Table of contents:

1. Introduction
2. Themes of Accessible Design
   1. Ensuring Graceful Transformation
   2. Making Content Understandable and Navigable
   3. How the Guidelines are Organized
3. Priorities
4. Conformance
5. Web Content Accessibility Guidelines
   1. Provide equivalent alternatives to auditory and visual content
   2. Don’t rely on color alone
   3. Use markup and style sheets and do so properly
   4. Clarify natural language usage
   5. Create tables that transform gracefully
   6. Ensure that pages featuring new technologies transform gracefully
   7. Ensure user control of time-sensitive content changes
   8. Ensure direct accessibility of embedded user interfaces.
   9. Design for device-independence
   10. Use interim solutions
   11. Use W3C technologies and guidelines
   12. Provide context and orientation information
   13. Provide clear navigation mechanisms
   14. Ensure that documents are clear and simple

1. Introduction

This document is an overview of the Web Accessibility Guidelines 1.0 published by the W3C (World Wide Web Consortium) on the 5th of May 1999. Most of the text has been simply copy-pasted from the original document and a few minor notes were added. This document aims to provide an introduction to accessibility issues for authors of small or medium size websites (e.g. with a relatively low level of multimedia elements).

For those unfamiliar with accessibility issues related to Web page design, consider that many users may be visiting your Web site from contexts very different to your own:

 They may not be able to see, hear, move, or may not be able to process some types of information easily or at all.
 They may not have or be able to use a keyboard or mouse.
 They may have a text-only screen, a small screen, or a slow Internet connection.
 They may have an early version of a browser, a different browser entirely, a voice browser, or a different operating system.
 They may not speak or understand fluently the language in which the document is written.

2. Themes of Accessible Design

Creating an accessible design is seperated into two themes: ensuring graceful transformation, and making content understandable and navigable.

2.1 Ensuring Graceful Transformation

Pages that transform gracefully remain accessible despite any of the constraints described in the introduction.

 Separate structure from presentation For example, seperate the html design from the content of the website.
 Provide text equivalents to images.
 Create documents that work even if the user cannot see and/or hear. Users who are blind can use special software for speech synthesis or braille displays.

The theme of graceful transformation is addressed primarily by guidelines 1 to 11.

2.2 Making Content Understandable and Navigable

This includes not only making the language clear and simple, but also providing understandable mechanisms for navigating within and between pages.

Not all users can make use of visual clues such as proportional scroll bars, or graphics that guide sighted users of graphical desktop browsers. Users also lose contextual information when they can only view a portion of a page, either because they are accessing the page one word at a time (speech synthesis or braille display), or one section at a time (small display, or a magnified display). Without orientation information, users may not be able to understand very large tables, lists, menus, etc.

The theme of making content understandable and navigable is addressed primarily in guidelines 12 to 14.

3. How the Guidelines are Organized

This document has a similar structure as the original document for this overview. Each guideline listed below include a brief overview of the guideline and a list of checkpoints to satisfy the basic priority (Priority 1 for Level "A").

This overview only presents the guidelines that apply to the average site, therefore excluding multimedia elements (movies, special applets, etc.), frames (which are not recommended anyway) and programmable objects. If your site includes such elements, please refer to the full document.

4. Priorities

Each checkpoint has a priority level based on the checkpoint’s impact on accessibility.

[Priority 1]

Websites must satisfy this checkpoint. Otherwise, one or more groups will find it impossible to access information in the document.

[Priority 2]

Websites should satisfy this checkpoint. Otherwise, one or more groups will find it difficult to access information in the document.

[Priority 3]

Websites may address this checkpoint. Otherwise, one or more groups will find it somewhat difficult to access information in the document. Satisfying this checkpoint will improve access to Web documents.

5. Conformance

 Conformance Level "A": all Priority 1 checkpoints are satisfied;
 Conformance Level "Double-A": all Priority 1 and 2 checkpoints are satisfied;
 Conformance Level "Triple-A": all Priority 1, 2, and 3 checkpoints are satisfied;

Note. Conformance levels are spelled out in text so they may be understood when rendered to speech.

For claims of conformance, refer to the full document by the W3C.

6. Web Content Accessibility Guidelines

 Guideline 1. Provide equivalent alternatives to auditory and visual content.

Provide content that, when presented to the user, conveys essentially thesame function or purpose as auditory or visual content.

Although some people cannot use images, movies, sounds, etc. directly, they may still use pages that include equivalent information to the visual or auditory content. The equivalent information must serve the same purpose as the visual or auditory content. Thus, a text equivalent for an image of an upward arrow that links to a table of contents could be "Go to table of contents". In some cases, an equivalent should also describe the appearance of visual content (e.g., for complex charts or diagrams) or the sound of auditory content (e.g., for audio samples used in education).

Checkpoints:

1.1 Provide a text equivalent for every non-text element (e.g., via "alt", "longdesc", or in element content). This includes: images, graphical representations of text (including symbols) and ascii art (such as smileys).

 Guideline 2. Don’t rely on color alone.

Ensure that text and graphics are understandable when viewed without color. people who cannot differentiate between certain colors and users with devices that have non-color or non-visual displays will not receive the information.

Checkpoints:

2.1 Ensure that all information conveyed with color is also available without color, for example from context or markup.

 Guideline 3. Use markup and style sheets and do so properly.

Mark up documents with the proper structural elements. Use style sheets. Misusing markup for a presentation effect (e.g., using a table for layout or a header to change the font size) makes it difficult for users with specialized software to understand the organization of the page or to navigate through it.

Checkpoints:

3.5 Priority 2. Use header elements to convey document structure and use them according to specification. For example, in HTML, use H2 to indicate a subsection of H1. Do not use headers for font effects.

 Guideline 4. Clarify natural language usage

Use markup that facilitates pronunciation or interpretation of abbreviated or foreign text. When abbreviations and natural language changes are not identified, they may be indecipherable when machine-spoken or brailled.

Checkpoints:

4.1 Clearly identify changes in the natural language of a document’s text and any text equivalents (e.g., captions). For example, in HTML use the "lang" attribute.

4.2 Priority 3. Specify the expansion of each abbreviation or acronym in a document where it first occurs. For example, in HTML, use the "title" attribute of the ABBR and ACRONYM elements.

 Guideline 5. Create tables that transform gracefully.

Ensure that tables have necessary markup to be transformed by accessible browsers and other user agents.

Checkpoints:

5.1 For data tables, identify row and column headers. For example, in HTML, use TD to identify data cells and TH to identify headers.

 Guideline 6. Ensure that pages featuring new technologies transform gracefully.

Ensure that pages are accessible even when newer technologies are not supported or are turned off.

Checkpoints:

6.1 Organize documents so they may be read without style sheets.

6.2 Ensure that equivalents for dynamic content are updated when the dynamic content changes.

6.3 Ensure that pages are usable when scripts or other programmatic objects are turned off (for example, Flash and JavaScript). If this is not possible, provide equivalent information on an alternative accessible page.

 Guideline 7. Ensure user control of time-sensitive content changes.

Ensure that moving, blinking, scrolling, or auto-updating objects or pages may be paused or stopped.

Checkpoints:

7.1 Avoid causing the screen to flicker. For example, do not use the BLINK or MARQUEE elements (which are not defined in any W3C HTML specification anyway).

 Guideline 8. Ensure direct accessibility of embedded user interfaces.

This guideline does not apply to the scope of this overview.

 Guideline 9. Design for device-independence.

Use features that enable activation of page elements via a variety of input devices. This guideline does not apply to the scope of this overview.

 Guideline 10. Use interim solutions.

Use interim accessibility solutions so that assistive technologies and older browsers will operate correctly. For example, older browsers do not allow users to navigate to empty edit boxes. Older screen readers read lists of consecutive links as one link. Also, popping up new windows can be very disorienting to users who cannot see that this has happened.

Checkpoints:

10.1 Priority 2. Do not cause pop-ups or other windows to appear and do not change the current window without informing the user.

 Guideline 11. Use W3C technologies and guidelines.

Use W3C technologies (according to specification) and follow accessibility guidelines. Where it is not possible, provide an alternative version of the content. For example: provide alternatives to PDF documents, Flash animations, MS Word or Open Office documents, etc.

Checkpoints:

11.4 If you cannot create an accessible page, provide a link to an alternative page that uses W3C technologies, is accessible, has equivalent information (or functionality), and is updated as often as the inaccessible (original) page.

 Guideline 12. Provide context and orientation information.

Provide context and orientation information to help users understand complex pages or elements.

Checkpoints:

12.1 Title each frame to facilitate frame identification and navigation. For example, in HTML use the "title" attribute on FRAME elements.

 Guideline 13. Provide clear navigation mechanisms.

Provide clear and consistent navigation mechanisms — orientation information, navigation menus, a site map, etc. — to increase the likelihood that a person will find what they are looking for at a site.

Checkpoints:

13.1 Priority 2. Clearly identify the target of each link. For example, do not use "here" or "this page" as the name for a link.

 Guideline 14. Ensure that documents are clear and simple.

Ensure that documents are clear and simple so they may be more easily understood. Consistent page layout, recognizable graphics, and easy to understand language benefit all users. Using clear and simple language promotes effective communication.

Checkpoints:

14.1 Use the clearest and simplest language appropriate for a site’s content.