It is desirable to maximise the accessibility of Web sites in order to ensure that Web resources can be accessed by people who may suffer from a range of disabilities and who may need to use specialist browsers (such as speaking browsers) or configure their browser to enhance the usability of Web sites (e.g. change font sizes, colours, etc.).
Web sites which are designed to maximise accessibility should also be more usable generally, (e.g. for use with PDAs) and are likely to be more easily processed by automated tools.
Although the development of accessible Web sites will be helped by use of appropriate templates and can be managed by Content Management Systems (CMSs), there will still be a need to test the accessibility of Web sites.
Full testing of accessibility with require manual testing, ideally making use of users who have disabilities. The testing should also address the usability of Web sites as well as its accessibility.
Manual testing can however be complemented with use of automated accessibility checking tools. This document covers the use of automated accessibility checking tools.
The W3C WAI (Web Accessibility Initiative) have developed guidelines on the accessibility of Web resources. Many institutions are making use of the WAI guidelines and will seek to achieve compliance with the guidelines to A, AA or AAA standards. Many testing tools will measure the compliance of resources with these guidelines.
The best-known accessibility checking tool was Bobby which was renamed as WebXact, a Web-based tool for reporting on the accessibility of a Web page and its compliance with W3C's WAI guidelines. However this tool is no longer available.
HiSoft's Cynthia Says provides an alternative accessibility and Web site checking facility - see <http://www.contentquality.com/>.
Note that it can be useful to make use of a multiple checking tools. W3C WAI provides a list of accessibility testing tools at <http://www.w3.org/WAI/ER/tools/>.
When you use testing tools warnings and errors will be provided about the accessibility of your Web site. A summary of the most common messages is given below.
As mentioned previously, automated testing tools cannot confirm that a resource is accessible by itself - manual testing will be required to complement an automated approach. However automated tools can be used to provide an overall picture, to identify areas in which manual testing many be required and to identify problems in templates or in the workflow process for producing HTML resources and areas in which training and education may be needed.
Note that automated tools may sometimes give inaccurate or misleading results. In particular: