var ns4up = (document.layers) ? 1 : 0;  
var ns6up = (document.getElementById && !document.all && !window.opera) ? 1 : 0;
var ie4up = (document.all && !window.opera) ? 1 : 0;
var op5up = (document.getElementById && window.opera) ? 1 : 0;

function ekZoom(a) {
 l='<center><img name="popuppic" src="'+a+'" onload="zeige_popup()" onmousedown="hide_popup()" style="filter:Alpha(opacity=100, finishopacity=100, style=0)"></center>'
 if (ie4up) {
  if (document.all.popuper.style.visibility=="visible") {hide_popup_schnell();}
  popuper.innerHTML=l;
 }
 if (ns6up) {
  if (document.getElementById("popuper").style.visibility=="visible") {hide_popup_schnell();}
  document.getElementById("popuper").innerHTML=l;
 }
 if (op5up) {
  if (document.getElementById("popuper").style.visibility=="visible") {hide_popup_schnell();}
  document.getElementById("popuper").innerHTML=l;
 }
}

function zeige_popup() {
 if (ie4up || ns6up || op5up) {
  breite=document.popuppic.width;
  hoehe=document.popuppic.height;
 }
 posx=(800-breite)/2;
 posy=(500-hoehe)/2;

 if (posx<0) {posx=0;}
 if (posy<0) {posy=0;}
 if (ie4up) {
  document.getElementById("popuper").style.pixelTop = posy+document.body.scrollTop;
  document.getElementById("popuper").style.pixelLeft = posx+document.body.scrollLeft;
  document.getElementById("popuper").filters.blendTrans.Apply();
  document.getElementById("popuper").style.visibility = "visible";
  document.getElementById("popuper").filters.blendTrans.Play();
 }
 if (ns6up) {
  document.getElementById("popuper").style.top = posy+pageYOffset;
  document.getElementById("popuper").style.left = posx+pageXOffset;
  document.getElementById("popuper").style.width = breite+2;
  document.getElementById("popuper").style.visibility = "visible";
 }
 if (op5up) {
  document.getElementById("popuper").style.pixelTop = posy+document.body.scrollTop;
  document.getElementById("popuper").style.pixelLeft = posx+document.body.scrollLeft;
  document.getElementById("popuper").style.visibility = "visible";
  document.getElementById("popuper").style.width = breite+2;
 }
}

function hide_popup() {
 if (ie4up) {
  document.getElementById("popuper").filters.blendTrans.Apply();
  document.getElementById("popuper").style.visibility = "hidden";
  document.getElementById("popuper").filters.blendTrans.Play();
 }
 if (ns6up) {
  document.getElementById("popuper").style.visibility = "hidden";
  document.getElementById("popuper").style.top = 0;
  document.getElementById("popuper").style.left = 0;
 }
 if (op5up) {
  document.getElementById("popuper").style.visibility = "hidden";
  document.getElementById("popuper").style.pixelTop = posy;
  document.getElementById("popuper").style.pixelLeft = posx;
 }
}

function hide_popup_schnell() {
 if (ie4up) {
  document.getElementById("popuper").style.visibility = "hidden";
  document.getElementById("popuper").style.pixelTop = 0;
  document.getElementById("popuper").style.pixelLeft = 0;
 }
 if (ns6up) {
  document.getElementById("popuper").style.visibility = "hidden";
  document.getElementById("popuper").style.top = 0;
  document.getElementById("popuper").style.left = 0;
 }
 if (op5up) {
  document.getElementById("popuper").style.visibility = "hidden";
  document.getElementById("popuper").style.pixelTop = posy;
  document.getElementById("popuper").style.pixelLeft = posx;
 }
}