Asp.Net Online Test with Timer

We got a requirement that, we need to implement logic for a timer which continues to run between page post backs. For each question the page sends a postback request to the server.

So to implement this logic, I used java script Timer with some custom functionality to maintain the clock time between the server round trips. Below is the code.

<div id="timer" style="height:30px; float:right; padding:3px" >

Time:<asp:Label ID="lblTimer" runat="server" ></asp:Label>

<asp:TextBox style="display:none" ID="tbTimer" runat="server"></asp:TextBox>

<asp:Button ID="hdnBtnTimeOut" OnClick="ExamTimeOut" runat="server" style="display:none" />

</div>

<script type="text/javascript" language="javascript">

var Timer;

var TotalSeconds;

function CreateTimer(TimerID, Time) {

        Timer = document.getElementById(TimerID);

        TotalSeconds = Time;

       

        UpdateTimer()

        window.setTimeout("Tick()", 1000);

}

function Tick() {

        if (TotalSeconds <= 0) {

            alert("Time's up!")

            document.getElementById('<%=hdnBtnTimeOut.ClientID %>').click();

                return;

        }

        TotalSeconds -= 1;

        UpdateTimer();

        window.setTimeout("Tick()", 1000);

}

function UpdateTimer() {

        var Seconds = TotalSeconds;

       

        var Days = Math.floor(Seconds / 86400);

        Seconds -= Days * 86400;

        var Hours = Math.floor(Seconds / 3600);

        Seconds -= Hours * (3600);

        var Minutes = Math.floor(Seconds / 60);

        Seconds -= Minutes * (60);

        var TimeStr = ((Days > 0) ? Days + " days " : "") + LeadingZero(Hours) + ":" + LeadingZero(Minutes) + ":" + LeadingZero(Seconds)

        Timer.innerHTML = TimeStr;

        document.getElementById('<%=tbTimer.ClientID %>').value = TimeStr;

}

function LeadingZero(Time) {

        return (Time < 10) ? "0" + Time : + Time;

}

</script>

C#

        private void SetTimer()

        {

            string time = tbTimer.Text;

            int totalSeconds = 0;

            if (!string.IsNullOrEmpty(time))

            {

                string[] timeParts = time.Split(':');

                string hours = timeParts[0];

                string minutes = timeParts[1];

                string secons = timeParts[2];

                int hoursCnt, minutesCnt, seconsCnt;

                Int32.TryParse(hours, out hoursCnt);

                Int32.TryParse(minutes, out minutesCnt);

                Int32.TryParse(secons, out seconsCnt);

                totalSeconds = hoursCnt * 60 * 60 + minutesCnt * 60 + seconsCnt;

                if (totalSeconds == 0)

                {

                    //Time up, Write you logic here,like exam report.

                    return;

                }

            }

            ScriptManager.RegisterStartupScript(this, this.GetType(), "startTimer", "CreateTimer('" + lblTimer.ClientID + "'," + totalSeconds + ");", true);

        }

//User clicks on this button ,to start the test.

protected void btnproceed_Click(object sender, EventArgs e)

        {

//Write ur logic , below EXAM_TIME is a constant variable.

            ScriptManager.RegisterStartupScript(this, this.GetType(), "startTimer", "CreateTimer('" + lblTimer.ClientID + "'," + EXAM_TIME + ");", true);

}

//User clicks on the “Next” button.

protected void btnnext_Click(object sender, EventArgs e)

        {

SetTimer();

}

protected void ExamTimeOut(object sender, EventArgs e)

        {

            SetTimer();

        }