Making dynamic Drop down menus

i was wondering if anyone knew how to make dynamic drop down menus for example:

you have 2 drop down menus next to eachother.

the one on the left is the category one and the one on the right is the sub category ones

in the category one there are 3 things...

when someoen selects (lets say) hardware
the menu on the right has a list of different types of hardware i.e cpus, motherboards, graphics cards etc.....

however, when smoene selects peripherals on the left menu,

the right menu dispplays a list of different peripherals i.e keyboards, mice, mouse mats etc.....

i know it's javascrript as someone tld me i just can't find anything on how to do it....

thx in advance

This is the wrong forum for javascript, but check out http://javascript.internet.com in the forms section. There are several scripts that will do what you want.

thanks - i found one, it just looks like a bit of a bitch to customise