HTML Codesniffer

This script checks HTML source code and detects violations of a defined coding standard.

Use it to check the internal consistency of your website code, making your site easier to maintain and update.

HTML_CodeSniffer is written entirely in JavaScript, does not require any server-side processing.

You can extend it to enforce custom coding standards by creating your own "sniffs".
To get you started, HTML_CodeSniffer comes with standards that enforce the three conformance levels of the Web Content Accessibility Guidelines (WCAG) 2.0 and the web-related components of the U.S. "Section 508" legislation.

An auditor interface is provided by a bookmarklet to let you try out these accessibility checks on any web page.

Get the HTML_CodeSniffer here.