I’m trying to write a function that states if a box is not checked,
onUnload, pop window.  Can’t seem to get it to work.

DETAILS
I have a suite of 4 pages which outline a product.
    See http://www.lumenresearch.com/1/2Q03CS/?gooAns for pages

The 4th page (see “terms tab”) has a check box.  This check box must
be checked in order for someone to click “purchase” and buy the
product.  I want to pop a page to someone who reviews any of these
four pages (there are many others in the site) and exits them without
checking the box on the “terms page” (representative of their choice
not to purchase).

If they came back again within the next 30 days, I don’t want to pop
them the page a second time.  (BTW, the pop is a short survey asking
them why they choose not to purchase the product.)

I’d like to ask for a JS script that I can hold in a file and call
from the pages that will mange this process.  I’d like the file/ code
to be expandable to additional products (also profiled in 4 similar
pages with same checkbox – but not yet developed).  However, when I
add it to other products, I don’t want to pop a page to the same
person every time they view a new product and don’t buy.  Any one
person should get no more than one popup during a 30 day period.

Thanks.