Tryit Editor v2.9

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

Time: <input type="time" id="myTime" value="16:32:55">

<p>Click the button to decrement the value of the time field by 10 minutes (each time you click).</p>

<button onclick="myFunction()">Try it</button>

<script>
function myFunction() {
    document.getElementById("myTime").stepDown(10);
}
</script>

</body>
</html>