I run a subscription service on my website and I'd like to offer my users the option of signing up for a free service or taking a survey, or something of the sort in lieu of greenbacks. The only problem i have is that i really don't have a way to track if the user really completed the off site form. the only thing i was considering was opening the offsite form with a 1px frame at the bottom with some JS waiting for a url to load in the main frame of my choosing (form completed or some sort of finished, congrats page) then it would have to send a green light back to my site saying "hey this user completed the form give said user account donor access"

any idea's ?

thanks in advance
~U

Sounds like exactly the sort of thing Security is supposed to prevent. There is no reliable way you can know what your visitors did on someone else's site.

Do you have a relationship with this other site? If so, get them to send you the details. If not, I can't understand why this would cause you to offer something free.