ActionScript is the scripting language of Macromedia Flash. a scripting language is a way to communicate with a program; you can use it to tell Flash what to do and to ask Flash what is happening as a movie runs.
ActionScript is an ECMAScript-based programming language used for controlling Macromedia Flash movies and applications. since both ActionScript and JavaScript are based on the same ECMAScript syntax, the client model is dramatically different: while JavaScript deals with windows, documents and forms, ActionScript deals with movie-clips, text fields and sounds.