javascript - how do I pause and resume a timer? - Stack Overflow

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I got this function that starts a timer on this format 00:00:00 whenever I click on a button. But I don't know how to do functions resume and pause. I've found some snippets that I thought could be helpful but I couldn't make those work. I'm new to using objects in js.

function clock() {
  var pauseObj = new Object();

  var totalSeconds = 0;
  var delay = setInterval(setTime, 1000);

  function setTime() {
    var ctr;
    $(".icon-play").each(function () {
      if ($(this).parent().hasClass('hide')) ctr = ($(this).attr('id')).split('_');
    });

    ++totalSeconds;
    $("#hour_" + ctr[1]).text(pad(Math.floor(totalSeconds / 3600)));
    $("#min_" + ctr[1]).text(pad(Math.floor((totalSeconds / 60) % 60)));
    $("#sec_" + ctr[1]).text(pad(parseInt(totalSeconds % 60)));
  }
}

pad() just adds leading zeros

I got this function that starts a timer on this format 00:00:00 whenever I click on a button. But I don't know how to do functions resume and pause. I've found some snippets that I thought could be helpful but I couldn't make those work. I'm new to using objects in js.

function clock() {
  var pauseObj = new Object();

  var totalSeconds = 0;
  var delay = setInterval(setTime, 1000);

  function setTime() {
    var ctr;
    $(".icon-play").each(function () {
      if ($(this).parent().hasClass('hide')) ctr = ($(this).attr('id')).split('_');
    });

    ++totalSeconds;
    $("#hour_" + ctr[1]).text(pad(Math.floor(totalSeconds / 3600)));
    $("#min_" + ctr[1]).text(pad(Math.floor((totalSeconds / 60) % 60)));
    $("#sec_" + ctr[1]).text(pad(parseInt(totalSeconds % 60)));
  }
}

pad() just adds leading zeros

• javascript
• jquery
• html
• setinterval
• pausing-execution

Share Improve this question Follow edited Sep 19, 2012 at 11:51 Danil Speransky 30.5k66 gold badges6969 silver badges7878 bronze badges asked Sep 19, 2012 at 1:24 esandrkwnesandrkwn 39911 gold badge66 silver badges1818 bronze badges

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4 Answers 4

Sorted by: Reset to default 20

I think it will be better if you will create clock object. See code (see Demo: http://jsfiddle.net/f9X6J/):

var Clock = {
  totalSeconds: 0,

  start: function () {
    var self = this;

    this.interval = setInterval(function () {
      self.totalSeconds += 1;

      $("#hour").text(Math.floor(self.totalSeconds / 3600));
      $("#min").text(Math.floor(self.totalSeconds / 60 % 60));
      $("#sec").text(parseInt(self.totalSeconds % 60));
    }, 1000);
  },

  pause: function () {
    clearInterval(this.interval);
    delete this.interval;
  },

  resume: function () {
    if (!this.interval) this.start();
  }
};

Clock.start();

$('#pauseButton').click(function () { Clock.pause(); });
$('#resumeButton').click(function () { Clock.resume(); });

Just clearing the interval wouldn't work, because totalSeconds would not get incremented. I would set up a flag that determines if the clock is paused or not.

This flag would be simply set upon calling pause() or unset upon resume(). I separated the totalSeconds increase to a 'tick' timeout that will always be running, even when paused (so that we can keep track of the time when we resume).

The tick function will therefore only update the time if the clock is not paused.

function clock()
{
    var pauseObj = new Object();

    var totalSeconds = 0;
    var isPaused = false;
    var delay = setInterval(tick, 1000);

    function pause()
    {
        isPaused = true;
    }

    function resume()
    {
        isPaused = false;
    }

    function setTime()
    {
        var ctr;
        $(".icon-play").each(function(){
            if( $(this).parent().hasClass('hide') )
                ctr = ($(this).attr('id')).split('_');
        });

        $("#hour_" + ctr[1]).text(pad(Math.floor(totalSeconds/3600)));
        $("#min_" + ctr[1]).text(pad( Math.floor((totalSeconds/60)%60)));
        $("#sec_" + ctr[1]).text(pad(parseInt(totalSeconds%60)));
    }

    function tick()
    {
        ++totalSeconds;

        if (!isPaused)
           setTime();
    }
}

Use window.clearInterval to cancel repeated action which was set up using setInterval().

clearInterval(delay);

    <html>
    <head><title>Timer</title>
    <script>

    //Evaluate the expression at the specified interval using setInterval()
    var a = setInterval(function(){disp()},1000);

    //Write the display() for timer
    function disp()
    {
         var x = new Date(); 

         //locale is used to return the Date object as string
         x= x.toLocaleTimeString();

        //Get the element by ID in disp()
        document.getElementById("x").innerHTML=x;
    }
    function stop()
    {
         //clearInterval() is used to pause the timer
        clearInterval(a);
    }
    function start()
    {    
        //setInterval() is used to resume the timer
        a=setInterval(function(){disp()},1000);
    }

    </script>
    </head>
    <body>
    <p id = "x"></p>
    <button onclick = "stop()"> Pause </button>
    <button onclick = "start()"> Resume </button>
    </body>
    </html>

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