function isDOM() {
 var isD = (document.getElementById ? true : false);
 return isD;
}
function isIE4() {
 var isI = ((document.all && !isDOM) ? true : false);
 return isI;
}
function isNS4() {
  var isN = (document.layers ? true : false);   //alle 4er-NetscapeVersionen; Netscape 4.08 kennt nur layer
  return isN;
}
function isNS6() {
  var isN = (navigator.userAgent.indexOf("Netscape6")!=-1 ? true : false);
  return isN;
}
function is_ie() {
  var is_i   = (agt.indexOf("msie") != -1);
  return is_i;
}

function changeImage(layerId, imgId, newStatus) {

 if(isDOM() || isIE4())  { //egal, ob img innerhalb eines layers ist oder nicht
  img1 = new Image();
  if(newStatus=='act') {
   img1.src = document.images[imgId].src.replace(/pas/,"act");
  }
  else if(newStatus=='pas') {
   img1.src = document.images[imgId].src.replace(/act/,"pas");
  }
  document.images[imgId].src = img1.src;
 }
 else if(isNS4())  {  //Netscape4
  img1 = new Image();

  if(layerId!='')  { //falls img innerhalb eines Layers
   if(newStatus=='act') {
    img1.src = document.layers[layerId].document.images[imgId].src.replace(/pas/,"act");
   }
   else if(newStatus=='pas') {
    img1.src = document.layers[layerId].document.images[imgId].src.replace(/act/,"pas");
   }
   document.layers[layerId].document.images[imgId].src = img1.src;
  }
  else { // falls img nicht innerhalb eines layers
   if(newStatus=='act') {
    img1.src = document.images[imgId].src.replace(/pas/,"act");
   }
   else if(newStatus=='pas') {
    img1.src = document.images[imgId].src.replace(/act/,"pas");
   }
   document.images[imgId].src = img1.src;
  }
 }
}
   
//changeColor(id, newColor);
//id = id des elements, dessen Farbe geaendert werden soll
//newColor = neue Farbe
//newWeight = neue Weight
function changeColor(id, newColor, newWeight) {
 if(id.substring(0,2)=="td") { //td-bgColor aendern
  if(isDOM()) {
    document.getElementById(id).style.backgroundColor = newColor;
   }
   else if(is_ie() && !isDOM()) {
    document.all[id].style.backgroundColor = newColor;
   }
   else if(isNS4()) {
   }
 }
 else {
   if(isDOM()) {
    document.getElementById(id).style.color = newColor;
   }
   else if(is_ie() && !isDOM()) {
    document.all[id].style.color = newColor;
   }
   else if(isNS4()) {
   }
 }
}