I need to make a form that has 2 dropdown menu that have different dropdown list for each of the previous list

Question

ex. On Autotrader.com, when you search for a car, you chooose the the make, and depending on what make you chooose will display another list of items.

Answer 1

http://javascript.internet.com/forms/category-selection.html
http://javascript.internet.com/forms/category-form-script.html
http://javascript.internet.com/forms/country-state-drop-down.html (just modify the values)
http://javascript.internet.com/forms/dropdown-box-population.html

Answer 2

Try http://www.dynamicdrive.com/dynamicindex1/combodescribe.htm

It's a good script made for this purpose and also FREE.