var mouseY=0;
var mouseX=0;
var mid;

lo=new Image(); lo.src="images/lo.jpg";    // links oben
l=new Image(); l.src="images/l.jpg";       // links
lu=new Image(); lu.src="images/lu.jpg";    // links unten
u=new Image(); u.src="images/u.jpg";       // unten
ro=new Image(); ro.src="images/ro.jpg";    // rechts oben
r=new Image(); r.src="images/r.jpg";       // rechts
ru=new Image(); ru.src="images/ru.jpg";    // rechts unten


if(document.body)
  {
  if(document.body.clientWidth)
    mid=document.body.clientWidth / 2;
  else
    mid=window.innerWidth / 2;
  }
else
  mid=window.innerWidth / 2;

  
function Berechne()
 {
 mouseX -= mid;

 var pos=mouseY / mouseX;
 var winkel=Math.atan(pos) * 180 / Math.PI;


 if(winkel < 0)
   {
   if (winkel > -20)
     jpg="images/lo.jpg";
   else if (winkel > -60)
     jpg="images/l.jpg";
   else if (winkel > -80)
     jpg="images/lu.jpg";
   else
     jpg="images/u.jpg";
   }
 else
   {
   if (winkel < 20)
     jpg="images/ro.jpg";
   else if (winkel < 60)
     jpg="images/r.jpg";
   else if (winkel < 80)
     jpg="images/ru.jpg";
   else
     jpg="images/u.jpg";
   }
 document.images[0].src=jpg;

 window.status="Winkel: "+winkel;
 }
 
 if(window.captureEvents)
  {
  window.captureEvents(Event.MOUSEMOVE);
  window.onmousemove=MousePosNN;
  }

function MousePosNN(wo)
  {
  mouseY = wo.pageY;
  mouseX = wo.pageX;

  Berechne();
  }