form validation driving me bonkers!

[admin]

Hi!

I'm trying to validate a simple guest book.
It must:

a) produce an alert when the email address is invalid;
b) produce an alert when a catagory of visitor is not selected;
c) produce an alert box informing them of the info that they have put in.

I can only get any 2 of the following working.. never all three!

Any ideas?

the script and html page are attached

Thanks

luds