function checkTime(i) {_x000D_
if (i < 10) {_x000D_
i = "0" + i;_x000D_
}_x000D_
return i;_x000D_
}_x000D_
_x000D_
function startTime() {_x000D_
var today = new Date();_x000D_
var h = today.getHours();_x000D_
var m = today.getMinutes();_x000D_
var s = today.getSeconds();_x000D_
// add a zero in front of numbers<10_x000D_
m = checkTime(m);_x000D_
s = checkTime(s);_x000D_
document.getElementById('time').innerHTML = h + ":" + m + ":" + s;_x000D_
t = setTimeout(function() {_x000D_
startTime()_x000D_
}, 500);_x000D_
}_x000D_
startTime();
_x000D_
<div id="time"></div>
_x000D_
DEMO using javaScript only
Update
(function () {
function checkTime(i) {
return (i < 10) ? "0" + i : i;
}
function startTime() {
var today = new Date(),
h = checkTime(today.getHours()),
m = checkTime(today.getMinutes()),
s = checkTime(today.getSeconds());
document.getElementById('time').innerHTML = h + ":" + m + ":" + s;
t = setTimeout(function () {
startTime()
}, 500);
}
startTime();
})();