Validate form before submitting

Hi Guys,

I have asked similar before but cant figure this out.

I have a form with mainly mandatory fields. There are two fields which are invisble unless 'other' is selected.

I have created a submit button which creates a email with the pdf as attachemrent. I am trying to get the submit button to validate the form before submitting. I cannot tell it to look at individual fields because if someone does select 'other' the visible fireld which appears becomes mandatory. I just need the form to check that everything has been filled in before the email is generated.

I have tried execValidate befoe and that doesnt seem to do anything.