ActionScript was initially designed for controlling simple 2D vector animations made in Adobe Flash (formerly Macromedia Flash). Initially focused on animation, early versions of Flash content offered few interactivity features and thus had very limited scripting capability. Later versions added functionality allowing for the creation of Web-based games and rich Internet applications with streaming media (such as video and audio).
Coming from a programming background my Flash applications and websites are created using Actionscript (AS3) and only very occasionally do I use the more traditional drawing/timeline approach. Working in this fashion allows for a greater degree of control and far more complex animations.