function getActiveElement() {
   var active = document.getElementById("active")
   if (active) return active;
   else return false;
}

function getCurrentElement() {
   var active = document.getElementsByName("active")
   if (active) {
      var current = document.getElementsByName("active")[0];
      if (current) current = current.parentNode;
      if (current) return current;
      else return false;
   }
   return false;
}

function setVisible(element) {
   
   if (element) {
      var idAttribute = document.createAttribute("id");
      idAttribute.nodeValue = "active";
      element.setAttributeNode(idAttribute);
   }
}

function setHidden(element) {

   if (element) {
      element.removeAttribute("id");
   }
      
}

function displayHoverMenu(menu) {

  setHidden(getActiveElement());
  setVisible(menu);
}

function displayCurrentSubMenu() {

   setHidden(getActiveElement());
   setVisible(getCurrentElement());
}

function updateWMTT(e) {
  wmtt = document.getElementById("mieterangaben");
  if (wmtt != null) {
    x = (document.all) ? window.event.offsetX + 20 : e.pageX - document.getElementById('content').offsetLeft + 30;
    y = (document.all) ? window.event.offsetY + 20 : e.pageY - 250;
    wmtt.style.left = x + "px";
    wmtt.style.top   = y + "px";
  }
}

function showMieter(area, nummer) { 
  mieter = document.getElementById("mieter" + nummer);
  if (mieter) {
     mieter.style.cssText = "visibility:visible";

     mietername = document.getElementById("mieterangaben");
     if (area.id) {
       area.style.cssText = "";
       mietername.innerHTML = "<p><b>" + area.id + "<\/b><br \/>" + area.className + "<\/p>";
       mietername.style.cssText = "visibility:visible;border:1px dashed #CCCCCC;background-color:white;filter:Alpha(opacity=90);opacity:0.9;";
     } else {
       area.style.cssText = "cursor:default;"
     }
  }
}

function hideMieter(nummer) {
  mieter = document.getElementById("mieter" + nummer);
  if (mieter) {
     mieter.style.cssText = "visibility:hidden";
     mietername = document.getElementById("mieterangaben");
     mietername.innerHTML = "<p><\/p>";
     mietername.style.cssText = "visibility:hidden;";
  }
}

function showSelectmenu(selectmenu) {
  elements = selectmenu.childNodes;
  anzahl = elements.length - 1;
  for (var i = 1; i <= anzahl; i++) {
    elements[i].style.cssText = "display:block;";
  }
  linie = document.getElementsByTagName('hr')[0];
  linie.style.cssText = "visibility:visible";
}

function hideSelectmenu(selectmenu) {
  elements = selectmenu.childNodes;
  anzahl = elements.length - 1;
  for (var i = 1; i <= anzahl; i++) {
    elements[i].style.cssText = "";
  }
  linie = document.getElementsByTagName('hr')[0];
  linie.style.cssText = "";
}