HTML_CodeSniffer

This tool, made available by Squiz, is a client-side script that checks HTML source code and detects violations of a defined coding standard. The tool can be used by running HTML_CodeSniffer inside a browser after a bookmarklet has been added to the bookmarks bar. The sample public version will check a site for conformance with the Web Content Accessibility Guidelines version 2.0. Selecting individual issues within the report will indicate the relevant visual element on the page, display the problematic markup and offer a link to suggested techniques for resolving the issue.