1.3. From ActionScript 2.0 to ActionScript 3.0

If you've programmed in ActionScript 2.0 before, ActionScript 3.0 has a whole lot of new features for you to explore. Here is an overview of the key new features. You may skip this section if you are coming to ActionScript 3.0 from a different language.

1.3.1. Display List

In ActionScript 2.0, there were three basic types of objects that could be displayed: movie clips, buttons, and text fields. These types didn't inherit from a common source, meaning polymorphism didn't work for these display types. Furthermore, instances of these display types always had a fixed, parent-child relationship with other instances. For example, to create a movie clip, you had to create that movie clip as a child of an existing movie clip. It was not possible to move a movie clip from one parent to another.