Interpretation

(a) A text equivalent for every non-text element shall be provided (e.g., via “alt”, “longdesc”, or in element content).

This permits a non-graphical browser be able to display text in place of the non-text element.
This also permits a text-reading applications to read out the content of a web page.

(b) Equivalent alternatives for any multimedia presentation shall be synchronized with the presentation.

This means that the text caption of a multimedia presentation should be synchronized with the video/audio portion.
It permits assistive technology (braille, for example) present material in a multimedia presentation at the same time as the multimedia version.

(c) Web pages sheel be designed so that all information conveyed with color is also available without color, for example from context or markup.

This makes color enabled pages accessible to people who cannot see colors. For example, text-based browsers that are monochrome.

(d) Documents shall be organized so they are readable without requiring an associated style sheet.

Forget about the fancy CSSs. A web page should be readable without CSSs.
This makes the presentation of the content of a web page more self contained.
A CSS controls how information is presented, but not the information itself. If a CSS has impact on the availability of the information, then the CSS does too much.

(e) Redundant text links shall be provided for each active region of a server-side image map.

First of all, it mentions “text links”. This means no bitmap buttons, no fancy Flash animation. This makes it easy for a text-based browser present the links.
This clause makes an image map (a graphical element) accessible to users who do not have graphics access.
An image map is server-side when all the browser does is to send the coordinate of a click. This means there is no alt-text to present! As a result, the redundant text links are necessary.

(f) Client-side image maps shall be provided instead of server-side image maps except where the regions cannot be defined with an available geometric shape.

This means there is a preference of client-side. This is because with a client-side image map, it is possible to add alt-text to each link, which makes it visible to text-only browsers, or to text-reader assistive software.

(g) Row and column headers shall be identified for data tables.

Without row and column headers, a table can be difficult to to interpret, even to a person without disabilities..
To a text-to-speech reader, a table without row and column will just mumble items in the table. However, with both row and column headers, a text-to-speech program can remind the listener what each is in each row.

(h) Markup shall be used to associate data cells and header cells for data tables that have two or more logical levels of row or column headers.

This utilizes the headers attribute of a cell to link it back to the associated header <TH>. An assistive program can, then, announce the headers (row and column) of any cell in a table, making it much easier to interpret a cell in a large table.

(i) Frames shall be titled with text that facilitates frame identification and navigation.

The <frame> tag has an optional attribute name. this clause says that all frames must utilize this attribute. Assistive programs utilize this attribute to announce the name of a frame.

(j) Pages shall be designed to avoid causing the screen to flicker with a frequency greater than 2Hz and lower than 55Hz.

Flicker in this range of frequency can cause seizure with people who are photosensitive epilepsy.

(k) A text-only page, with equivalent information or functionality, shall be provided to make a web site comply with the provisions of this part, when compliance cannot be accomplished in any other way. The content of the text-only page shall be updated whenever the primary page changes.

First of all, this text-only page is required only if there is no other way to comply with the section. In many cases, there is no need to provide a text-only page.
On the other hand, this is a sure way to make a web page comply with this entire section.
This is especially easy to do when web pages are dynamically generated.

(l) When pages utilize scripting languages to display content, or to create interface elements, the information provided by the script shall be identified with functional text that can be read by assistive technology.

This topic is rather advanced at this point. We will defer the discussion of this clause in other modules.

(m) When a web page requires that an applet, plug-in or other application be present on the client system to interpret page content, the page must provide a link to a plug-in or applet that complies with §1194.21(a) through (l).

This clause is necessary for web pages that require special client-side software to interpret the content.
Special content includes portable document format (PDF) files, real-media and etc.
Essentially, if a web page includes documents that cannot be interpreted by a browser and its assistive programs, a link must be provided to a software tool that can interpret the content.

(n) When electronic forms are designed to be completed on-line, the form shall allow people using assistive technology to access the information, field elements, and functionality required for completion and submission of the form, including all directions and cues.

This is one is fairly self explanatory.
We’ll discuss the exact techniques to do this in another module.

(o) A method shall be provided that permits users to skip repetitive navigation links.

This clause states that a web page should have links to skip the level-by-level “upward” links. In other words, it should provide links to skip “up” levels at a time.

(p) When a timed response is required, the user shall be alerted and given sufficient time to indicate more time is required.

First of all, there should be a way to indicate more time is allowed.
The amount of time needed to indicate more time is needed should be accessible within the time limit.

4 Interpretation