Demo
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<html>
<body onload="startTime()">
<h2>Time is:</h2>
<div id="txt"></div>
<script>
function startTime() {
const now= new Date();
let h = now.getHours();
let m = now.getMinutes();
let s = now.getSeconds();
m = checkTime(m);
s = checkTime(s);
document.getElementById('txt').innerHTML = h + ":" + m + ":" + s;
setTimeout(startTime, 1000);
}
function checkTime(i) {
if (i < 10) {i = "0" + i}; // add zero in front of numbers < 10
return i;
}
</script>
</body>
</html>
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