function initMenu() {
 var menuitems;
 menuitems = document.getElementsByTagName('LI');
 for(i = 0; i < menuitems.length; i++) {
  menuitems[i].onclick = togglemenu;
  if(menuitems[i].id == menu_id) {
   menuitems[i].className = 'selected'; 
  }
  else {
   menuitems[i].className = '';
  }
 }
 themenuitem = document.getElementById(menu_id);
 themenuitem.togglemenu = togglemenu;
 themenuitem.togglemenu();
}

function togglemenu() {
 pagina_id = this.id;

 var menuitems;
 var uls;
 var ul;
 var current;
 
 menuitems = document.getElementsByTagName('LI');
 for(i = 0; i < menuitems.length; i++) {
  if(menuitems[i].id == pagina_id) {
   menuitems[i].className = 'selected'; 
  }
  else {
   menuitems[i].className = '';
  }
  submenu = menuitems[i].getElementsByTagName('UL');
  for (j = 0; j < submenu.length; j++) {
   submenu[j].className='hidden';
  }
 }
 uls = this.getElementsByTagName('UL');
 for ( i = 0; i < uls.length; i++ ) {
  ul = uls[i];
  current = ul.className;
  ul.className = (
   current == 'hidden' ?
    'show' :
    'hidden' );
 }
}