how to validate a form with javascript before eldarion submits

If a form has been marked 'ajax' with a class. It seems you can no longer validate it with a on('submit') handler if the eldarion-ajax handler attached first.

The on submit handler still runs but by that time eldarion-ajax has already submitted the from. So returning false of event.preventDefault is of no use to stop it.

Maybe a data attribute with a javacsript function to run to validate first?
