Top Accessibility Testing Tools for Web Designers

Accessibility testing tools can assist web designers in making their web site accessible to all visitors. Most of the online testers cannot test some checkpoints in the W3C Web Content Accessibility Guidelines at all and can only partially test others, however they all offer an easy way to quickly identify some problem areas. Using these combined with a sound understanding of Web Standards will help you in making your site accessible.

Until now, it has been impossible to have a completely valid Standards-based, accessible site with a default Mambo install. Mambo 4.7 changes that and with its release coming up soon, now is a good time to start evaluating your site and planning your changes to take advantage of the new flexibility 4.7 will offer.

W3C Web Accessibility Initiative provides a good list of online tools that can assist you with testing for accessibility. You can access the W3C WAI tools are here: http://www.w3.org/WAI/ER/tools/

Two tests that should be run on every site regardless of whether you are designing for accessibility or not:

W3C HTML Validator
http://validator.w3.org/
Tests HTML documents for conformance with HTML standards. The HTML Validation Service specifically tests for compliance with Level AA Checkpoint 3.2: “Create documents that validate to published formal grammars”, however it will pick up other accessibility errors such as missing ALT attributes and invalid field labels.
The validator is not 100% accurate but passing validation with no errors or warnings is a good indicator that your code is Standards-compliant.

W3C CSS Validator
http://jigsaw.w3.org/css-validator/
Tests cascading style sheets to ensure they conform with CSS standards. The CSS Validation Service specifically tests for compliance with Level AA Checkpoint 3.2: “Create documents that validate to published formal grammars”.
The validator is not 100% accurate but passing validation with no errors or warnings is a good indicator that your code is Standards-compliant. One weakness with the validator is that it can get confused if the CSS version is not specified or if the CSS uses a mix of CSS 1 & 2 for example. This can result in inaccurate reports.

Other online testing tools include the following:

Cynthia Says
http://www.cynthiasays.com/
Cynthia Says is the online page-by-page accessibility evaluator by HiSoftware. It tests many of the W3C Web Content Accessibility Guidelines. It cannot test all and only partially tests some. The equivalent downloadable site-wide accessibility evaluator is AccVerify.

WAVE
http://wave.webaim.org/index.jsp
The WAVE is a page-by-page accessibility evaluator by WebAIM. It tests many, but not all, of the W3C Web Content Accessibility Guidelines.

ATRC Accessibility Checker
http://checker.atrc.utoronto.ca/index.html
The ATRC Accessibility Checker is an online page-by-page accessibility evaluator, previously called A-Prompt. It tests many of the W3C Web Content Accessibility Guidelines. It does not test against all the guidelines.

HERA
http://www.sidar.org/hera/index.php.en
HERA is an online page-by-page accessibility evaluator. It tests many of the W3C Web Content Accessibility Guidelines, but not all. It does however provide good information on on the type of manual testing required.

Web Accessibility Toolbar
http://www.nils.org.au/info.aspx?page=614
The Web Accessibility Toolbar, developed by Vision Australia, provides a variety of features that assists in testing a site. It can aid in testing many of the W3C Web Content Accessibility Guidelines although it is somewhat limited in what guidelines it can test. Its a toolbar that can only be installed on Internet Explorer and Opera.

FireFox Web Developer Extension
http://chrispederick.com/work/webdeveloper/
This Firefox browser Add-On provides a variety of features that assists in testing a site. It can aid in testing many of the W3C Web Content Accessibility Guidelines. It cannot test against all.
(It is also a very useful tool for any template designer to have).

JuicyStudio Colour Contrast Analyser
http://juicystudio.com/services/colourcontrast.php
Tests pages against the W3C algorithm for colour contrast. The JuicyStudio Colour Analyser specifically tests for compliance with Level AA Checkpoint 2.2: “Ensure that foreground and background color combinations provide sufficient contrast when viewed by someone having color deficits or when viewed on a black and white screen”.
The analyser will give two values: a colour brightness value and a colour difference value. Colour brightness should be above 125, and colour difference should be above 500.
Note: The W3C algorithm is very strict and some colours may fail even though they can be viewed by people with colour contrast impairments.

JuicyStudio Readability Test
http://juicystudio.com/services/readability.php
The JuicyStudio Readability Test specifically tests for compliance with Level A Checkpoint 14.1: “Ensure language is clear and simple”.
The test provides a table of values, such as number of words, sentences, paragraphs etc. The table also provides the page’s Gunning Fog index, the Flesch Reading Ease and the Flesch-Kincaid reading grade level.

Vischeck
http://vischeck.com/vischeck/vischeckURL.php
Shows pages as they would look to someone with common colour disorders. Vischeck specifically tests for compliance with Level AA Checkpoint 2.2: “Ensure that foreground and background color combinations provide sufficient contrast when viewed by someone having color deficits or when viewed on a black and white screen”.
Vischeck has difficulties testing pages with CSS, flash and frames.

If you have experience with other good accessibility testing tools add a comment and tell us about them.