Multiple Drop Downs

i guess it depends on the domain for that answer. If it's a box with hundreds of webpages serving thousands of customers you'd want to conserve network bandwidth you'd probably want to do javascript, but i wouldn't consider reloading a page a big hit since if you just open the connection and runing two queries. But if you need the bandwidth you could do it with javascript.

I try to keep things out of javascripts and out of the hands of the client. Mainly because if they're running an older computer it will take longer to load and put unnessary strain on them and also if the client has scripting disabled you have no more drop down boxes and your site is pretty much disabled. With the strickly asp method you'd have at least the options to choose from and not any core functionality taken from it. That's my 2 cents on javascript to asp.