"Accessibility" is specific to making sure that users who have difficulty seeing, hearing, and making precise movements can use a Web site by facilitating the use of "common assistive technologies," with specific reference to Section 508 (a requirement for all federal Web sites).

About 8% of the general population would have difficulty using a Web site as most people do, which breaks down like this:

EN: My position has long been that making the site accessible is a technological rather than a design challenge, and that the software and devices provided to disabled users should be designed to make all Web sites usable, regardless of their design. The degree to which assistive technologies are poorly designed requires designers to adapt their sites to suit these software packages.

1. Comply with Section 508 (5:2)

Section 508 of the Rehabilitation Act requires all federal Web sites to "take into account the needs of all users."

EN: Since this manual is for developers of government Web sites, who are required to comply with this act, it's not optional at all for them. I would agree it's a good idea for all sites to consider the guidelines, especially if the disabled are a significant portion of their intended audience.

2. Design forms for users using assistive technologies (5:2)

Online forms (those that collect data from users via standard inputs such as text fields, select objects, etc.) are specifically emphasized as an area where disabled users encounter problems and that designers can use specific techniques to facilitate accessibility.

3. Do not use color (alone) to convey information (5:4)

Elaboration: In addition to individuals with disabilities with visual acuity, it is estimated that 8.5% of the population has some degree of difficulties discerning color (color-blindness) or discerning subtle differences among shades of color (especially in the blue-green area of the spectrum)

4. Enable users to skip repetitive navigation links (4:2)

It is suggested that disable users find it "tedious" to have common links (such as a navigation bar) read to them each time they visit a page. The guidelines indicate "users should be able to avoid these links if they desire to do so" ... though no approach or technique is provided to illustrate how this can be accomplished.

5. Provide text equivalents for non-text elements (4:2)

This guideline is based on ALT tags, but is made vague to include other media where possible. Of particular importance, the alternate text should be an equivalent - the example is text that describes the content of an image in detail (rather than the word "picture" as ALT text)

6. Text plug-ins and applets for accessibility (4:2)

An indication that the user of applets and plug-ins is a particular area of difficulty for disabled users, and that they should be "tested for accessibility" - no indication of how these tests should be conducted or what alternatives can be provided to accommodate the disabled user.

7. Ensure scripts allow accessibility (3:2)

Script-driven events (JavaScript DHTML tricks) are another specific area of concern (again, this comes without advice or a solution).

8. Provide equivalent pages (3:2)

If it is not possible to provide equivalent information in the context of a page, a link should be provided to a text-only page for disabled users.

9. Use client-side image maps (3:3)

Server-side image maps are another area where the disabled are stymied.

EN: This guideline comes from 1998, when client-side image maps were new. Presently, the user of server-side maps is highly unusual. However, it is possible to use script-driven image maps, which are bad for usability and accessibility.

10. Synchronize multimedia elements (3:2)

A recommendation that video media should have a closed-caption alternative, and that any captions in media elements (Flash, for example) should be carefully synchronized.

11. Do not require style sheets (3:1)

Organize documents so they are readable without requiring an associated style sheet

EN: Another guideline from 1998. I believe that since them style sheets are actually encouraged to improve usability, but the order in which content is placed in the source document should have a logical order (rather than random).

12. Provide frame titles (2:2)

When using frames, ensure that there is a title for each frame to facilitate navigation. (EN: when frames were first introduced, it was suggested that a element was not necessary, which meant these documents had no titles or metadata.)

When using frames, ensure that there is a title for each frame to facilitate navigation. (EN: when frames were first introduced, it was suggested that a

13. Avoid screen flicker (2:1)

Five percent of epileptics have photosensitivity (flashing lights can invoke a seizure). A frequency of between 2 and 55 Hz (cycles per second) has been identified as a problem range for these individuals.