// Elemente ein- oder ausblenden

function toggleDisplay(id) {
  el = document.getElementById(id);
  var display = el.style.display ? '' : 'none';
  el.style.display = display; 
}

// Popup-Fenster

function open_function(url,width,height,options) {
  self.msgWindow = open(url, "Window", "width=" + width + ",height=" + height
    + ",screenX=" + (screen.width-width)/2
    + ",screenY=" + (screen.height-height)/2
    + ",dependent=yes"
    + ",left=" + (screen.width-width)/2
    + ",top=" + (screen.height-height)/2
    + options
    );
  if (self.msgWindow) {
     self.msgWindow.focus();
    if (self.msgWindow.opener == null) self.msgWindow.opener = self;
  }
}