This javascript code will allow you to display the date of the page's last modification:

<script language="javascript">

date=document.lastModified
day=date.charAt(3)+date.charAt(4)
month=date.charAt(0)+date.charAt(1)
year=date.charAt(6)+date.charAt(7)+date.charAt(8)+date.charAt(9)
document.write("Last modification made on : "+day+"/"+month+"/"+year)

</script>