Auto Fill Referrer field from URL

[Tory H]

Hi,

If somebody goes to my forum with the following kinda URL

http://www.myforum.com/register.php?referrerid=xxx

The name of that referrer is placed automatically in the field where referrer is on reg page from a cookie. I have removed the first step to the registration (agree rules), and now this is not working.

I just want the value taken directly from the URL, like this

$referrername = $_GET('referrerid')

but with all the code I see in register.php I'm lost as to where to place such code (if indeed that is correct), and how to make it secure.

Ideally that particulary form field would be hidden anyway,

Any ideas?

Thanks
Matthew