var hnum = 1;

function nextHeader(hmax)
{
  var h1s = $el('hp'+hnum);
  h1s.style.visibility = 'hidden';
  hnum = (hnum == hmax) ? 1 : (hnum + 1);
  var h2s = $el('hp'+hnum);
  h2s.style.visibility = 'visible';
}