Hi efret welcome to the Monestary. Please have a look at Tutorials under the Welcome to the Monestary Heading. You need to use <code> tags around your code so we can read it. Also the probability of getting a good answer is roughly inversly proportional to the quantity of code you post - aka distill the question down to a very simple case. We don't have time to read hundreds of lines of irrelevant code.

Anyway. The answer you seek: It is more of a javascript problem. Here is good tutorial on exactly how you do it. Where the author uses php you can use perl (ie to deliver data from a DB to the second select list without having to refresh the page by using an iframe). As you can see the bulk of the work is done in js.

Fixed typo PodMaster