function show_menu_tab(named) {
  $$('div#content_swap li').each(function(li) {
    if(li.id == named) {
      if(!Element.visible(li)) {
        new Effect.Appear(li, {duration: 0.6, queue:'end'});
      }
    } else {
      if(Element.visible(li)) {
        new Effect.Fade(li, {duration: 0.6, queue:'front'});
      }
    }
  });
  return false;
}