var XPosition = 20;
var YPosition = 20;
var MouseOverGrafik;

Event.observe(
	window,
	'load',
	function() {
		MouseOverGrafik = $('MouseOverGrafikCSS');
		if(MouseOverGrafik){
  		Event.observe(
  			$$('body')[0], 
  			'mousemove',
  			function(e) {
  				x = Event.pointerX(e);
  				y = Event.pointerY(e);
  				MouseOverGrafik.style.visibility = 'visible';
  				MouseOverGrafik.style.left = x + XPosition + 'px';
  				MouseOverGrafik.style.top = y + YPosition + 'px';
          
        }
  		);
  	}
	}
);