document.onmousemove = mouseMove;

var mousePos = null;

function mouseMove(ev){
	ev = ev || window.event;
	mousePos = mouseCoords(ev);
	
	var leftPosition = mousePos.x + 10;
	var topPosition = mousePos.y - 120;
	
	document.getElementById('prevcont').style.left = leftPosition+"px";
	document.getElementById('prevcont').style.top = topPosition+"px";
}

function mouseCoords(ev){
	if(ev.pageX || ev.pageY){
		return {x:ev.pageX, y:ev.pageY};
	}
	
	return {x:ev.clientX + (document.documentElement ? document.documentElement.scrollLeft : document.body.scrollLeft), y:ev.clientY + (document.documentElement ? document.documentElement.scrollTop : document.body.scrollTop)};
}