Hi,
You can create a javascript code
var fID = null;
var currentDate = new Date();
var currentYear = currentDate.getFullYear();
var currentMonth = currentDate.getMonth()+1;
var currentDay = currentDate.getDate();
var currentHours = currentDate.getHours();
var currentMinutes = currentDate.getMinutes();
var currentSeconds = currentDate.getSeconds();
fID = "ID" + currentYear + currentMonth + currentDay +
+ currentHours + currentMinutes + currentSeconds;
fID is uniquely identify each document.