function change_menu(div)
{
  var menu = div;
  var n_id = menu.getAttribute('id');

  menu.style.backgroundPosition = "0 0";
  menu.getElementsByTagName('h5')[0].style.display = 'block';
  menu.getElementsByTagName('ul')[0].style.display = 'block';

  if(n_id == 'rt_m') var div_id = 'lt_m'; else var div_id = 'rt_m';

  var o_menu = document.getElementById(div_id);

  o_menu.style.backgroundPosition = "0 -329px";
  o_menu.getElementsByTagName('h5')[0].style.display = 'none';
  o_menu.getElementsByTagName('ul')[0].style.display = 'none';
}