January 01, 2002
Web Accessibility: How to Apply Accessibility to Sites Old and New
If You Already Have a Web Site, the prep-work involved in retrofitting an existing Web site consumes more time than any other task. However, completing this preparation properly is the biggest key to the success of your project.
Take Inventory of Your Site's Content
It sounds simple, but before you can edit your site, you must be sure you know what's there. The type of content present may impact the decisions you make about navigation systems, organization of data, and the presentation of major elements.
Make a list of each occurrence and each file name for the following items:
Each image should be evaluated for purpose. Does it serve purely as decoration? Is it part of a visual navigation system? Does it convey information that isn't addressed in the document text?
After categorizing your images, determine which ones can be retained and which ones could be more appropriately converted to text. Those that remain require an ALT attribute for alternative text. Images that convey information not found elsewhere in the document should have a long description developed and linked with the LONGDESC attribute.
Forms
Analyze each form to ensure controls are grouped logically. Each control must have an associated label element in addition to any textual cues as to the intended content.
Java applets and other programmatic objects
Java applets and other programmatic elements are tempting to use for dynamic or interactive functions. It's important to remember, however, that these elements have a user interface of their own that requires as much attention to accessibility as your Web page does. In terms of content accessibility, the information presented or solicited must be available through alternative means.
Inline scripts
Scripts that provide content rather than visual effects—such as mouseovers—require an alternative means of information delivery for user agents that don't support scripting languages. For example, a JavaScript-based "calculator" (often found on financial sites) could have a link to a description of the formulas used in the computations, or to a table of possible results.
Framed content
Every frameset must have an accompanying NOFRAMES element for user agents not capable of or not set to render framed content. Additionally, the content provided through NOFRAMES must still make sense when viewed outside of the framed environment.
Dynamically generated content
Do the pages require specific user intervention before rendering, or is the process transparent to the user?
Check Each Inventory Item for Compliance
Download or print the list of checkpoints for the Web Content Accessibility Guidelines from the WAI program Web site at http://www.w3.org/TR/WD-WAI-PAGEAUTH/full-checklist.html . Work through each segment of your site inventory and apply the checkpoints pertinent to that element. For example, with each image, write text for the ALT attribute and provide a link to a long description using LONGDESC.
Put the pieces back together and review the entire site from a big picture perspective. Having started small with the individual element, you're now in a good position to review the site's global issues. Does it continue to pass the items in the checklist? Do any additional changes need to be made to enhance navigation, or provide alternative access to major portions of the site?
If You Are Creating a New Web Site
A new Web site gives you the perfect opportunity to provide a rich and rewarding experience to all of your visitors: able-bodied or with disabilities, those using traditional visual browsers, or users with screen readers, hand-held PCs, or even cellular phones.
Refer frequently to the guiding principles of accessible design listed in this chapter, which are taken from the WAI W3C Web Content Accessibility Guidelines. Consider printing the list of checkpoints for the W3C Web Content Accessibility Guidelines published by the WAI program, which is available at http://www.w3.org/TR/WD-WAI-PAGEAUTH/full-checklist.html.
Plan Effectively
You now know that having a clear and effective navigation system is a cornerstone of good accessible design. When planning the flow of information across your site, always think of how each page or section relates to the others, and how a user navigates between them.
Next week: Using HTML 4.0 principles to design your accessible sites.
Mike is Founder and Chief Technology Officer of WebABLE, Inc., an accessibility education and consulting firm.
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