The key differences between ActionScript 2 (AS 2) and ActionScript 3 (AS 3)

AS 3 is a much richer framework (more underlying functionality) than AS 2. ActionScript development is a part of both Adobe Flash Professional and Adobe Flex Builder. AS 2 is a nearly deprecated software development language..

Flash Professional provides animation conversion to ActionScript code.Flash Professional CS 3 and CS 4 both use the ActionScript 3. Flash Professional CS 2 and prior used ActionScript 2.

Flex Builder has uses ActionScript 3 code, since its initial product release, which it complies into a Rich Internet Application (RIA) client or Adobe AIR standalone application