Phone validation before form submission - vendor recommendation?

Looking for a solution that works with Marketo forms to do phone validation before someone submits the form. The scenario would be when someone types in an invalid phone number, to throw an error and have them re-type it before they can submit the form. Evaluated Informatica but their solution does not currently work with Marketo forms. Is there a vendor that does? Would be even better if this can work on email as well as phone on Marketo forms. I know Etumos Verify works with email but looking for a solution that works with phone as well.