W3C WAI ER
This is a little service to check web pages for some of the Web Content Accessibility Guidelines. It correctly identifies some, but not all, accessability problems in HTML pages. It also falsely reports some stuff. I hope to fix that over time.
It's mostly just a repackaging of the WAI example in the Schematron materials by Rick Jelliffe, Academia Sinica Computing Centre. I modified wai.xml and schematron-report to use XHTML with namespaces, for compatibility with tools like tidy. Rick notes that his WAI schema is incomplete, and I haven't fixed that (yet).
If your document is already XHTML, you can skip to the next step.
NOTE: the result is XHTML, but this HTTP server might label it as text/xml, so you might have to do something like save it locally with a .html extension to get it to look right in your client. I hope to fix this soon.