W3C Web Accessibility Initiative (WAI) Guidelines

1. Provide equivalent alternatives to auditory and visual content.
Provide content that, when presented to the user, conveys essentially the same function or purpose as auditory or visual content.

2. Don't rely on color alone.
Ensure that text and graphics are understandable when viewed without color.

3. Use markup and style sheets and do so properly.
Mark up documents with the proper structural elements. Control presentation with style sheets rather than with presentation elements and attributes.

4. Clarify natural language usage.
Use markup that facilitates pronunciation or interpretation of abbreviated or foreign text.

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

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.

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.

8. Ensure direct accessibility of embedded user interfaces.
Ensure that the user interface follows principles of accessible design: device-independent access to functionality, keyboard operability, self-voicing, etc.

9. Design for device-independence.
Use features that enable activation of page elements via a variety of input devices.

10. Use interim solutions.
Use interim accessibility solutions so that assistive technologies and older browsers will operate correctly.

11. Use W3C technologies and guidelines.
Use W3C technologies (according to specification) and follow accessibility guidelines. Where it is not possible to use a W3C technology, or doing so results in material that does not transform gracefully, provide an alternative version of the content that is accessible.

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

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

14. Ensure that documents are clear and simple.
Ensure that documents are clear and simple so they may be more easily understood.

Please see http://www.w3.org/TR/WAI-WEBCONTENT/wai-pageauth.html for a full description of these guidelines.