"nullifying" php and html tags?

Hello. I just finished creating a simple input form in which the contents of a textarea get written to a file which in turn gets read by a particular page. is there anyway to "disable" any html or php tags that the user might have typed in? it seems pretty dangerous to allow a user to enter any amount of php programming at their will. something as simple as a function that strips all <'s and >'s would work just as well i would imagine. thanks! -mark __________________________________________________ Do You Yahoo!? Yahoo! Sports - Coverage of the 2002 Olympic Games http://sports.yahoo.com