Track user acquisition on exit - Google Analytics

Question

Is it possible to get a current users acquisition channel ( Facebook, Glassdoor, etc... ) and append it to a string during an onSubmit?

We have a careers page on our site with a search form that when filled out and submitted takes the user to a 3rd party software we use for our job listings. What we would like to do is track the users that submitted that form so we can see what channel lead to them looking for a job.

Ex:

User visits our Facebook page and clicks link to our site. Once on our site they fill out the job search form and is sent to our jobs listing site. We use JS to create the onSumbit url and fill it with the fields they answered and would like add another "acquisition" parameter to it with said acquisition.

Answer 1

You can store the referrer in a cookie if this is different from the domain of your website. In this way you can know where the user came from and use that value in the string you send to submit.