Getting started with ActionScript overview
Macromedia Flash MX 2004 and Flash MX Professional 2004 are the professional standard authoring tools for producing high-impact web experiences. ActionScript is the language you use when you want to develop an application within Flash. You don't have to use ActionScript to use Flash, but if you want to provide user interactivity, work with objects other than those built into Flash (such as buttons and movie clips), or otherwise turn a SWF file into a more robust user experience, you'll probably want to use ActionScript.