Web Design in a Nutshell, 3rd Edition

Automated Testing Tools

If used with appropriate caution and judgment, automated tools can be very useful in determining accessibility problems in a site, in tracking progress over time, and for identifying possible issues that bear further investigation. The W3C maintain an extensive list of tools that are available for use in testing at http://www.w3.org/WAI/ER/existingtools.html. Keep in mind, however, that ability and disability are relative terms, so testing with black-and-white absolutes is sometimes problematic and always controversial.

It is important to remember with all of the automated testing tools that in some cases, you may see issues that do not apply to your particular site or that are difficult to test. For example, after scanning a page with JavaScript, many automated testing tools will state that you have used JavaScript in the page and therefore must include an alternate by using a <noscript>…</noscript> block in your page. The problem is that the automated test does not know what the script is doing, and what the result will be if the page is used with JavaScript both on and off.

As another simple example to illustrate the point: an automated testing tool can test for the presence of alternative text for an image. It can even test to see if there are other images with the same alternative text, and it can test to see if that image is part of a link. However, it cannot run any test that will determine whether or not the alternative text is appropriate for the image ...