// Termin oeffnen
  function open_termin(id) {
    var close = document.getElementById("t_close_" + id);
    var open = document.getElementById("t_open_" + id);
    open.style.display = "block";
    close.style.display = "none";
  }

  // Termin schliessen
  function close_termin(id) {
    var close = document.getElementById("t_close_" + id);
    var open = document.getElementById("t_open_" + id);
    open.style.display = "none";
    close.style.display = "block";
  }