Events and properties of movie clip objects

When you use code to control a movie clip object, there are a number of built-in properties that can be changed:

._x The x position (0 = left)
._y The y position (0=top)
._width Width in pixels
._height Height in pixels
._alpha Valid values are 0 (fully transparent) to 100 (fully opaque). The default value is 100.
._visible Boolean value that indicates whether the movie clip is visible. Movie clips that are not visible ( _visible property set to false ) are disabled. For example, a button in a movie clip with _visible set to  false cannot be clicked
._rotation The rotation of the movie clip, in degrees, from its original orientation. Values from 0 to 180 represent clockwise rotation; values from 0 to -180 represent counterclockwise rotation.

Movie Clip events

onEnterFrame() the movie usually plays 12 frames per second, so this event happens 12 times per second to update the object.
onPress() The mouse is pressed down on the movie clip
onRelease() The mouse is released after clicking on the clip
onRollOver()

Invoked when the mouse pointer rolls over a movie clip.

onRollOut() Invoked when the pointer moves outside a movie clip area.

An example

// Dynamic class -- (saved in the file Dynamic.as)
// Any movie clip that uses this class will:
// each "tick" of the clock(onEnterFrame), the movie moves 1 pixel up and to the left
// each time you click moves the clip to the right and down 30 pixels
// each time the mouse is released the movie gets 5 pixels smaller in each direction
// each time the mouse rolls over the movie rotates 15 degrees to the left
// each time the mouse rolls away the movie becomes slightly more transparent
class Dynamic extends MovieClip { 
 function onEnterFrame() {
   this._y -=1;
   this._x -=1;
   }
 function onPress() { 
   this._x += 30; 
   this._y += 30;} 
 function onRelease(){
   this._width-=5;
   this._height-=5;
   }
 function onRollOver() {
   this._rotation -=15;
   }
 function onRollOut() {
   this._alpha-=2;
   }
}