While there is no substitute for true user testing when it comes to web accessibility testing, there is definitely a lot of room for tools that can aid us in at least testing and confirming those issues that can be tested by automated testing tools. Through my years as a web developer it has always taken some effort to find tools that I can rely on and that provides useful feedback that makes developing and designing accessible web sites and web applications a little easier, not that is really that hard. So, to make this process a little simpler for everyone dedicated to standards and accessibility and hopefully expanding this audience, I have compiled a list of tools that will greatly ease your efforts. Enjoy!
The first place to start would be to ensure that your HTML/XHTML code validates. The best place for this is the validator of the World Wide Web Consortium. For the validator you have a variety of options from validating via a URL, uploading a file or using direct input via a text field. You also have a variety of additional options you can set for example setting the character encoding, the document type and various formatting options for the way the results are displayed.
Your next stop should be the W3C's CSS validator. While valid CSS and HTML/XHTML does not guarantee accessibility automatically, it is definitely a huge step in the right direction. As with the HTML validator mentioned before, the CSS validator also provides you various options for validating your CSS as well as how the results are displayed.
This is one not many people might have thought about but, for users with a variety of disabilities RSS and Atom feeds are a God send and they rely on these feeds to get the low down on what interests them,
so it is well worth ensuring your feeds validate. This tool does not provide as many options as the other two validators but, does allow you to validate a feed via either a URL or direct input. Well worth checking out.
Want to do your HTML/XHTML validation straight inside your browser? Well then there is no better tool the the Firefox HTML Tidy plugin. "HTML Validator is a Mozilla extension that adds HTML validation inside Firefox and Mozilla. The number of errors of a HTML page is seen on the form of an icon in the status bar when browsing. The extension can validate the HTML sent by the server or the HTML in the memory (after Ajax execution)"
The HiSoftware Cynthia Says portal is a web content accessibility validation solution. It is designed to identify errors in your content related to Section 508 standards and/or the WCAG guidelines. This free tool meant for educational purposes, is an online test which only validates one page at a time.
While the above tool evaluates 1 page at a time the Functional Accessibility Evaluator can evaluate a complete site up to three levels deep! All you have to do to gain access to these features is to sign up for a free user account. It can also store combined reports of multiple sites into one report.
It is suggested by Jeremy Sydik that you go for the 4.0 Beta version of this tool as apposed to the 3.0 version. As the W3C tools does so does WAVE provides a variety of ways to test your pages. "WAVE is a free web accessibility evaluation tool provided by WebAIM. It is used to aid humans in the web accessibility evaluation process. Rather than providing a complex technical report, WAVE shows the original web page with embedded icons and indicators that reveal the accessibility information within your page."
The Mozilla/Firefox Accessibility Extension makes it easier for people with disabilities to view and navigate web content. Developers can use the extension to check their use of structural and styling markup that support functional web accessibility.
As the learning curve for using screen readers are very high, not to mention the cost, it is generally difficult to test your site with screen reader software. However, lucky for us, Fangs comes to the rescue and acts as a screen reader emulator right from inside the Firefox browser.
Like Ruby, Rails, accessibility? Why not give the Ruby Accessibility Analysis Kit a whirl. "RAAKT is a toolkit to find basic accessibility issues in HTML documents. RAAKT can be used in an automated quality assurance process to increase developer awareness of accessibility issues and increase speed in accessibility analysis. RAAKT is written in Ruby and can therefore easily be integrated with Ruby on Rails."
TAW (Web Accessibility Test) is a tool for the analysis of Web sites, based on the W3C - Web Content Accessibility Guidelines 1.0 (WCAG 1.0).
One of the things they offer is to allow you to choose which level of the WCAG standard you want to test for A, AA or AAA.
aDesigner is a disability simulator that helps designers ensure that their content and applications are accessible and usable by the visually impaired. Voice browsers and screen readers read aloud the text on Web pages and are used by visually impaired people. However, these devices are less effective with certain kinds of content, such as highly graphical material. Web developers can use aDesigner to test the accessibility and usability of Web pages for low-vision and blind people. aDesigner also helps users to check accessibility of ODF documents and Flash content. It also has accessibility information (MSAA/IA2) inspection functions.With the above tools you now a have a formidable tool set to go forth and develop and design websites and application that adhere to the standards as well as reach the level of accessibility your audience demand. If the list above is not enough for you, then you can find and exhaustive list of both free and commercial tools you can use at http://www.w3.org/WAI/ER/tools/. And of course, if I missed something you really believe should be here then post a note in the comments area.