function modifiedDate() {
   var millisecs = Date.parse(document.lastModified);
   if (millisecs != 0) {
     var moddt = new Date(millisecs);
     var month = moddt.getMonth() + 1;
     return getYear(moddt) + "-" + twoDigits(month) + "-" + twoDigits(moddt.getDate());
   } else {
      return "";
   }
}

function twoDigits(num) {
   return (num < 10) ? "0" + num : num;
}

// workaround for browsers that don't have a working getFullYear()
function getYear(theDate) {
	var year = theDate.getYear() % 100;
	year += (year < 38) ? 2000 : 1900;
	return year;
}