Easiest Way to Create Logic for Phone Field ?

Hi there,
I was wondering if there is anyway i could control the phone number field. something like this:

user input phone number
if phoneNoDigits < 10
Give Error
Otherwise accept the number

That's all. I don't have much programing knowledge, so i was wondering what is the quickest and easiest way to do that?

Thanks,

Hi

There's one example of validating length in this thread. I vaguely remember another more specifically about phone numbers.

Bob

There's more info on Custom validation here in a paid tutorial.