function expand(id) {
  if(id == 0) return;
  else {
    if (document.getElementById("expand" + id).style.display == 'none') {
        document.getElementById("img" + id).src = "../../../../fileadmin/images/DLCenter/collapse.gif";
        document.getElementById("expand" + id).style.display = "";
    } else {
      document.getElementById("img" + id).src = "../../../../fileadmin/images/DLCenter/expand.gif";
      document.getElementById("expand" + id).style.display = "none";
    }
  }
}