Accessibility Themes

The two overarching themes of accessible web design are

1. Ensuring graceful transformation
2. Making content understandable and navigable

Graceful Transformation

Pages that transform gracefully remain accessible despite any physical, sensory, or environmental constraints or technological barriers. Additional terms that describe graceful transformation include backwards compatibility and trans-usability. The idea is: Can the document (page) be used by a variety of people under a variety of conditions, with a variety of (dis)abilities? Keys to designing pages that transform gracefully include:

• Separate structure from presentation.
• Provide text (including text equivalents for all images). Text can be rendered in ways that are available to almost all browsing devices and accessible to almost all users.
• Create documents that work even if the user cannot see and/or hear.
• Provide information that serves the same purpose or function as audio or video in ways suited to alternate sensory channels as well.
• Create documents that do not rely on one type of hardware. Pages should be usable by people without mice, with small screens, low resolution screens, black and white screens, no screens, with only voice or text output, etc.

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 image maps, proportional scroll bars, side-by-side frames, 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). Keys to designing pages that transform gracefully include:

• Consistent navigation methods, sequence, and terminology site-wide
• Ability to skip redundant navigational links
• Site maps and site/page descriptions
• Appropriate use of color

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