ActionScript for Flash MX: The Definitive Guide, 2nd Edition By Colin Moock
Chapter 18. ActionScript Language Reference
MovieClip.play( ) Method
Flash 5
begin the sequential display of frames in a clip or movie
mc.play()
Description
The MovieClip.play( ) method is an alternative to the global play( ) function. Use the MovieClip method form to control remote movie clips or main movies specified by mc.
For general usage instructions, see the global play( ) function.
Example
// Begin playing clip named intro_mc intro_mc.play();