Timer
by Lestrae
HTML
<div>
<span id='minutes'></span>:<span id='seconds'></span>
</div>
JavaScript
let minutes = 0;
let seconds = 0;
setInterval(function timer() {
seconds = ++seconds;
if (seconds == 60) minutes++;
document.getElementById('minutes').innerHTML = minutes;
document.getElementById('seconds').innerHTML = seconds;
}, 1000);