Actionscript
Actionscript is the programming language used by Adobe Flash. Although you don't need to know Actionscript (or even have any programming experience) to create Flash files, Actionscript can greatly increase your creative possibilities.
Actionscript is quite similar to JavaScript, the well-known and hugely popular scripting language used in web design. If you are familiar with JavaScript you will find Actionscript very easy to learn.
See also: