if(window.document.all){}
else
{
 window.document.captureEvents(Event.MOUSEMOVE);
}
window.document.onmousemove = mtrack;
function mtrack(e)
{
 var x, y, x1, x2, y1, y2, dx=0, dy=0;
 fact = (breite_gross/breite_normal);
 opp  = 100;
 if(document.all)
 {
  x  = event.x - image_left;
  y  = event.y - 40;
  dx = window.document.body.scrollLeft;
  dy = window.document.body.scrollTop;
 }
 else
 {
  x = e.pageX-[image_left];
  y = e.pageY-40;
 }
 x1 = -opp + (x+dx) * fact; //left
 y1 = -opp + (y+dy) * fact; //top
 x2 = +opp + (x+dx) * fact; //right
 y2 = +opp + (y+dy) * fact; //bottom
 //window.document.images.bild_gross.style.left=(x+dx)*(1-fact);
 //window.document.images.bild_gross.style.top=(y+dy)*(1-fact);
 window.document.images.bild_gross.style.clip = "rect(" + y1 + "px," + x2 +"px," + y2 + "px," + x1 + "px)";
}