Script doesn't work in Flash player 7

programming flash
1

Hi All,

Does anybody know why this script won’t work in Flash Player 7?

frame 1:
[AS]
spring = .5;
speed = 2;
MovieClip.prototype.bounce = function(targetY){
diff = targetY - this._y;
growth += diff*speed;
growth *= spring;
this._y += growth;
}
[/AS]
on the “circle” mc:
[AS]
onClipEvent(enterFrame){
bounce(targetY);
}
on(release){
this.targetY = random(300);
}
[/AS]

Works fine in player 6.

Thanks for your time.