Timestamp UUID en JavaScript

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