[RESOLVED] Validate field with letters or numbers only

[shawjames]

I have been trying to figure this out, and cannot seem to find any examples that do exactly what I need to do.

I want to validate a field to make sure it has only letters or numbers. No other characters or spaces.

I will use preg_match, but I need help with the expression.

Can anyone help me with an expression that would work?

[NogDog]

[man]ctype_alnum/man

(You can use [man]strlen/man to verify the number of characters.)

[shawjames]

ctype_alnum() - that works!