Display Realtime Date and Time using JavaScript

setInterval() is a method that can be used to execute JavaScript script at specified intervals. We use it to display time from Date() class.

HTML

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

JavaScript

<script type="text/javascript">
  var time = document.getElementById("time");
  function showTime() {
    var date = new Date().toLocaleString("en-US", {timeZone: "Asia/Singapore"});    
    time.innerHTML = date;
  }
  setInterval(showTime, 1000);
</script>

With custom format

<script type="text/javascript">
	var time = document.getElementById("time");
	function showTime() {
	  var d = new Date();				  			 
	  time.innerHTML = d.getFullYear() + '-' + d.getMonth() + '-' + d.getDate() + ' ' + d.getHours() + ":" + d.getMinutes() + ":" + d.getSeconds();
	}
	setInterval(showTime, 1000);
</script>