Simple php/js form-script

I need a php / javascript -form for campaign site.

Campaign's idea is choose a present and then choose a magazine.

1. Choosing a present: two present with radio button (customer can only choose one present)

2. Choosing a magazine: After choosing a present customer clicks magazine cover and page moves to certain url.

Every combination of present+magazine has it's own url. Form script should work that way that it knows which url it uses when customer has choosed present and magazine. Script should also remind customer that he has to choose a present before clicking the magazine.

Form doesn't have to post any data. It only has to know right target url when customer is clicking the magazine cover.

Example for target url: http://www.company.com/offer=42341233

There are 28 differend combinations of magazine+present.

No graphic designing needed. Only xhtml and form functions.