[support] Dynamically display parent/child taxonomy terms in a separate list?

Is there a way to display a single-hierarchy taxonomy terms separately? For example, if we have this list: Parent1 --child1 --child2 Parent2 --child3 --child4 --child5 I want to show two drop-down menus, populating the first one with: Parent1 Parent2 Once a selection is selected in this first drop-down menu, a second drop-down menu is populated with the children based on the selection of the first drop-down menu. What's the best way to do this? Thanks!