前端生成guid

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