Dynamic dropdown menus

I'm just trying to do my first experiments with js, but I need some
good examples to start with..
I need to design a dynamic form with two dropdown menus picking their
select values from a db: my problem is, how can I make the selection
in the first menu affect the value list in the second, without using
any buttons? I mean, you just have to click on the first menu and
select the desired item, then the proper select list is "loaded" into
the second (which may be empty or even hidden before the first
selection)...

re: Dynamic dropdown menus

Here's a modular, customizable script for linked select boxes, from WebOnWebOff.com.

You can specify what options to display at the start, or options to display when no options exist for the selected value.

Linked select boxes

Hope this helps...