Possible to pass through a javascript variable through a form submission?

Hey there! I have a form on one domain that has a thank you page on an external domain. I am trying to pass through a variable.

Currently the URL parameter looks like this:


I would like to add an additional variable to that URL.

Page here: Tax Sale Blueprint

Setup a PHP file as your thank-you page, it reads the current GET variables into an array, then adds whatever you want to that, and then forwards the traffic to your desired page with your GET variable added.

Makes sense, thanks