Preventing submit until after required fields are entered

Hello all -

I'm using a standard button object with a little javascript on the click event to submit a form via email. I also have a validation routine implemented as a function in a script object to make sure the user completes all required fields.

The trouble I'm having is when the button is clicked, the email message always gets created in the email program, the data is attached, and the To: field is filled in with the specified address REGARDLESS of whether the validation routine found any unfulfilled required fields or not.

I know the validation routine is working properly. I just don't know how to prevent the email submission until after the validation verifies that all required fields have been filled out.

Anybody got any ideas on how I can tie the validation routine and the button click together? or is there a nice example that somebody can direct me to?