function changeDisplayStyle(id, value) {
	document.getElementById(id).style.display = value;
}

function showMenu( whichMenu, submenu ) {
  if (submenu) {
    changeDisplayStyle(whichMenu.parentNode.parentNode.id, "block");
  } else {
    changeDisplayStyle('sub_' + whichMenu.id, "block");
  }
	return false;
	}

function hideMenu( whichMenu, submenu ) {
  if (submenu) {
    changeDisplayStyle(whichMenu.parentNode.parentNode.id, "none");
  } else {
    changeDisplayStyle('sub_' + whichMenu.id, "none");
  }
	return false;
}