UserPro Plugin - stop form submit based on ajax response if field is blank

We're using the UserPro Plugin. Right now if a user deletes what's in a specific field in their profile so it's blank, jquery detects the input change and that's it's blank, and runs an ajax function. Based on this ajax response, it either shows a warning message and changes the data-required attribute to 1 or does nothing. This is working. What we need though, is this same function to run when the form is submitted, and either allow or deny the form submission based on the ajax response, and show the same warning message to the user.