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Chapter 6. Accessibility

Responsible web design includes making pages accessible even to users with disabilities, such as hearing, sight, cognitive, or motor skills impairments. Millions of people have disabilities that affect their access to information on the Web.

Many disabled users take advantage of assistive technologies for web browsing, both for input and output. For instance, some people have disabilities that make it impossible to input information using a standard keyboard or mouse. Instead, they may use a speech input device or a simple pointer attached to a headset. Others have disabilities that hinder the way they get information from a page. Vision impaired users may use a text browser (such as Lynx) in conjunction with software that reads the contents of the screen aloud. Some use devices that translate the text into Braille for tactile reading.

For most sites, accessibility is proper web design etiquette; for government web sites, it is the law. Section 508 (effective June 25, 2001) mandates that all Federal agencies' electronic and information technology be accessible to people with disabilities. For more information, see http://www.section508.gov.

By promoting accessibility for those with disabilities, content becomes more available to all users, regardless of the device they use to access the Web. This includes any alternative to the standard desktop graphical browser, such as palmtop computers or automobile dashboard browsing systems. Even users who have graphics turned off in their browsers to speed up download times will benefit from basic accessibility measures.

6.1. The Web Accessibility Initiative (WAI)

The World Wide Web Consortium (W3C) has launched its Web Accessibility Initiative (WAI), which aims to make the Web universally accessible. The WAI ensures that web technologies such as HTML and CSS support accessibility and promotes education and research to see that the standards are understood and followed.

In addition to overseeing the development of web technologies, the WAI has created recommendation documents that address three key audiences. First, the Web Content Accessibility Guidelines recommendation provides rules and techniques for web designers and authors on how to create content that is as accessible as possible. This chapter focuses primarily on these efforts. The Authoring Tool Accessibility Guidelines speaks to software developers making web authoring tools. Tools should make it easy to create standards-compliant content, as well as being accessible themselves. And third, the User Agent Accessibility Guidelines are for developers of browsing devices, from standard desktop graphical browsers to specialized assistive technologies.

These documents, as well as useful news, tools, and resources, are available at the WAI site (http://www.w3.org/WAI/).

6.1.2. The Guidelines

Web Content Accessibility Guidelines 1.0 is a thorough and highly detailed document. What follows here is a summary of the guidelines to point you in the right direction. For the details, read the original document online at http://www.w3.org/TR/WAI-WEBCONTENT/.

Guideline 1: Provide equivalent alternatives to auditory and visual content.

When providing text alternatives to images, video, and audio, be sure that the text has the same function and purpose as the media it is replacing. For example, if there is a graphic of an arrow that is used as a link to the top of the page, the alternative text should read "go to the top of the page," not "arrow." In addition, consider providing an auditory track (like a narrative explanation) for video media whose meaning is lost if it can't be seen.

Guideline 2: Don't rely on color alone.

Make sure your site is usable in black and white and colors contrast sufficiently.

Guideline 3: Use markup and style sheets and do so properly.

Great strides have been made in HTML and CSS technology to aid in accessibility, but they are only successful if they are used consistently to separate style from content.

Guideline 4: Clarify natural language usage.

Identify the language of the document and mark up exceptions such as foreign words, abbreviations, and acronyms. This makes it easier for speech devices and other assistive technologies to interpret the content.

Guideline 5: Create tables that transform gracefully.

The WAI recommends that tables be used for tabular data only. In addition, taking advantage of the more descriptive HTML 4 table markup can help users with disabilities navigate through complex tables. It is also useful to provide a summary of the table's contents in the <table> tag.

Guideline 6: Ensure that pages featuring new technologies transform gracefully.

Make sure that your page still works and makes sense without style sheets, JavaScript, applets, or other objects added to the page.

Guideline 7: Ensure user control of time-sensitive changes.

Any scrolling, blinking, or otherwise moving object should be able to be paused or stopped. Audio should be able to be paused or turned off as well.

Guideline 8: Ensure direct accessibility of embedded user interfaces.

This means that if you create your own site interface using a Java applet or Flash, the interface should follow basic accessibility guidelines.

Guideline 9: Design for device-independence.

Keep in mind that users may be using a variety of input devices, such as a mouse, keyboard, voice, head wand, or other device. Take advantage of technologies that allow shortcuts to links and elements on the page.

Guideline 10: Use interim solutions.

The W3C is developing technologies that will be useful just while older browsers are catching up to the current HTML 4.0/CSS2 way of doing things. These interim solutions ensure that older browsers operate correctly.

Guideline 11: Use W3C technologies and guidelines.

This one seems like a given, but be sure to use the current technologies since they have been developed and reviewed thoughtfully to support accessibility.

Guideline 12: Provide context and orientation information.

Provide clear labels for frames, sections of the page, and any complex page structure that requires extra explanation. Keep in mind what it would be like to use your site if you couldn't see it.

Guideline 13: Provide clear navigation mechanisms.

Take measures to ensure your site is easy to navigate, including clearly identified links, a site map or index, and consistent navigation.

Guideline 14: Ensure documents are clear and simple.

Everyone benefits from web pages that are laid out clearly and use simple language.

6.1.3. The Techniques

WAI has also compiled a list of very practical applications of each of these principles in a document called Techniques for Web Content Accessibility Guidelines 1.0. It provides specific techniques that address each of the checkpoints outlined in the general guidelines document. It also acts as a gateway to a number of other resources that describe the specifics on how HTML, CSS, and other core technologies address accessibility.

The WAI Techniques document is too vast to summarize here, but the following list presents a few simple measures you can take to make your pages more accessible:

If you would like to check how accessible your web page is, try running it through a validator, such as Bobby (http://www.cast.org/bobby/), that will scan your page and point out accessibility issues.

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