PHP處理HTML安全

HTML Purifier
http://htmlpurifier.org/
HTML Purifier is a standards-compliant HTML filter library written in PHP.

Safe HTML
http://chxo.com/chxo-scripts/safe_html/index.html
http://pear.php.net/package/HTML_Safe
safe_html() is a free php function that takes a conservative approach to sanitizing user input while still allowing some markup through.