RE: [PHP] preg_match question: locating unmatched HTML tags

> I'm trying to build a regexp that would parse user-supplied text and > identify cases where HTML tags are left open or are not properly > matched-e.g., <b> tags without closing </b> tags. This is for a sort of > message board type of application, and I'd like to allow users to use > some HTML, but just would like to check to ensure that no stray tags are > input that would screw up the rest of the page's display. I'm new to > regular expressions, and the one below is as far as I've gotten. If > anyone has any suggestions, they'd be very much appreciated. Letting users enter HTML is a bad idea. Even if you only let them use <b> tags, they can still put ONCLICK and mouseover effects for the bold text to screw with your other users. Use a BB style code, such as [b] for bold, [i] for italics, etc. This way, you only match pairs and replace them with HTML and use htmlentities on anything else. This way an unmatched [b] tag won't be replaced with <b> and mess up your code. ---John W. Holmes... PHP Architect - A monthly magazine for PHP Professionals. Get your copy today. http://www.phparch.com/