function buchen() {
 MeinFenster =
 window.open("http://haus-alexandrine.de/tinc?key=nSrdXDrU", "Zweitfenster", "toolbar=no,width=640,height=500,directories=no,status=no,scrollbars=no,menubar=no,resizable=no,screenX=0,screenY=0");
 MeinFenster.focus();
}