User Guide

558 Chapter 7: ActionScript for Flash
MovieClip._alpha
Availability
Flash Player 4.
Usage
my_mc._alpha:Number
Description
Property; the alpha transparency value of the movie clip specified by my_mc. Valid values are 0
(fully transparent) to 100 (fully opaque). The default value is 100. Objects in a movie clip with
_alpha set to 0 are active, even though they are invisible. For example, you can still click a button
in a movie clip whose
_alpha property is set to 0. To disable the button completely, you can set
the movie clip's
_visible property to false.
You can extend the methods and event handlers of the MovieClip class by creating a subclass.
Example
The following code sets the _alpha property of a dynamically created movie clip named
holder_mc to 50% when the mouse rolls over the movie clip. Add the following ActionScript to
your FLA or AS file:
this.createEmptyMovieClip("holder_mc", this.getNextHighestDepth());
holder_mc.createEmptyMovieClip("image_mc", holder_mc.getNextHighestDepth());
MovieClip.onLoad
Invoked when the movie clip is instantiated and appears in
the Timeline.
MovieClip.onMouseDown
Invoked when the left mouse button is pressed.
MovieClip.onMouseMove
Invoked every time the mouse is moved.
MovieClip.onMouseUp
Invoked when the left mouse button is released.
MovieClip.onPress
Invoked when the mouse is pressed while the pointer is over
a movie clip.
MovieClip.onRelease
Invoked when the mouse is released while the pointer is over
a movie clip.
MovieClip.onReleaseOutside
Invoked when the mouse is clicked over a movie clip and
released while the pointer is outside the movie clip’s area.
MovieClip.onRollOut
Invoked when the pointer rolls outside of a movie clip area.
MovieClip.onRollOver
Invoked when the mouse pointer rolls over a movie clip.
MovieClip.onSetFocus
Invoked when a movie clip has input focus and a key is
released.
MovieClip.onUnload
Invoked in the first frame after the movie clip is removed from
the Timeline. The actions associated with the Unload movie
clip event are processed before any actions are attached to
the affected frame.
Event handler Description