UUID / GUID in JavaScript

uuid-guid.js

// https://en.wikipedia.org/wiki/Universally_unique_identifier
// https://en.wikipedia.org/wiki/Globally_unique_identifier
// No hyphens (-) in below but can be add in the 'xxxxxxxxxxxx4xxxyxxxxxxxxxxxxxxx'

var uuid = 'xxxxxxxxxxxx4xxxyxxxxxxxxxxxxxxx'.replace(/[xy]/g, function(c) {
    var r = Math.random()*16|0, v = c == 'x' ? r : (r&0x3|0x8);
    return v.toString(16);
});

console.log(uuid);