Actionscripting is Flash's scripting language for adding interactivity to your movies.
You can use actionscripting to create navigation, games, e-commerce sites, etc.
Actionscript is based on JavaScript. There are similarities in the syntax of the languages. The syntax is called dot syntax.
Flash follows basic concepts in programming: variables, statements, loops, conditional statements, operators, functions, objects, methods, properties, and classes.
There are two main panels to program with in Flash (found under the Windows menu in the Development area)
The Actions Panel: Where you script by hand (MX still lets you have assistance, but 2004 doesn't) (more advanced)
The Behaviors Panel: Where you can select from predefined actions (for beginners)
You can also use the Movie Explorer (Windows>Other Panels) to view and find actionscript as well as other elements (bitmaps, symbols, sounds, text, etc.) in your movie file. This makes changing things much faster and more efficient.