Alpha on rollover

i’m trying to learn some AS. Now i made some simple code which should bring the alpha down step by step, en bring it back up when rolling outside.


on(rollOver){
	for(i=0; i <= 100; i++){
		this._alpha = this._alpha - 1;
	}
}

this is the part for alpha down as you can see, but i think this goes way to fast. how can i slow this progress down?