How to create a validation Form overlay on top of a Form before submit?

[hiikung]

Hi,

I want to ajax a validation form(2) kind like login form overlay on the present form(1) before the form(1) submit.
So my question is:

if the validation form(2) fail, how stop the form(1) from proceed submit? I had tried with form.result = false, it still submit with validation. but I want the form to stop at the moment validtion form(2) return fail.
And if it return true, then the form(2) will proceed and save the record in db.

Thank you.