Strict HTML Validation and Filtering in PHP

Question

I\'m looking for best practices for performing strict (whitelist) validation/filtering of user-submitted HTML.

Main purpose is to filter out XSS and similar nasties

Answer 1

I used HTML Purifier with success and haven't had any xss or other unwanted input filter through. I also run the sanitize HTML through the Tidy extension to make sure it validates as well.