Spring effect on my tab menu : how?

1

hi,

for a multiple horizontal tab menu, i developpe a function
to move my tab up and down, when my cursor rollover it.

here my as code :

*function scrolling(nom, coord, coef) {
nom.onEnterFrame = function() {
this._y -= (coord+this._y)*coef;
if (this._y == coord) {
delete this.onEnterFrame;
}
};
}

*i want to add a cool spring effect, when my tab scroll up and scroll down…but how can i make this effect ?

Thanks.