Web accessibility means that people with disabilities can use the Web. More specifically, Web accessibility means that the Web is designed so that people with disabilities can perceive, understand, navigate, and interact with it effectively, as well as create and contribute content to the Web.
There are millions of people who have disabilities that affect their use of the Web. Currently most Web sites have accessibility barriers that make it difficult or impossible for many people with disabilities to use the site. However, if Web sites and Web software were made accessible, people with disabilities could use the Web effectively.
Web accessibility addresses all disabilities, including visual, auditory, physical, speech, cognitive, and neurological disabilities. For more information, see the "How People with Disabilities Use the Web" document that describes how different disabilities affect Web use and scenarios of people with disabilities using the Web.
Web accessibility can also benefit organizations and people without disabilities. For example, a key principle of Web accessibility is flexibility to meet different needs, situations, and preferences. Flexibility benefits all people who use the Web, including people without disabilities in different situations (such as a slow connection), people with temporary disabilities (such as a broken arm), and some older people. For more information, see "Developing a Web Accessibility Business Case for Your Organization."
The Web plays an increasingly important role in education, employment, commerce, government, and recreation. An accessible Web that allows people with disabilities to actively participate in society is essential for equal opportunities in many areas.
The Web offers the possibility of unprecedented access to information and interaction for people with disabilities. For more information, see the Web Accessibility is a Social Issue section of "Developing a Web Accessibility Business Case for Your Organization: Social Factors".
Web accessibility is required by law in some cases. For a list of laws and policies around the world, see "Policies Relating to Web Accessibility."
Web accessibility depends on several different components of Web development and interaction working together, including Web software (tools) and Web developers (people). The main reason that many sites are not accessible is that Web software does not adequately support accessibility and Web developers are not aware of or do not understand basic accessibility issues.
To help clarify accessibility issues and define accessibility solutions, the Web Accessibility Initiative (WAI) develops guidelines that are international standards for Web accessibility.
For more information, see "Essential Components of Web Accessibility," which explains how the different components work together and how they are covered in the different WAI guidelines.
The effort required to make a site accessible depends on many factors, including the type of content, the size and complexity of the site, and the development tools and environment.
Many accessibility features are easily implemented when planned from the beginning of a development project or redesign project. However, retrofitting existing sites can require significant effort, especially sites that are not "coded" properly with standard XHTML markup, and sites with certain types of content, such as multimedia.
"Implementation Plan for Web Accessibility" lists basic steps in making an organization's site accessible.
When developing or redesigning a site, evaluating accessibility early and throughout development can find any accessibility issues early when it is easier to address them, rather than waiting until near the end of development. Simple techniques, such as changing settings in a common browser, can determine if a Web page meets some accessibility guidelines. A comprehensive evaluation to determine if a site effectively meets all accessibility guidelines is much more complex.
"Evaluating Web Sites for Accessibility" includes a section on preliminary review with techniques to quickly assess some of the accessibility issues on a site, and a section on conformance evaluation with general procedures and tips for evaluating conformance to accessibility guidelines.
There are automated tools that help with evaluation; however, no tool alone can determine if a site meets accessibility guidelines. Knowledgeable human evaluation is required to determine if a site is accessible.
For More Information
The WAI Web site provides guidelines and support resources to help implement the guidelines, such as "Quick Tips to Make Accessible Web Sites." Other organizations also provide resources to help make the Web accessible.
Notes on Terminology
Web "content" generally refers to the information in a Web page or Web application, including text, images, forms, sounds, and such. More specific definitions are available in the WCAG documents, which are linked from the Web Content Accessibility Guidelines (WCAG) Overview.
- Web browsers, media players, and other "user agents"; for more information, see User Agent Accessibility Guidelines (UAAG) Overview.
- Authoring tools that creates Web sites; for more information see, Authoring Tool Accessibility Guidelines (ATAG) Overview.
- Evaluation tools that determine if a Web site meets standards and guidelines; for a list of accessibility evaluation tools, see Evaluation, Repair, and Transformation Tools for Web Content Accessibility.
- Overview of the Web Accessibility Initiative (WAI) Slides links to slides introducting Web accessibility
- Other related pages are linked throughout this document