var self = this;
                    var random = parseInt(Math.random() * Math.pow(2, 32));
                    var now = parseInt(new Date().getTime() / 1000);
                    var e = now + 60; //簽名過期時間為當前+60s
                    var path = '';//多次簽名這裡填空
                    var str = 'a=' + self.appid + '&k=' + sid + '&e=' + e + '&t=' + now + '&r=' + random +
                            '&f=' + path + '&b=' + self.bucket;
                    var sha1Res = CryptoJS.HmacSHA1(str, skey);//這裡使用CryptoJS計算sha1值，你也可以用其他開源庫或自己實現
                    var strWordArray = CryptoJS.enc.Utf8.parse(str);
                    var resWordArray = sha1Res.concat(strWordArray);
                    var res = resWordArray.toString(CryptoJS.enc.Base64);
                    setTimeout(function () {//setTimeout模擬一下網路延遲的情況
                        callback(encodeURIComponent(res));
                    }, 1000);