function newImage(arg) {
  if (document.images) {
    rslt = new Image();
    rslt.src = arg;
    return rslt;
  }
}

function changeImages() {
  if (document.images && (preloadFlag == true)) {
    for (var i=0; i<changeImages.arguments.length; i+=2) {
      document[changeImages.arguments[i]].src = changeImages.arguments[i+1];
    }
  }
}

var preloadFlag = false;
function preloadImages() {
  if (document.images) {
    arr_down = newImage("http://www.u-w-f.de/images/global/arr_down.gif");
    bg_over = newImage("http://www.u-w-f.de/images/global/bg_nav_hover.gif");
    button_pdf_AT = newImage("http://www.u-w-f.de/images/service/button-pdf-AT-2.jpg");
    preloadFlag = true;
  }
}

function showHideLayer(xy,myimage)
{
  if (document.getElementById(xy).style.visibility == "visible")
  {
    document.getElementById(xy).style.visibility = "hidden";
    document.getElementById(xy).style.display = "none";
    document.getElementById(xy).style.height = "0px";
    document.getElementById(myimage).src = "http://www.u-w-f.de/images/global/arr.gif";
    return;
  }
  if (document.getElementById(xy).style.visibility == "hidden")
  {
    document.getElementById(xy).style.visibility = "visible";
    document.getElementById(xy).style.display = "block";
    document.getElementById(xy).style.height = "auto";
    document.getElementById(myimage).src = "http://www.u-w-f.de/images/global/arr_down.gif";
    return;
  }
}