function showonlyone(thechosenone) {
      var submenu = document.getElementsByTagName("ul");
            for(var x=0; x<submenu.length; x++) {
                  name = submenu[x].getAttribute("name");
                  if (name == 'submenu') {
                        if (submenu[x].id == thechosenone) {
                        submenu[x].style.display = 'block';
                  }
                  else {
                        submenu[x].style.display = 'none';
                  }
            }
      }
}