[PHP] Letters and Numbers limitation

Form takes parameter username, so I want to accept username taht includes only numbers and letters. How can I check if variable contains only letters and numbers? _ FREE pop-up blocking with the new MSN Toolbar – get it now!

Re: [PHP] Letters and Numbers limitation

Form takes parameter username, so I want to accept username taht includes only numbers and letters. How can I check if variable contains only letters and numbers? Use regular expressions. See the PHP manual (for PCRE or POSIX) for more. You'll also find a number of tutorials online about