Behaviours are predefined scripts that you can attach to objects in your FLA file. behaviours provide functionality such as frame navigation, loading external SWF and JPEG files, controlling the stacking order of movie clips, and movie clip dragging. behaviours also enable you to add features to a Flash project without writing ActionScript; dissecting behaviour code can help you learn how ActionScript works.

Behaviors are available only for ActionScript 2 and earlier. They are only available when you work in the Actions panel, not in an external script file. Typically, you select a triggering object in your document (such as a movie clip or button), select Add in the behaviours panel, and then select a behavior.