Display Leading Zeros On Input Number Fields

You can add an onchange attribute to your input tag, which calls a javascript function.

    <script>
       function MyFunction() {
           var minuteValue = document.getElementById("minutes").value;
           if (minuteValue.length < 2) {
               minuteValue = "0" + minuteValue;
           }
           alert(minuteValue);
       }
    </script>

    <input id="minutes" onchange="MyFunction()"/>