function hauptmenue() {

var de = document.documentElement;
var myWidth = window.innerWidth || self.innerWidth || (de&&de.clientWidth) || document.body.clientWidth;

if (!window.Weite) {
  window.onresize = neuAufbau;
  Weite = Fensterweite();
}

var minEbene3 = Weite-340;
var minEbene4 = Weite-510;

var navItems = document.getElementById("hauptmenu").getElementsByTagName("li");

var i,j,k,l,m,x,y;

for (i=0; i<navItems.length; i++) {
   if (navItems[i].className == "ebene1") {
      rechterbutton = document.getElementById(navItems[i].id);
      koord = getOffset(rechterbutton);     
      x = koord.X;
      y = koord.Y;
      navItems2 = document.getElementById(navItems[i].id).getElementsByTagName("li");
      for (j=0; j<navItems2.length; j++) {
         if (navItems2[j].className == "ebene1") {
            navItems3 = document.getElementById(navItems2[j].id).getElementsByTagName("li");
            for (k=0; k<navItems3.length; k++) {
               if (navItems3[k].className == "ebene1") {
                  if (x > minEbene3) {
                     window.document.getElementById(navItems3[k].id).style.left = "-340px";
                  }
                  navItems4 = document.getElementById(navItems3[k].id).getElementsByTagName("li");
                  for (l=0; l<navItems4.length; l++) {
                     if (navItems4[l].className == "ebene1") {
                        if (x > minEbene4) {
                           window.document.getElementById(navItems4[l].id).style.left = "-510px";
                           // übergeordnete auch auf links setzen
                           for (m=0; m<navItems3.length; m++) {
                              if (navItems3[m].className == "ebene1") {
                                 window.document.getElementById(navItems3[m].id).style.left = "-340px";
                              }
                           }
                        }
                     }
                  }
               }
            }
         }
      }   
   }
}
}


function getOffset(obj) {
   var ret = new Object();
   ret.X = 0;
   ret.Y = 0;
   while (obj.offsetParent) {
      ret.X = ret.X + obj.offsetLeft;
      ret.Y = ret.Y + obj.offsetTop;
      obj = obj.offsetParent;
   }
   return ret;
}

function neuAufbau () {
  if (Weite != Fensterweite())
    location.href = location.href;
}

function Fensterweite () {
  if (window.innerWidth) {
    return window.innerWidth;
  } else if (document.body && document.body.offsetWidth) {
    return document.body.offsetWidth;
  } else {
    return 0;
  }
}