Dynamic Menu/List -Dreamweaver/Spry

Can somebody please point me in the direction of a good tutorial on how to create a dynamic menu in Dreamweaver with JavaScript and/or Spry?

I am trying to create a form where the available options depend on what value the user selects from a list/menu.

For example, if my drop down list/menu has the values ‘car’ ‘plane’ or ‘train’ and the user selected ‘train’ – the options in the next menu/list change to only allow the user to select values that I assign for ‘train’…

Thanks in advance for your help.