ASP.NET 3.5 For Dummies®

12.4. Meeting Accessibility Requirements

Increasingly, Web sites created for government agencies must meet accessibility requirements. These standards ensure that the site is usable by people who have difficulty seeing, hearing, moving, or processing images. The goal is to generate online documents that specialized browsers, such as screen readers and braille displays, can handle easily.

In the United States, people often refer to Section 508 of the Rehabilitation Act of 1973, more commonly known as Section 508. In 1999, the W3C produced its Web Content Accessibility Guidelines 1.0 (WCAG 1.0). You can read the document at www.w3.org/TR/WAI-WEBCONTENT/.

Accessibility and usability have many issues in common. See the upcoming section, "Increasing a Page's Usability," for ways to make pages easier to use for all visitors.

12.4.1. Alternate text for images

For the most part, ASP.NET server controls meet accessibility requirements, but a great deal depends on the page developer. For example, you wouldn't want to create problems for blind — or colorblind — readers by instructing them to click a red or a blue image to continue.

A key requirement for accessibility is a text equivalent for images and multimedia content. The ASP.NET Image, ImageButton, and ImageMap controls include an AlternateText property in which you can enter an explanation of the image. If your layout uses images ...