function showframe(url) {
    // Objekte holen
    page = document.getElementById('h3-page');
    frame = document.getElementById('h3-frame');
    iframe = document.getElementById('h3-frame-obj');
    // url setzen
    iframe.src = url;
    // einblenden
    page.style.display = "none";
    frame.style.display = "block";
  }