Getting a box to resize

programming flash
1

Hi. I want to be able to press down on the Mouse, then a box appears that i can resive depending on where the mouse is. Think any strategy game, where u press down and drag a box around some units.

Im having some trouble however, and i cant get it to resize.

Heres the code i have so far

var i;
_root.onMouseDown = function() {
	sel = attachMovie("sel", sel+i, i);
	startx = _xmouse;
	starty = _ymouse;
	sel._x = startx;
	sel._y = starty;
	x = startx - _xmouse
	sel._xscale = startx-_xmouse;
	i++;
};
_root.onMouseUp = function() {
	removeMovieClip(sel);
};

Thanks