ASP.NET RAZOR自动生成的js Timer

 <input type="hidden" value="@(Model.TimeLength)" id="examTimeLength" />
                    <input type="hidden" value="@ViewData["ExamId"]" id="_ControlerId" />
                    <span id="@ViewData["ExamId"]" class="fas_time"></span>
                    <a class="fas_submit" id="submitExam" href="#" style="display: none">我要交卷</a>

 function timer() {
        var time = $("#examTimeLength").val();
        var Timer = {
            controleId: $("#_ControlerId").val(),
            cookieName: $("#_ControlerId").val(),
            iTotalTime: null,
            timerId: null,
            init: function () {
                this.remainTime();
            },
            addZero: function (num) {
                var str = num < 10 ? Number(num) <= 0 ? '00' : '0' + num : num + '';
                return str;
            },
            remainTime: function () {
                var _this = this,
                    oSpan = document.getElementById(_this.controleId);
                _this.timerId = setInterval(function () {

                    _this.iTotalTime = time;
                    if (_this.iTotalTime <= 0) {
                        clearInterval(_this.timerId);
                        var functionName = "submitAnswer";
                        if (functionName) {
                            eval(functionName + "()");
                        }
                        return;
                    }

                    _this.iTotalTime--;
                    time--;
                    var hours = _this.addZero(Math.floor(_this.iTotalTime / 3600));
                    var minutes = _this.addZero(Math.floor((_this.iTotalTime - hours * 3600) / 60));

                    var secs = _this.addZero(Math.floor(_this.iTotalTime % 60));
                    var str = '{h}:{m}:{s}';

                    str = str.replace('{h}', hours);
                    str = str.replace('{m}', minutes);
                    str = str.replace('{s}', secs);

                    oSpan.innerHTML = str;
                }, 1000);
            }

        };
        Timer.init();
    }