successfully met Checkpoint 4.2 at Level 2 if:
  1. There is a statement on the site asserting that the materials have been reviewed and that text has been supplemented with non-text content to the extent deemed appropriate by the author.
You will have successfully met Checkpoint 4.2 at Level 3 if:
  1. There is a statement on the site asserting that non-text content has been added to the site for key pages or sections specifically to make the site more understandable by users who cannot understand the text only version of the site.
The following are additional ideas for enhancing a site along this particular dimension:

NOTE: Supplementing text with non-text (e.g. graphics, sound, smell, etc) is useful for all users. However there are no clear guidelines as it relates to disability. Specific objective criteria that could be applied across all types of content are therefore not possible.Advisory recommendations are, however, listed below to provide guidance in this area. See also the techniques documents for the different technologies.

  1. (do we have any items to go here or do we just have examples for below?)

Definitions (informative)

Non-text content - includes images, text in raster images, image map regions, animations (e.g., animated GIFs), applets and programmatic objects, ASCII art, scripts, images used as list bullets, spacers, graphical buttons, sounds (played with or without user interaction), stand-alone audio files, audio tracks of video, and video.

Is this definition adequate?

Benefits (informative)

Sounds, graphics, videos and animations can help make concepts presented in a Web site easier to understand, especially for people with cognitive, reading, or learning disabilities or those who are unfamiliar with the language of the text of the site.

Note: "Designers need to be cautious in deciding when to use illustrations. Reading a picture is probably a learned activity that is easier for some than others. Some users skip the pictures; others read only the pictures. Designers must also recognize that visual conventions are not universal and that individuals develop their own mental schema and expectations in interpreting visual information.

Examples (informative)

Checkpoint 4.3 [3.5] Annotate complex, abbreviated, or unfamiliar information with summaries and definitions.

[ Alternate Checkpoint Approach: Provide full information necessary to allow unambiguous interpretation of text including abbreviations. ]

Success criteria

You will have successfully met Checkpoint 4.3 at the Minimum Level if:
  1. Acronyms and Abbreviations are defined the first time they appear in text.
You will have successfully met Checkpoint 4.3 at Level 2 if:
  1. There is a statement on the site that states that authors or site owners have reviewed the content provided annotations for information where they feel is appropriate
You will have successfully met Checkpoint 4.3 at Level 3 if:
The following are additional ideas for enhancing a site along this particular dimension:
  1. Provide a definition or link (with the first occurrence) of phrases, words, acronyms, and abbreviations specific to a particular community.
  2. Provide a summary for relationships that may not be obvious from analyzing the structure of the table but that may be apparent in a visual rendering of the table.
  3. If contracted forms of words are used such that they are ambiguous, provide semantic markup to make words unique and interpretable.

Definitions (informative)

Content is considered complex if the relationships between pieces of information are not easy to figure out. If the presentation of the information is intended to highlight trends or relationships between concepts, these should be explicitly stated in the summary.

Examples of complex information:

Content might be unfamiliar if you are using terms specific to a particular community. For example, many of the terms used in this document are specific to the disability community.

Benefits (informative)

Summarizing information that is difficult to understand helps people who do not read well. Providing a summary of the visual cues that show relationships between complex information helps people who do not use visual cues or who have difficulty using visual cues. For example, people who are blind do not use any visual cues, while people with dyslexia or people with low vision might have difficulty interpreting visual cues.

Defining key terms and specialized language will help people who are not familiar with the topic. Providing the expansion of abbreviations and acronyms not only helps people who are not familiar with the abbreviation or acronym but can clarify which meaning of an abbreviation or acronym is appropriate to use. For example, the acronym "ADA" stands for both the American with Disabilities Act as well as the American Dental Association.

Checkpoint 4.4 [1.4] Identify the primary natural language of text and text equivalents and all changes in natural language.

ISSUE: How do you mark the language shifts inside text equivalents?

Success criteria

You will have successfully met Checkpoint 4.4 at the Minimum Level if:
  1. passages or fragments of text occurring in the content which are written in a language other than the primary language of the content as a whole, are identified, including specification of the language of the passage or fragment.
You will have successfully met Checkpoint 4.4 at Level 2 if:
  1. (Presently no additional criteria for this level.)
You will have successfully met Checkpoint 4.4 at Level 3 if:
The following are additional ideas for enhancing a site along this particular dimension:

You will have successfully identified the primary natural language of text and text equivalents and all changes in natural language if:

  1. changes in language are identified at the level the changes occur.
    Note: If there is never a change throughout a whole site, then identification can occur at the highest level (usually at a page or document level). If changes occur at the word or phrase level, then changes should be identified at the word or phrase level using the markup appropriate to the markup language in use.

Definitions (informative)

Natural languages are those used by humans to communicate, including spoken, written, and signed languages.

Benefits (informative)

Oftentimes, phrases from various languages are interspersed in writing. When these phrases are identified, a speech synthesizer can voice text with the appropriate accent and pronunciation. When they are not identified, the speech synthesizer will use the default accent and pronunciation dictionary which can make the phrase intelligible. Identifying changes in language will also allow a tool to ask for automatic translations of that content. When editing content, authoring tools can switch between appropriate spelling dictionaries.

Examples (informative)


Guideline 5 - Technology Robustness. Use Web technologies that maximize the ability of the content to work with current and future accessibility technologies and user agents.

Checkpoint 5.1 [4.2] Use technologies according to specification.

Success criteria

You will have successfully met Checkpoint 5.1 at the Minimum Level if:
  1. except where the site has documented that a specification was violated for backward compatibility, the markup has passed validity tests of the language (whether it be conforming to a schema, DTD, or other tests described in the specification), structural elements and attributes are used as defined in the specification, accessibility features are used, and deprecated features are avoided.
  2. for API's: programming standards for the language are followed.
  3. accessibility features and API's are used when available.
You will have successfully met Checkpoint 5.1 at Level 2 if:
  1. for markup: the markup has passed validity tests of the language (whether it be conforming to a schema, DTD, or other tests described in the specification), structural elements and attributes are used as defined in the specification, accessibility features are used, and deprecated features are avoided.
You will have successfully met Checkpoint 5.1 at Level 3 if:
The following are additional ideas for enhancing a site along this particular dimension:

Are protocols relevant to this checkpoint? If so, why, and should we require that they be used according to specification? Obviously there are interoperability advantages in doing so, but is this pertinent to accessibility?

Benefits (informative)

When languages, API's, and protocols are used according to specification, tools that use the results will be able to do so as intended and expected.

Examples (informative)

Checkpoint 5.2 [4.4] Ensure that content remains usable when technologies that modify default user agent processing or behavior are turned off or not supported.

Issue: define "default" for purposes of this checkpoint. If "default" were taken to mean "a user agent's default rendering", then this would defeat the purpose of the checkpoint, because (for many user agents) the default is to apply style sheets, invoke scripts and programmatic objects, etc.

Success criteria

You will have successfully met Checkpoint 5.2 at the Minimum Level if:
  1. (Presently no additional criteria for this level.)
You will have successfully met Checkpoint 5.2 at Level 2 if:
  1. (Presently no additional criteria for this level.)
You will have successfully met Checkpoint 5.2 at Level 3 if:
The following are additional ideas for enhancing a site along this particular dimension:

original success criteria

Checkpoint 5.2 Design for backward compatibility <notes>

Again, this is what we say when we explain the checkpoint, so let's just say it</notes>

Success criteria:

Your site can be considered backward compatible if

- You have determined and documented your baseline browser requirements in metadata and/or a policy statement on your site.

- Your content is still usable when features above your baseline (for example, scripting and stylesheets) are turned off

Informative:

1) When determining your baseline browser requirements, consider that assistive hardware and software is often slow to adapt to technological advances, and the availability of assistive technology varies across natural languages. Verify that assistive technology compatible with the technologies you choose is available in the natural language(s) of your content.

<notes>

The concept of a baseline browser is made explicit.

The definition of that baseline is left up to the author. This will probably be controversial.

Here's the reasoning:

a) The working group has yet to come up with a workable solution for defining a baseline and having it not become obsolete. I'm not convinced that it is possible to do so.

b) The author has much better information than we do about the specific situation in which his content will be used.

This includes things like audience, available tech in a given language, and the state of technology at the time he's reading the guidelines (not the time we're writing them). We could perhaps provide a few sample baselines, like the no script/no stylesheets standard assumed by WCAG 1.0. Again, added the concept of technology available in the language of the content.

</notes>

2) In some situations, there are trade-offs between this checkpoint and checkpoints 4.1 and 4.2.

Older user agents may not be compliant to standards.

Newer technologies (or their accessibility features) may break older user agents. In these situations, you will need to make a judgment call as to which is more important for your audience, and adjust your baseline browser requirements accordingly.

<notes>

We will never get around this trade-off, so let's acknowledge it, and see what we can come up with to help the author make the right decision.

</notes>

Benefits (informative)

In determining the extent to which older technologies should be supported, keep in mind that

Examples (informative)

Checkpoint 5.3 [4.1A] Choose technologies that support interoperability and compatibility.

Success criteria

You will have successfully met Checkpoint 5.3 at the Minimum Level if:
  1. (Presently no additional criteria for this level.)
You will have successfully met Checkpoint 5.3 at Level 2 if:
  1. (Presently no additional criteria for this level.)
You will have successfully met Checkpoint 5.3 at Level 3 if:
The following are additional ideas for enhancing a site along this particular dimension:

original success criteria

  1. permits equivalents to be associated with or synchronized with auditory, graphical, and multimedia content,
  2. allows the logical structure of the content to be defined independent of presentation,
  3. supports device-independence,
  4. is documented in published specifications and can be implemented by user agent and assistive technology developers,
  5. is supported by user agents and assistive technologies.

Issue: are these success criteria complete? If not, what should be added or changed? Should we provide a link to the XML guidelines?

Issue: should the checkpoint be reworked (or an additional checkpoint inserted here) to require that content be designed, as far as possible, so that it is amenable to automated accessibility testing?

Checkpoint 5.3 Choose technologies that are designed to support accessibility

<notes> This is what we say when we're explaining the checkpoint. Let's make it the checkpoint, so we don't have to explain it.</notes>

Success Criteria:

<notes> The big change here is that I'm putting a lot more weight on implemented technologies, and their interactions with other software in the real world. I've also added the concept of looking at available technologies based on the human/natural language of the content. The idea is that if I'm creating a French site, then it matters a lot more that it works with French screen readers than with Swedish ones. I'm not sure this is the right place for this, but it's another example of adding implementation and real-world concerns to the success criteria. </notes>

Benefits (informative)

Markup languages, multimedia formats, software interface standards, etc., vary in their support of accessibility. When choosing which technologies to use, consider how easy it is to apply these guidelines.

Checkpoint 5.4 [4.3A] Ensure that user interfaces are accessible or provide an accessible alternative.

Success criteria

You will have successfully met Checkpoint 5.4 at the Minimum Level if:
  1. (Presently no additional criteria for this level.)
You will have successfully met Checkpoint 5.4 at Level 2 if:
  1. (Presently no additional criteria for this level.)
You will have successfully met Checkpoint 5.4 at Level 3 if:
The following are additional ideas for enhancing a site along this particular dimension:

original success criteria

  1. accessibility conventions of the markup or programming language (API's or specific markup) are used,
  2. any applications with custom interfaces conform to at least Level A of UAAG 1.0. If the application cannot be made accessible, an alternative accessible solution is provided,
  3. device-independent access to functionality is provided,
  4. the interface has been tested using a variety of assistive technologies and preferably real people with disabilities who use assistive technologies to determine that assistive technologies can access all information on the page or hidden within the page.

Issue: it would be possible to comply with the checkpoint without carrying out tests (either with users or with assistive technologies). Conversely, it is possible to conduct tests, but still fail to meet the checkpoint (with respect to assistive technologies that were not tested, for example). Should this success criterion be deleted?

FROM CYNTHIA SHELLY -- COMMENTS ON LAST ITEMS THESE WERE NOT INCORPORATED INTO THE DOC ABOVE BECAUSE WE MISSED THEM

POSTED HERE FOR DISCUSSION

I took a stab at re-writing several of the checkpoints under guideline

4. This is really rough, but you'll get the idea. The stuff between the<notes></notes> tags are explanations that would not be in the draft.

Checkpoint 4.2 [5.1 ABOVE] Use technologies according to specification

Success criteria

* passing the validity tests of the language would include conforming to a schema, DTD, or other tests described in the specification.

<notes>changes here are editorial. Made "use the accessibility features" explicit, and moved the parenthetical phase to a footnote.

</notes>

Benefits (informative)

Asking someone to access your Web site without their assistive technology is like asking someone to access a building without their wheelchair. Assistive technologies are an essential part of the lives of many people with disabilities.