InfoPath Dev

Hello, I have a Infopath 2013 form. I wanted to know how to highlight the fieldname in red color(or any) when the submit button is clicked. There is already a red asterisk appears when submit buttons clicks but my form is very complex, that's why it's hard to find the blank field. any help would be really appreciated.

use a formatting rule you can change text or cell color

That was my first step. But i need to apply formatting rule on button click event.

This is something I do pretty often.

 You'll need to add several rules on your submit button, which set a or some hidden fields.  Then on your fields you'll need a formatting rule which knows when a field should or should not have been completed.

Example attached.