this.onMouseDown = function() {
	pressed = true;
	box._x = _xmouse;
	box._y = _ymouse;
	box._width = box._height=0;
	startXPos = _xmouse;
	startYPos = _ymouse;
};
this.onMouseMove = function() {
	if (pressed) {
		breite = _xmouse-startXPos;
		hoehe = _ymouse-startYPos;
		box._width = breite;
		box._height = hoehe;
	}
};
this.onMouseUp = function() {
	pressed = false;
};