Fade prototype

1

I’m looking for a prototype for setting mc’s to fade in or out but I’m stuck with the code…here’s what I have so far

MovieClip.prototype.fadeIn = function fadeIn() {
mc.onEnterFrame=function() {
mc._alpha+= (targetAlpha-mc._alpha)/ease;
}
}

MovieClip.prototype.fadeOut = function fadeOut() {
mc.onEnterFrame=function() {
mc._alpha-= (targetAlpha-mc._alpha)/ease;
}
}

so far I cant get it to work…any ideas ?