Generate UUID using Simple JavaScript Function

uuid.js

var generateGuid = function () {
    function s4() {
        return Math.floor((1 + Math.random()) * 0x10000).toString(16).substring(1);
    }
    return s4() + s4() + '-' + s4() +
        '-' + s4() + '-' + s4() + '-' + s4() + s4() + s4();
};
console.log(generateGuid());