Websites are made of pages. These testing tools scan the code on these pages one at a time when you enter your URL. There are a few services that offer to test your entire website, but read the find print as it may not include every page or human testing.
Accessibility is part of usability, and should be part of usability testing. Moving forward include accessibility in your design, build and test process.
Ridiculously Easy to Use Compliance Testing Tools
HTML Codesniffer — a “bookmarklet” for anyone. It works in all major web browsers and provides a detailed report of the error warnings and notices (items that may need to be reviewed by a human) indicating which parts of the code are causing red flags, and pointing to the relevant section of the WCAG or Section 508 spec and information on how to resolve the issue.
Additional tools can be found in this pages side bar (below or to the right, depending on your screen width).
Automated and Manual Testing
There are two layers to testing a webpage/site for accessibility compliance: automated testing and manual testing. You should use a combination of both.
Automatic testing will give you a good start and help you to understand some of the basics. Most tools have suggestions for correcting, links to the criteria, and general guidelines. But even the best automated testing tool can test only less than 25% that must meet WCAG 2.0 AA guidelines. And false positives are common and take time to weed out. The speed and convenience of Automatic Testing make it an integral part of testing. It is a good start but not a reliable evaluation of true accessibility. You may get slightly different results with different tools. Some tools do a better job of presenting the findings. It is a matter of preference. Also the tools are improving rapidly keep checking to see what is new.
Manual testing requires an understanding of the goals of the webpage/site being tested and the full context of the content to judge the accessibility. For example, the accuracy of closed captioning can only be determined by someone who is familiar with the subject material. The difference between the caption reading “Richmond CA” and Richmond VA” is only two letters and seem like a very small percentage off, but the information given to the person dependent on captioning is not equal.
Use both Automated and Manual Testing Together
When you use automated testing, eliminate false positives and check manually the rest of the elements using a checklist developed specifically for your website page you will get a clearer picture of it's accessibility. Many things you should be able to fix on the spot. For example adding alt text to images is a simple fix.
WCAG 2.0 Checklists
The WCAG 2.0 Guidelines Level A and AA lists more than 50 Success Criteria. Maintaining a checklist of satisfied criteria will help you manage your accessibility review process. The lists include short descriptions of each Success Criteria and several include links to reference documentation.
Having a checklist will get you started, but best to customize any list to cover what you are testing and only what you need makes the process a bit more manageable.
- The A11Y Project's Web Accessibility Checklist (a beginner’s guide to accessibility)
- McMaster University Web Page Checklist (Interactive checklist for WCAG 2.0 Level AA)
- WebAIM WCAG 2.0 Checklist (HTML and PDF)
- W3C WCAG 2.0 Checklist (HTML)
- Wuhcag Checklists by Level (HTML)
- Paul J Adam's WCAG 2.0 checklist (Interactive checklist with option to remove AAA checks from the list)
Test Early, Test Often
These simple tools will go a long way in teaching you about accessibility. Checking and ensuring accessibility is for every stage, but is most cost effective in development.
A reiterative approach to testing and correcting can give you ballance. Trying to test and fix all at once is not practical. The biggest misconception is that Accessibility is applied – it is an integral part of the creation.