While @Jonas Giuro is right when saying that:
You cannot PAUSE the setInterval function, you can either STOP it (clearInterval), or let it run
On the other hand this behavior can be simulated with approach @VitaliyG suggested:
You shouldn't measure time in interval function. Instead just save time when timer was started and measure difference when timer was stopped/paused. Use setInterval only to update displayed value.
var output = $('h1');_x000D_
var isPaused = false;_x000D_
var time = new Date();_x000D_
var offset = 0;_x000D_
var t = window.setInterval(function() {_x000D_
if(!isPaused) {_x000D_
var milisec = offset + (new Date()).getTime() - time.getTime();_x000D_
output.text(parseInt(milisec / 1000) + "s " + (milisec % 1000));_x000D_
}_x000D_
}, 10);_x000D_
_x000D_
//with jquery_x000D_
$('.toggle').on('click', function(e) {_x000D_
e.preventDefault();_x000D_
isPaused = !isPaused;_x000D_
if (isPaused) {_x000D_
offset += (new Date()).getTime() - time.getTime();_x000D_
} else {_x000D_
time = new Date();_x000D_
}_x000D_
_x000D_
});
_x000D_
h1 {_x000D_
font-family: Helvetica, Verdana, sans-serif;_x000D_
font-size: 12px;_x000D_
}
_x000D_
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>_x000D_
<h1>Seconds: 0</h1>_x000D_
<button class="toggle">Toggle</button>
_x000D_