How do I retain url parameters the entire time a user browses my site?

Better Answer:

session_start(); $lead = $_GET['lead']; $_SESSION['lead'] = $lead;

Then, create an additional field on the form, with the input hidden. For the value, I would echo out the $_SESSION, with a name that is easy to grab (lead works). then, wherever the form is processed, just add a line to grab the lead, and do with it what you want. –