if (Date.parse(document.lastModified) != 0) {
  var modiDate = new Date(document.lastModified);
  var monthName = new Array("01", "02", "03", "04", "05", 
   "06", "07", "08", "09", "10", "11", "12");
  document.write("Last modified: " + modiDate.getFullYear() + "-" + monthName[modiDate.getMonth()] + "-" + modiDate.getDate());
  }