36175 Pop up / no pop up script

I don't know if this is possible but here is what I would like. My site uses php, so I think is would have to be php or java. I have a program that will display a java pop-up signup form. If a person has already signed up I would like for this form to not pop-up. Perhaps this can be set with a cookie. This same pop-up would be on different pages of the site and would need to all use the same cookie so it wont show on any page that has it if the person has signed up. Let me know your ideas or if you need more information. Thanks.