cus_Menu.js

var acc = document.getElementsByClassName("accordion");
            var i; 
            for (i = 0; i < acc.length; i++) {
              acc[i].addEventListener("click", function() {
                this.classList.toggle("active");
                var subMenu = this.nextElementSibling;
                if (subMenu.style.maxHeight) {
                    subMenu.style.maxHeight = null;
                } else {
                    subMenu.style.maxHeight = subMenu.scrollHeight + "px";
                } 
              });
            }

function nordbahnview(){
  var viewp = vcs.vcm.Framework.getInstance().viewpoints.NordBView
  vcs.vcm.Framework.getInstance().getActiveMap().gotoViewPoint(viewp);
}

document.addEventListener('touchstart', function addtouchclass(e){ // first time user touches the screen
  var drop = document.getElementById("dropdownMain")
    drop.classList.add('can-touch') // add "can-touch" class to document root using classList API
    document.removeEventListener('touchstart', addtouchclass, false) // de-register touchstart event
}, false)

var dropD = document.getElementById("dropdownMain")
var dropC = document.getElementById("dropdownContent")
dropD.onclick = function(){
  if (dropD.className == "can-touch"){
    if (dropC.style.display === "none"){
      dropC.style.display = "block";
    } else if (dropC.style.display === "block"){
      dropC.style.display = "none";
    }
  }
}