Understanding WCAG 2.0

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Understanding Guideline 4.1

Guideline 4.1: Maximize compatibility with current and future user agents, including assistive technologies.

Intent of Guideline 4.1

The purpose of this guideline is to support compatibility with current and future user agents, especially assistive technologies (AT). This is done both by 1) ensuring that authors do not do things that would break AT (e.g., poorly formed markup) or circumvent AT (e.g., by using unconventional markup or code) and 2) exposing information in the content in standard ways that assistive technologies can recognize and interact with. Since technologies change quickly, and AT developers have much trouble keeping up with rapidly changing technologies, it is important that content follow conventions and be compatible with APIs so that AT can more easily work with new technologies as they evolve.

Advisory Techniques for Guideline 4.1 (not success criteria specific)

Specific techniques for meeting each Success Criterion for this guideline are listed in the understanding sections for each Success Criterion (listed below). If there are techniques, however, for addressing this guideline that do not fall under any of the success criteria, they are listed here. These techniques are not required or sufficient for meeting any success criteria, but can make certain types of Web content more accessible to more people.

  • Avoiding deprecated features of W3C technologies (future link)

  • Not displaying content that relies on technologies that are not accessibility-supported when the technology is turned off or not supported.

Success Criteria for this Guideline: