FrameActions

This text element specifies ActionScript to be executed after all other frame commands have been executed but before the frame is displayed. FrameActions are executed when the frame is entered from another frame (unlike the enterFrame MovieClip event which triggers every frame regardless whether the frame head moves or not) so for single-frame timelines the actions are executed just once. All ActionScript except event handlers can be used here. ActionScript functions should not be referenced before they are defined however once defined they are accessible from any frame.
By default the script is expected as element content however the use of the optional 'src' attribute permits an external script to be identified using a URL. If this is specified then all element content is ignored.

Consult documentation on ActionScript for more information on scripting.