var vrHeight = 685;
  var vrWidth = 1000;
  var vrLeft = ((screen.availWidth - vrWidth)/2);
  var vrTop = ((screen.availHeight - vrHeight)/2);
 
  function startVR(vrHeight, vrWidth, vrTop, vrLeft)
     {
         window.open('http://www.luesnerhof.it/cms/360/dswmedia/vr_menu1.html', 'Naturhotel_Luesnerhof', 'width=' + vrWidth + ',height=' + vrHeight + ',top=' + vrTop + ',left=' + vrLeft + ',menubar=no,resizable=no, scrollbars=no, toolbar=no');
     }