var Guid={NewGuid: function () {

                var guid = (this._G() + this._G() +"-"+ this._G() +"-"+ this._G() +"-"+ this._G() +"-"+ this._G() + this._G() + this._G()).toUpperCase();

                return guid;

            },

            _G: function () {

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

            }

 };

console.log(Guid.NewGuid());

console.log(Guid.NewGuid());

console.log(Guid.NewGuid());

console.log(Guid.NewGuid());

// rfc4122 version 4

'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);

});