HTML Purifier is a standards-compliant HTML filter library written in PHP. HTML Purifier will not only remove all malicious code (better known as XSS) with a thoroughly audited, secure yet permissive whitelist, it will also make sure your documents are standards compliant, something only achievable with a comprehensive knowledge of W3C’s specifications.
HTML Purifier is open-source and highly customizable. The current version of HTML Purifier is 4.1.1, compatible with PHP 5.0.5 and up (all code is E_STRICT compliant).
HTML Purifier is a great library to integrate with existing CMSes and other applications or WYSIWYG editors. Currently, plugins available for applications are – Phorum, MODx, Drupal, WordPress and bbPress, Joomla, CodeIgniter, Symfony, CakePHP.
HTML Purifier available for multiple ways of downloading and installing – Standard, Lite Distribution, Standalone Distribution.