Set Interval with pause and resume

index.html

<script>
function RecurringTimer(callback, delay) {
    var timerId, start, remaining = delay;

    this.pause = function() {
        window.clearTimeout(timerId);
        remaining -= new Date() - start;
    };

    var resume = function() {
        start = new Date();
        timerId = window.setTimeout(function() {
            remaining = delay;
            resume();
            callback();
        }, remaining);
    };
    
    this.resume = resume;

    this.resume();
}

var timer = new RecurringTimer(function() {
    document.getElementById("counter").innerHTML = ++count;
}, 1000);

var count = 0;
</script>

<input type="button" value="pause" onclick="timer.pause()">
<input type="button" value="resume" onclick="timer.resume()">
<div>Count: <b id="counter">0</b></div>