Hey how do I change this AS to work in 8?

It doesn’t work in 8 but will work in the previous versions. I already changed the var and added :Object to it cuz I know Flash 8 needs those now. but I still dont understand why and how to make this code compatible with 8.

[AS]function move(clipName) {
var slider:Object = this;
destination = slider.ynew;
position = clipName._y;
bounce = 0.800000;
speed = 5;
velocity = velocity * slider.bounce + (destination - position) / slider.speed;
clipName._y = clipName._y + velocity;
}
this.ynew = 20;
mainHeader_mc.onEnterFrame = function ()
{
move(this);
};
stop();[/AS]

Thanks guys! :krazy: