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

User-submitted HTML isn't always valid, or indeed complete. Browsers will interpret a wide range of invalid HTML and you should make sure you can catch it.

Also be aware of the valid-looking:

and

click