is_alpha_numeric ?

Hello everyone, I'm trying to determine if an argument is alphanumeric. Is there a function to do this? I thought PHP had a IS_ALPHA_NUMERIC function, but I can't seem to find it anywhere. Was it wishful thinking ? Please help. If you do know of this function, then please send me the syntax. is_alpha_numeric($string) is not working. If you do know of another way to this, then please send me that as well. My expected string has the form 'A200A'. Both, letters and numbers, will change depending on the item. The value will ve passed via a hidden form. Thanks in advance. -John __________John Monfort_________________ _+-----------------------------------+_ P E P I E D E S I G N S www.pepiedesigns.com "The world is waiting, are you ready?" -+___________________________________+-