In contrast to a countdown timer, here we will be looking at the opposite a timer ( counter ) that works like a stopwatch.
The code looks like this:
<p>Timer Demo</p>
<p id="demo"></p>
<script>
var start = Date.now();
setInterval(function() {
// milliseconds elapsed since start
var delta = Date.now() - start;
// convert milliseconds to seconds
given_seconds = (Math.floor(delta / 1000));
// calculate hour/mins/sec's based on given seconds
hours = Math.floor(given_seconds / 3600);
minutes = Math.floor((given_seconds - (hours * 3600)) / 60);
seconds = given_seconds - (hours * 3600) - (minutes * 60);
//Format the time with two digits per hour/mins/sec's
timeString = hours.toString().padStart(2, '0') + ':' +
minutes.toString().padStart(2, '0') + ':' +
seconds.toString().padStart(2, '0');
//Print the current time so far
document.getElementById("demo").innerHTML = timeString;
}, 1000); // update about every second
</script>
Simply copy paste the code to the HTML section in your appearance settings.

You can see a working demo of this here:
https://test2.leadshook.io/survey/ex8YutWr2DAW05wd5vmB18OMAeyreLfUPiedaKWh