Adding a scale up code

programming flash
1

How would I write a function in this code to make it so that ‘target_mc’ will scale up once rolled over?

target_mc.onRollOver = function() {
this._alpha = 50;
thumbNailScroller();
};

or to scroll down once rolled out?

target_mc.onRollOut = function() {
this._alpha = 100;
};