function AppMenu() {
  var self = this;
  var _app_menu_selector;
  var _app_menu_mbreite;
  var _app_menu_url_prefix = "";
  var _app_menu_template;

  /*
   * die nachfolgenden Funktionen steuern das ein- und
   * ausblenden des menues
   */
  this.init = function (url_prefix, mdesc, mtpl, mselector, mbreite) {
    self._app_menu_selector = mselector;
    self._app_menu_mbreite = mbreite;
    /*document.querySelector( "#nav-toggle" ).addEventListener("click", function() {
      app_menu_toggle();
    });*/
    $(self._app_menu_selector).css("flex-basis", "0em");
    self._app_menu_url_prefix = url_prefix;
    $.get(mtpl, function(template) {
      self._app_menu_template = template;
      Mustache.parse(self._app_menu_template);   // optional, speeds up future uses
      var menuDiv = $("<div/>");
      $(menuDiv).addClass('app-menu-content');
      $(menuDiv).css('position', "relative");
      $(menuDiv).css('left', '-300px');
      $(menuDiv).css('right', '0px');
      $(self._app_menu_selector).append(menuDiv);

      self.app_menu_laden(mdesc);
    });
  };

  this.app_menu_do_toggle = function(elem) {
    /*document.querySelector( "#nav-toggle" ).classList.toggle( "active" );
    document.querySelector( "#nav-toggle" ).blur();*/
    self.toggle();
  };

  this.toggle = function() {
    /*document.querySelector( "#nav-toggle" ).classList.toggle( "active" );
    document.querySelector( "#nav-toggle" ).blur();*/
    var menuDiv = $(self._app_menu_selector);
    if($(menuDiv).hasClass('app-menu-open')) {
      $(menuDiv).removeClass('app-menu-open');
      $(menuDiv).css("flex-basis", "0em");
    } else {
      $(menuDiv).addClass('app-menu-open');
      $(menuDiv).css("flex-basis", self._app_menu_mbreite); // z.B. "16em"
    }
  };

  /*
   * ab hier Steuerung des Menueinhalts
   */


  /*
   * mdesc: der URL einer JSON-Datei mit einer Menuebeschreibung
   */
  this.app_menu_laden = function(mdesc, richtung) {
    $.ajax({
      url: self._app_menu_url_prefix + mdesc,
      type: "GET",
      dataType : "json"
    }).done(function( json ) {
      self.app_menu_bauen(json, richtung);
    });
  };

  this.app_menu_bauen = function(menuejs, richtung) {

    // Endposition des bestehenden Menues beim Wechsel herauf
    var linksEndeAlt = "500px";
    var rechtsEndeAlt = "600px";
    // Anfangsposition des neuen Menues beim Wechsel herauf
    var linksAnfangNeu = "-300px";
    var rechtsAnfangNeu = "-1px";
    // Endposition des neuen Menues beim Wechsel herauf
    var linksEndeNeu = "0px";
    var rechtsEndeNeu = "300px";

    if(richtung === 'herunter') {
      // Endposition des bestehenden Menues beim Wechsel herunter
      linksEndeAlt = "-300px";
      rechtsEndeAlt = "-1px";
      // Anfangsposition des neuen Menues beim Wechsel herunter
      linksAnfangNeu = "500px";
      rechtsAnfangNeu = "600px";
      // Endposition des neuen Menues beim Wechsel herunter
      linksEndeNeu = "0px";
      rechtsEndeNeu = "300px";
    }

    var menuDiv = $("<div/>");
    $(menuDiv).addClass('app-menu-content');

    $(menuDiv).css('position', "relative");
    $(menuDiv).css('left', linksAnfangNeu);
    $(menuDiv).css('right', rechtsAnfangNeu);
    $(menuDiv).html(Mustache.render(self._app_menu_template, menuejs));

    $('.app-menu-content').delay(100).animate(
      {left: linksEndeAlt },
      100,
      function() {
        $('.smenu').attr('onclick','').unbind('click');
        $('.bitem').attr('onclick','').unbind('click');
        $('.mitem').attr('onclick','').unbind('click');
        $(self._app_menu_selector).empty();

        $(self._app_menu_selector).append(menuDiv);
        $('.smenu').on('click', self.app_menu_klick_herunter);
        $('.bitem').on('click', self.app_menu_klick_herauf);
        $('.mitem').on('click', self.app_menu_ausfuehren);

        $('.app-menu-content').delay(100).animate({left: linksEndeNeu });
        $('.app-menu-content').animate({right: rechtsEndeNeu });
      }
    );
    $('.app-menu-content').animate({right: rechtsEndeAlt });
  };

  this.app_menu_klick_herunter = function() {
    self.app_menu_laden($(this).attr('data-verweis'), 'herunter');
  };

  this.app_menu_klick_herauf = function() {
    self.app_menu_laden($(this).attr('data-verweis'), 'herauf');
  };

  this.app_menu_ausfuehren = function() {
    var functionName = $(this).attr('data-verweis');
    eval(functionName + "(this)");
  };

}