function preloadButtons(path)
    {
      Button_0 = new Button('home', path, 'home1.gif', 'home2.gif');
      Button_1 = new Button('freizeit', path, 'freizeit1.gif', 'freizeit2.gif');
      Button_2 = new Button('mieter', path, 'mieter1.gif', 'mieter2.gif');
      Button_3 = new Button('mietflaechen', path, 'mietflaechen1.gif', 'mietflaechen2.gif');
      Button_4 = new Button('centerinfo', path, 'centerinfo1.gif', 'centerinfo2.gif');
    }


    function Button(name, path, image1, image2)
    {
      //--- Konstruktor:

      this.name = name;
      this.image1 = image1;
      this.image2 = image2;

      //--- Konstruktor - Preload Bilder:

      this.img_1 = new Image(); this.img_1.src = path+'images/buttons/'+image1;
      this.img_2 = new Image(); this.img_2.src = path+'images/buttons/'+image2;

      //--- Members:

      this.change_Button = change_Button;

    }


    function change_Button(index)
    {

      var i, j;

      j = false;

      for (i = 0; i < window.document.images.length; i++)
        {
          if (this.name == window.document.images[i].name)
          {
             j = true;
             break;
          }
        }

      if (j == true)
      {
        switch (index)
        {
          case 1: window.document.images[i].src = this.img_1.src;
                  break;
          case 2: window.document.images[i].src = this.img_2.src;
                  break;
          default: break;

        }
      }

    }