Stopwatch.js Demo

<label class="time"></label>
<button class="start">Start</button>
<button class="pause">Pause</button>
<button class="stop">Stop</button>

<script>
var stopwatch = new Stopwatch();

var start = document.querySelector('.start');
start.addEventListener('click', function() {
  stopwatch.start();
});

var pause = document.querySelector('.pause');
pause.addEventListener('click', function() {
  stopwatch.pause();
});

var stop = document.querySelector('.stop');
stop.addEventListener('click', function() {
  stopwatch.stop();
});

var time = document.querySelector('.time');
setInterval(function() {
  time.innerHTML = stopwatch;
}, 5);
</script>