Date: 12/21/07 (Java Web)    Keywords: php, css, html

strip_tags() in PHP has several problems. It doesn’t recognize that css within the style tags are not document text. It will not remove HTML entities or content within script tags. strip_tags() fails for invalid HTML. In short strip_tags() is not advisable to use except for trivial cases. The best solution I have come across is [...]

Source: http://blog.taragana.com/index.php/archive/how-to-fix-buggy-php-strip_tags-function/