[jQuery] [validate]Trigger validation before form submit?

I'm using this fantastic validation module:
http://bassistance.de/jquery-plugins/jquery-plugin-validation/ and I
wonder if there is a way to force validation before form submission.
I have a button, which my users have to click first, and if the
validation goes through then I will use window:print(); instead of
submitting the form
Regards
Raine