使用Java的倒数计时器

Question

I m working on online examination i just wnat to start timer at exam start and want to end as exam finish i hv endtime on my cotroller and im passing that endtime on view i want to start timer between system time and end time

Controller

public ActionResult TestStarted(int TestId,DateTime End_Time)
        {
            ViewBag.ct = 0;
            ViewBag.TestId = TestId;

            EAssessmentNew.BAL.StudentBal studBal = new EAssessmentNew.BAL.StudentBal();
            EAssessmentNew.Dal.Student_Answer_Master _studAnsdal = new       EAssessmentNew.Dal.Student_Answer_Master();


            ViewBag.EndTime = End_Time;
        }

View

<script type="text/javascript">





    var days, hours, minutes, seconds;


    var countdown = document.getElementById("lblCtime");


setInterval(function () {


    var current_date = new Date().getTime();
    var seconds_left = ( @ViewBag.EndTime - current_date) / 1000;


    days = parseInt(seconds_left / 86400);
    seconds_left = seconds_left % 86400;

    hours = parseInt(seconds_left / 3600);
    seconds_left = seconds_left % 3600;

    minutes = parseInt(seconds_left / 60);
    seconds = parseInt(seconds_left % 60);


    countdown.innerHTML = days + "d, " + hours + "h, "
    + minutes + "m, " + seconds + "s";  

}, 1000);
</script>

Suppose i have EndTime 1:00 PM and System Time 12:00 PM how can i start timer betwwen these two times as i want to convert my EndTime 1:00 PM into milliseconds as current date in my script returns me time in milliseconds.

Answer 1

What you need to do is whenever the user click on the Give Exam add the time to the Duration of exam that you are going to give him (ie Exam Start Time 1PM and you are giving user to 1 Hour of Time to Complete the Exam then you need to pass the date with the time 1PM + 1 HOUR More so it will count from that datetime to finish the exam) and pass this as End date with this function

<script>
    var end = new Date('08/14/2014 12:00 PM');

        var _second = 1000;
        var _minute = _second * 60;
        var _hour = _minute * 60;
        var _day = _hour * 24;
        var timer;

        function showRemaining() {
            var now = new Date();
            var distance = end - now;
            if (distance < 0) {

                clearInterval(timer);
                document.getElementById('countdown').innerHTML = 'EXPIRED!';

                return;
            }
            var days = Math.floor(distance / _day);
            var hours = Math.floor((distance % _day) / _hour);
            var minutes = Math.floor((distance % _hour) / _minute);
            var seconds = Math.floor((distance % _minute) / _second);

            document.getElementById('countdown').innerHTML = days + 'days ';
            document.getElementById('countdown').innerHTML += hours + 'hrs ';
            document.getElementById('countdown').innerHTML += minutes + 'mins ';
            document.getElementById('countdown').innerHTML += seconds + 'secs';
        }

        timer = setInterval(showRemaining, 1000);
</script>

The end date will automatically count based on the server datetime and you need not to worry about the local time.

DEMO1

DEMO2