/* Hide all submenus */
function hideSubMenus() {
  var i;
  for (i in subMenuIDs) {
    if (document.getElementById(subMenuIDs[i]) != undefined) {
      document.getElementById(subMenuIDs[i]).style.display = 'none';
    }
  }
}

/* Show one submenu */
function showSubMenu(subMenuID) {
  hideSubMenus();
  document.getElementById(subMenuID).style.display = 'block';
}