function KLasseAendern (test){ 
document.getElementById('content').className="nothing";
//document.getElementById('content_box_long').style.display="none";
document.getElementById('ausblenden').style.display="none";
document.getElementById('bilder_content').style.display="block"
  imageId = 'bilder_content';
  image = document.getElementById(imageId);
  document.getElementById('bilder_content').className=test;setOpacity(image, 20);
  image.style.display="block";
  fadeIn(imageId,20);
  
	/* deactivate active links */
	var x = document.getElementsByTagName('a');
	for (var i = 0; i < x.length; i++)
		{
			if (x[i].className == "active")
			{
			x[i].className = "weg";
			}
		}
}

function setOpacity(obj, opacity) {
  opacity = (opacity == 100)?99.999:opacity;
  
  // IE/Win
  obj.style.filter = "alpha(opacity:"+opacity+")";
  
  // Safari<1.2, Konqueror
  obj.style.KHTMLOpacity = opacity/100;
  
  // Older Mozilla and Firefox
  obj.style.MozOpacity = opacity/100;
  
  // Safari 1.2, newer Firefox and Mozilla, CSS3
  obj.style.opacity = opacity/100;
}

function fadeIn(objId,opacity) {
  if (document.getElementById) {
    obj = document.getElementById(objId);
    if (opacity <= 100) {
      setOpacity(obj, opacity);
      opacity += 20;
      window.setTimeout("fadeIn('"+objId+"',"+opacity+")", 100);
    }
  }
}