var lastId = null;
function toggleVisibility(id) { 
  if (lastId != null && id == lastId) lastId = null;
  else {
	  if (lastId != null) Effect.toggle(lastId, 'slide');
	  lastId = id;
  }
  Effect.toggle(id, 'slide'); 
}

/*Event.observe(window, 'load', function() { 
  $('toggle-switch').observe('click', toggleVisibility); 
});*/