My web page has three data-driven combo boxes. The first always has the same options. The options in the second box depend upon the slection made in the first box. The options in the third box depend on the selection made in the second box. The contents of each combo box is built by querying a data table.
a) What is the technique for dynamically building the contents of the second and third boxes once the controlling selection has been made?
b) Can all three combo boxes reside on the same web page?
c) Or does page 1 hold combo box 1, page 2 combo box 2 and page 3 combo box 3?
d) If c) can the submit button direct the next page to be loaded into a different frame? If yes, how?
Phew! That's it for now!

You can extract the data for all 3 combo boxes into a client-side JavaScript array and then change the options for the 2nd and the 3rd combo boxes, when onChange event it's triggered in its parent combo box.

Check here

Perhaps this may hopefully give some ideas and it's got a downloadable sample:

ASP Design Tips - Dependent Listboxes
http://www.bullschmidt.com/devtip-de...tlistboxes.asp