How to show current time in JavaScript in the format HH:MM:SS?

How do I show the current time in the format HH:MM:SS?

You can use native function Date.toLocaleTimeString():

var d = new Date();
var n = d.toLocaleTimeString();

This will display e.g.:

"11:33:01"

MDN: Date toLocaleTimeString

var d = new Date();
var n = d.toLocaleTimeString();
alert("The time is: n"+n);

function checkTime(i) {
  if (i < 10) {
    i = "0" + i;
  }
  return i;
}

function startTime() {
  var today = new Date();
  var h = today.getHours();
  var m = today.getMinutes();
  var s = today.getSeconds();
  // add a zero in front of numbers<10
  m = checkTime(m);
  s = checkTime(s);
  document.getElementById('time').innerHTML = h + ":" + m + ":" + s;
  t = setTimeout(function() {
    startTime()
  }, 500);
}
startTime();

<div id="time"></div>

DEMO using javaScript only

Update

Updated Demo

(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();
})();

You can do this in Javascript.

var time = new Date();
console.log(time.getHours() + ":" + time.getMinutes() + ":" + time.getSeconds());

At present it returns 15:5:18. Note that if any of the values are less than 10, they will display using only one digit, not two.

Check this in JSFiddle

Updates:
For prefixed 0’s try

var time = new Date();
console.log(
    ("0" + time.getHours()).slice(-2)   + ":" + 
    ("0" + time.getMinutes()).slice(-2) + ":" + 
    ("0" + time.getSeconds()).slice(-2));

You can use moment.js to do this.

var now = new moment();
console.log(now.format("HH:mm:ss"));

Outputs:

16:30:03

new Date().toTimeString().slice(0,8)

Note that toLocaleTimeString() might return something like 9:00:00 AM.

Use this way:

var d = new Date();
localtime = d.toLocaleTimeString('en-US', { hour12: false });

Result: 18:56:31

function realtime() {
  
  let time = moment().format('h:mm:ss a');
  document.getElementById('time').innerHTML = time;
  
  setInterval(() => {
    time = moment().format('h:mm:ss a');
    document.getElementById('time').innerHTML = time;
  }, 1000)
}

realtime();

<script src="https://cdnjs.cloudflare.com/ajax/libs/moment.js/2.22.1/moment.min.js"></script>

<div id="time"></div>

A very simple way using moment.js and setInterval.

setInterval(() => {
  moment().format('h:mm:ss a');
}, 1000)

Sample output

Using setInterval() set to 1000ms or 1 second, the output will refresh every 1 second.

3:25:50 pm

This is how I use this method on one of my side projects.

setInterval(() => {
  this.time = this.shared.time;
}, 1000)

Maybe you’re wondering if using setInterval() would cause some performance issues.

Is setInterval CPU intensive?

I don’t think setInterval is inherently going to cause you significant performance problems. I suspect the reputation may come from an earlier era, when CPUs were less powerful. … – lonesomeday

No, setInterval is not CPU intensive in and of itself. If you have a lot of intervals running on very short cycles (or a very complex operation running on a moderately long interval), then that can easily become CPU intensive, depending upon exactly what your intervals are doing and how frequently they are doing it. … – aroth

But in general, using setInterval really like a lot on your site may slow down things. 20 simultaneously running intervals with more or less heavy work will affect the show. And then again.. you really can mess up any part I guess that is not a problem of setInterval. … – jAndy

new Date().toLocaleTimeString('it-IT')

The it-IT locale happens to pad the hour if needed and omits PM or AM 01:33:01

This code will output current time in HH:MM:SS format in console, it takes into account GMT timezones.

var currentTime = Date.now()
var GMT = -(new Date()).getTimezoneOffset()/60;
var totalSeconds = Math.floor(currentTime/1000);
seconds = ('0' + totalSeconds % 60).slice(-2);
var totalMinutes = Math.floor(totalSeconds/60);
minutes = ('0' + totalMinutes % 60).slice(-2);
var totalHours = Math.floor(totalMinutes/60);
hours = ('0' + (totalHours+GMT) % 24).slice(-2);
var timeDisplay = hours + ":" + minutes + ":" + seconds;
console.log(timeDisplay);
//Output is: 11:16:55

Compact clock function:

setInterval(function() {
    let d = new Date()
    console.log(`${d.getHours()}:${d.getMinutes()}:${d.getSeconds()}`)
}, 1000);

new Date().toLocaleTimeString()

Use

Date.toLocaleTimeString()

// Depending on timezone, your results will vary
const event = new Date('August 19, 1975 23:15:30 GMT+00:00');

console.log(event.toLocaleTimeString('en-US'));
// expected output: 1:15:30 AM

console.log(event.toLocaleTimeString('it-IT'));
// expected output: 01:15:30

console.log(event.toLocaleTimeString('ar-EG'));
// expected output: ١٢:١٥:٣٠

Source