If you're familiar with traditional programming languages and you want to develop some rich Internet applications that take advantage of the power of Flash, you might want to take a look at Flex. Read on to learn how this presentation server can help.
Introduction to Flex - About ActionScript 2.0 in MXML applications (Page 3 of 5 )
ActionScript extends the capabilities of Flex application developers. With ActionScript, you can define event listeners and handlers, get or set component properties, handle call-back functions, and create new classes, packages, and components.
You can use ActionScript in your Flex applications in the following ways:
Insert ActionScript code blocks with the <mx:Script> tag. In these code blocks, you can add new functions, handle errors and events, and perform other tasks in your application or its supporting MXML files.
Call global ActionScript functions that are stored in the system_classes directory structure.
Reference external classes and packages in user_classes to handle more complex tasks. This lets you take advantage of ActionScript support for object-oriented programming concepts such as code reuse and inheritance.
Use standard Flex components. The logic of components and helper classes in the Flex application model is based on ActionScript classes.
Extend existing components with ActionScript classes.
Create new components in ActionScript.
Create new components in the Flash authoring environment (SWC files).
Flash 
/ 30 
ActionScript in Flex Applications
