transition tween alpha

[hansolo]

i have tried to use the transition tween. Make the box opauqe to transparent. The only thing occurs is the trace command of the button click.
The box has no change. I cant see where the error is in my code.


btn.onPress = function(){
var tweenMc:Tween = new Tween(box,alpha,Strong.easeOut ,20,100,5,true);
trace("click")
}

[hansolo]

btn.onPress = function(){
var tweenMc:Tween = new Tween(box,"_alpha",Strong.easeOut ,20,100,5,true);
trace("click")
}

The problem was an error in my code.Incorrect syntax. The property for alpha needed quotes around and an underscore. "_alpha"

Thanks guys