While this chapter is not intended to be the sole source of reference for developing in Actionscript 3.0, Flex, or Ajax, it is our hope that developers new to any of these languages will be able to use it to at least get up and running while working with many of the examples throughout this book.
ActionScript, the language used in Flash and Flex, has evolved significantly from its beginnings as a simple script used to animate vector graphics. ActionScript 3.0 is a fundamental evolution of the language that requires an entirely new virtual machine called ActionScript Virtual Machine 2, or AVM2. The latest Flash Player, Flash Player 9, is used for Flash and Flex and supports both the first virtual machine, AVM1, and the new ActionScript 3.0 virtual machine. ActionScript 3.0 provides a significant improvement in performance and a more mature programming model that is far better suited for rich Internet application development.
The following section details ...