Create action script for Breezing forms in Joomla

Need to write custom Action script in Breezing Forms for joomla that get values from database and display it in drop list. this drop list needs to be filtered according to previous selection in droplist. Here is detail. First list is continents second list is countries database comprise of two columns continent and country if some one selects Europe continent in first select list second select list get values from DB table where continent is Europe. If you need more details do not hesitate to contact. Good luck.