function mover(id) {
	var top    = document.getElementById(id).style.top.replace(/px/gi, "");
	var height = document.getElementById(id).style.height.replace(/px/gi, "")
	top = parseInt(top);
	if(top <= -height) {
		top = (height);
	}

	top -= 1;

	document.getElementById(id).style.top = top;
}