Random movement question

Hey i have this code i understand somewhat

MovieClip.prototype.moveMe = function(begin, end, speed) {
    if (this._x<=end) {
        this._x += speed;
    } else {
        this._x = begin;
        this._y = Math.random()*(64.5-0.5)+5;

and the movieClip

onClipEvent (load) {
	this._y = Math.random()*(64.5-0.5)-5;
	var begin1 = (0 - (this._width / 2))
	var end1 = (Stage.width + (this._width / 2))
	var speed1 = Math.round (((Math.random() * 4) + 1))
onClipEvent (enterFrame) {
	this.moveMe (begin1, end1, speed1)

this moves along the X axis at a random speed / y axis

now how do invert it to make it go random on the Y axis with the stage width being 445y , 0y and 441x, 750x man all this math/coding fries my brain!!

Well if its moving on the _x and having the _y random, then just switch the _x’s and the _y’s in the scripts.

That way the _y will be moving and the _x will be random.