Check HTML Source Code Conforms to Coding Standard
HTML_CodeSniffer will provide a list of known and potential violations to the calling script. It also comes with a pop-up auditor interface, accessible via a bookmarklet, letting you browse through messages emitted from one of the defined standards. Where possible, the auditor also points you to the HTML element causing the problem. HTML_CodeSniffer is released under a BSD-style licence.
License: BSD License