Generate fake GUID(also known as UUID) by using javascript

guid.js

// original from http://guid.us/GUID/JavaScript

function S4() {
    return (((1+Math.random())*0x10000)|0).toString(16).substring(1); 
}

function generateGuid() {
    return (S4() + S4() + "-" + S4() + "-4" + S4().substr(0,3) + "-" + S4() + "-" + S4() + S4() + S4()).toLowerCase();
}

//original from http://www.broofa.com/Tools/Math.uuid.js RFC4122v4 solution

Math.uuid = function() {
    return 'xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx'.replace(/[xy]/g, function(c) {
        var r = Math.random()*16|0,
            v = c == 'x' ? r : (r&0x3|0x8);
        return v.toString(16);
    });
};