Flash MX - Bewegungstween

MovieClip.prototype.mcRollOver = function() {
 this.onEnterFrame = function() {
 this._currentframe == this._totalframes ? delete this.onEnterFrame : this.nextFrame();
 };
};
MovieClip.prototype.mcRollOut = function() {
 this.onEnterFrame = function() {
 this._currentframe == 1 ? delete this.onEnterFrame : this.prevFrame();
 };
};
// usage 
button_mc.onRollOver = function() {
 this.mcRollOver();
};
button_mc.onRollOut = function() {
 this.mcRollOut();
};