gravity form

This is a great question.
Unfortunately Gravity forms doesn’t have a JS hook on Valid Submissions.
There is one using PHP, but not Javascript.

So the way we do it is to use a Custom Thank You Page for the Gravity Form and create an action on that page.

You can also install this plugin to track gravity form submission events https://www.ads-software.com/plugins/gravity-forms-google-analytics-event-tracking/