How to check text input

Hi,

where can I find some sample code to verify the text typed by an user in a input box of a form ?

What I need is to verify that only "goot" caracters are used.

When the code finds ° à ò and hings like that should do nothing.

Thank you

Fabio

For inspiration look at this page and read it. It's just a few pages. Very nice written.

//babak