Updated JavaScript UUID Generator v.0.3

The JavaScript UUID Generator class has been refreshed again and is even more efficient than the 0.2 version due largely in part to heavier reliance on built in JavaScript functions. It’s still not a “REAL” UUID, but it’s good enough for most projects. The changes are as follows:

  • A leaner and more efficient returnBase(val, base) method for conversion to base16 strings. The original version from irt.org has been replaced with built in JavaScript methods. Some testing for your target platforms should be performed to ensure compatibility with your engine.
  • The change from randrange(min, max) in v.0.1 to rand(max) in 0.2 introduced a bug where the maximum value provided would never be matched. This has been fixed to correct for that issue.

Special thanks go out to Robert Kieffer for pointing out these issues and providing the updated code for the base 16 conversion.

Download the latest version.

uuid.js - Version 0.3
JavaScript Class to create a UUID like identifier

Copyright (C) 2006-2008, Erik Giberti (AF-Design), All rights reserved.

This program is free software; you can redistribute it and/or modify it under 
the terms of the GNU General Public License as published by the Free Software 
Foundation; either version 2 of the License, or (at your option) any later 

This program is distributed in the hope that it will be useful, but WITHOUT ANY 
WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A 
PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with 
this program; if not, write to the Free Software Foundation, Inc., 59 Temple 
Place, Suite 330, Boston, MA 02111-1307 USA

The latest version of this file can be downloaded from

6/5/06 	- Initial Release
5/22/08 - Updated code to run faster, removed randrange(min,max) in favor of
          a simpler rand(max) function. Reduced overhead by using getTime() 
          method of date class (suggestion by James Hall).
9/5/08	- Fixed a bug with rand(max) and additional efficiencies pointed out 
	  by Robert Kieffer http://broofa.com/

- Still no way to get MAC address in JavaScript
- Research into other versions of UUID show promising possibilities 
  (more research needed)
- Documentation needs improvement


// On creation of a UUID object, set it's initial value
function UUID(){
	this.id = this.createUUID();

// When asked what this Object is, lie and return it's value
UUID.prototype.valueOf = function(){ return this.id; }
UUID.prototype.toString = function(){ return this.id; }


UUID.prototype.createUUID = function(){
	// Loose interpretation of the specification DCE 1.1: Remote Procedure Call
	// described at http://www.opengroup.org/onlinepubs/009629399/apdxa.htm#tagtcjh_37
	// since JavaScript doesn't allow access to internal systems, the last 48 bits 
	// of the node section is made up using a series of random numbers (6 octets long).
	var dg = new Date(1582, 10, 15, 0, 0, 0, 0);
	var dc = new Date();
	var t = dc.getTime() - dg.getTime();
	var h = '-';
	var tl = UUID.getIntegerBits(t,0,31);
	var tm = UUID.getIntegerBits(t,32,47);
	var thv = UUID.getIntegerBits(t,48,59) + '1'; // version 1, security version is 2
	var csar = UUID.getIntegerBits(UUID.rand(4095),0,7);
	var csl = UUID.getIntegerBits(UUID.rand(4095),0,7);

	// since detection of anything about the machine/browser is far to buggy, 
	// include some more random numbers here
	// if NIC or an IP can be obtained reliably, that should be put in
	// here instead.
	var n = UUID.getIntegerBits(UUID.rand(8191),0,7) + 
			UUID.getIntegerBits(UUID.rand(8191),8,15) + 
			UUID.getIntegerBits(UUID.rand(8191),0,7) + 
			UUID.getIntegerBits(UUID.rand(8191),8,15) + 
			UUID.getIntegerBits(UUID.rand(8191),0,15); // this last number is two octets long
	return tl + h + tm + h + thv + h + csar + csl + h + n; 

// GENERAL METHODS (Not instance specific)

// Pull out only certain bits from a very large integer, used to get the time
// code information for the first part of a UUID. Will return zero's if there 
// aren't enough bits to shift where it needs to.
UUID.getIntegerBits = function(val,start,end){
	var base16 = UUID.returnBase(val,16);
	var quadArray = new Array();
	var quadString = '';
	var i = 0;
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3 Responses to Updated JavaScript UUID Generator v.0.3

  1. Anuj Khanna says:


    Is there a java version of this generator. I need to use this from a Java program in jdk 1.4

  2. Erik says:

    @Anuj Try looking up java.util.UUID

  3. Skeeve says:

    Clicking the download link gives me:


    You don’t have permission to access /services/javascript/uuid/uuid.js on this server.