Tryit Editor v2.9

Edit This Code:
<!DOCTYPE html>
<html>
<body>

<p id="demo">Clock</p>

<button onclick="clearInterval(myTimer)">Stop</button>

<script>
var myTimer = setInterval(myClock, 1000);
function myClock() {
    document.getElementById("demo").innerHTML =
    new Date().toLocaleTimeString();
}
</script>

</body>
</html>