[Javascript] Passing Selection Data

[javascript@xxxxxxxxxx (greg@xxxxxxxxxxx)]

Is it possible to pass selections from a pop-up window to a main page with JavaScript?  On the following page

http://www.cbshome.com/IRP/listing/ListingSearch.asp?ListingType=1&SearchType=Geographic

a map link provides a pop-up window with a map.  When you click on sections of the map, the information of the selection is passed back to the main page.  How is this done?  I've got a file with a map that fills in form data when a selection is made, but it is all on one page.  I like the pop-up idea.  Can't seem to understand how they did it?

Anyone have experience with this?

Thanks,

Greg