form validation

Re: form validation

All I want now is a way to add a 'prefix' to a 2 digit number the user is going to enter.

Ex.

the user enters 34, and I want a php string manipulation function (is that what they're called?) to add a ABC-TT- infront, and returning ABC-TT-34.

Originally, I wanted the user to add the whole string, but that would require input validation, and I thought, it'll be easier if I just let the script add the prefix ...

I don't mind doing some reading, but i'm not sure what to read ...