Clock in JavaScript displaying current date and time with refresh rate of 1 sec

Real time changing Clock showing date and time

We can display a clock which will be showing the local time of the client computer by using JavaScript. Note that this time displayed is taken from user computer and not from the server.

JavaScript real time clock showing change in date and time in different formats

We have seen in our date object example how to display current date and time where the current date and time is displayed once. Here we will try to display changing clock or real time change in date and time by using setTimeout function. This setTimeout function we have used to trigger the time display function in a refresh rate of 1000 mill seconds ( 1 Sec ). This refresh rate can be changed to any other value. By changing the value to 5000 the clock will refresh and show the exact time once in every 5 seconds.

Here is the demo of this script and code is given below that.

Here is the code


<html>
<head>
<title>(Type a title for your page here)</title>
<script type="text/javascript"> 
function display_c(){
var refresh=1000; // Refresh rate in milli seconds
mytime=setTimeout('display_ct()',refresh)
}

function display_ct() {
var x = new Date()
document.getElementById('ct').innerHTML = x;
display_c();
 }
</script>
</head>

<body onload=display_ct();>
<span id='ct' ></span>

</body>
</html>

Changing the display format

To change the display format we need to change the function part only where we can change the display part.
Let us start with using UTC string

function display_ct() {
var x = new Date()
var x1=x.toUTCString();// changing the display to UTC string
document.getElementById('ct').innerHTML = x1;
tt=display_c();
 }

The output is here

Displaying in mm/dd/yy H:m:s format

Here is the code

function display_ct() {
var x = new Date()
var x1=x.getMonth() + 1+ "/" + x.getDate() + "/" + x.getFullYear(); 
x1 = x1 + " - " +  x.getHours( )+ ":" +  x.getMinutes() + ":" +  x.getSeconds();
document.getElementById('ct').innerHTML = x1;
display_c();
 }

Note that we have only changed the display_ct() function part , other code remains same. Here is the output

Displaying AM or PM with clock

<script>

function display_ct5() {
var x = new Date()
var ampm = x.getHours( ) >= 12 ? ' PM' : ' AM';

var x1=x.getMonth() + 1+ "/" + x.getDate() + "/" + x.getFullYear(); 
x1 = x1 + " - " +  x.getHours( )+ ":" +  x.getMinutes() + ":" +  x.getSeconds() + ":" + ampm;
document.getElementById('ct5').innerHTML = x1;
display_c5();
 }
 function display_c5(){
var refresh=1000; // Refresh rate in milli seconds
mytime=setTimeout('display_ct5()',refresh)
}
display_c5()
</script>
<span id='ct5' style="background-color: #FFFF00"></span>

Displaying 12 hours format

<script>function display_ct6() {
var x = new Date()
var ampm = x.getHours( ) >= 12 ? ' PM' : ' AM';
hours = x.getHours( ) % 12;
hours = hours ? hours : 12;
var x1=x.getMonth() + 1+ "/" + x.getDate() + "/" + x.getFullYear(); 
x1 = x1 + " - " +  hours + ":" +  x.getMinutes() + ":" +  x.getSeconds() + ":" + ampm;
document.getElementById('ct6').innerHTML = x1;
display_c6();
 }
 function display_c6(){
var refresh=1000; // Refresh rate in milli seconds
mytime=setTimeout('display_ct6()',refresh)
}
display_c6()
</script>
<span id='ct6' style="background-color: #FFFF00"></span>

Add one leading zero to all single digit in month , date, hour , minute and seconds.

<script>function display_ct7() {
var x = new Date()
var ampm = x.getHours( ) >= 12 ? ' PM' : ' AM';
hours = x.getHours( ) % 12;
hours = hours ? hours : 12;
hours=hours.toString().length==1? 0+hours.toString() : hours;

var minutes=x.getMinutes().toString()
minutes=minutes.length==1 ? 0+minutes : minutes;

var seconds=x.getSeconds().toString()
seconds=seconds.length==1 ? 0+seconds : seconds;

var month=(x.getMonth() +1).toString();
month=month.length==1 ? 0+month : month;

var dt=x.getDate().toString();
dt=dt.length==1 ? 0+dt : dt;

var x1=month + "/" + dt + "/" + x.getFullYear(); 
x1 = x1 + " - " +  hours + ":" +  minutes + ":" +  seconds + " " + ampm;
document.getElementById('ct7').innerHTML = x1;
display_c7();
 }
 function display_c7(){
var refresh=1000; // Refresh rate in milli seconds
mytime=setTimeout('display_ct7()',refresh)
}
display_c7()
</script>
<span id='ct7' style="background-color: #FFFF00"></span>

To display clock inside a textbox

Create a textbox and give id to it

<input type=text id='t1' size='70'>

For displaying add this line inside the function display_ct()

document.getElementById('t1').value = x;

Changing font size and font color of display

document.getElementById('ct3').style.fontSize='30px';
document.getElementById('ct3').style.color='#0030c0';
document.getElementById('ct3').innerHTML = x2;

Adding 0 to single digit numbers

We can display 5 hours as 05 hours or 2 minutes as 02 minutes.

// date part ///
var month=x.getMonth()+1;
var day=x.getDate();
var year=x.getFullYear();
if (month <10 ){month='0' + month;}
if (day <10 ){day='0' + day;}
var x3= month+'-'+day+'-'+year;

// time part //
var hour=x.getHours();
var minute=x.getMinutes();
var second=x.getSeconds();
if(hour <10 ){hour='0'+hour;}
if(minute <10 ) {minute='0' + minute; }
if(second<10){second='0' + second;}
var x3 = x3 + ' ' +  hour+':'+minute+':'+second

<span id='ct4' style="background-color:#FFFF00"></span>

Displaying Server time using Ajax

This script uses JavaScript to read client computer time and display the same. By using PHP or any other server side script we can display server time. But here we can get once the time that is the time of the page rendered from server. To display updated or real time clock showing server time we have to send request to server periodically. To do this we can use Ajax to get current date and time from server and display in one second interval.

Toggling the display of clock by a button ( using Jquery)

Read how we can toggle the display of the clock by controlling from a button.

Draw Analog Clock on Canvas using Jquery or JavaScript.

This article is written by plus2net.com team.

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