How can I calculate duration in seconds for more rows from two times?

How can I calculate duration in seconds for more rows from two times?

<!--Time calculation-->

<script src=""></script>
$(document).ready(function() {
 //this calculates values automatically
 $("#start_time, #end_time").on("keydown keyup", function() {
function sum() {
 var start_time = document.getElementById('start_time').value;
 var end_time = document.getElementById('end_time').value;
 var result = parseInt(end_time) - parseInt(start_time);

 if (!isNaN(result)) {
 document.getElementById('sum').value = result;


<!--add row-->

function addRow(tableID) {
    var table = document.getElementById(tableID);
    var rowCount = table.rows.length;
        var row = table.insertRow(rowCount);
        var colCount = table.rows[0].cells.length; = 'row_'+rowCount;
        for (var i = 0; i < colCount; i++) {
            var newcell = row.insertCell(i);
            newcell.outerHTML = table.rows[0].cells[i].outerHTML;            
function deleteRow(tableID) {
    var table = document.getElementById(tableID);
    var rowCount = table.rows.length;
    for (var i = 0; i < rowCount; i++) {
        var row = table.rows[i];
        var chkbox = row.cells[0].childNodes[0];
        if (null !== chkbox && true === chkbox.checked) {
            if (rowCount <= 1) { // limit the user from removing all the fields
                alert("Cannot Remove all the Passenger.");


<form method="post" action="action_entry_history.php" name="form">

    <TABLE id="dataTable" width="100%" border="1" align="center">
<tr id='row_0'>
<td><INPUT type="checkbox" size="5" name="chk"/></td>

<td><input type="time" name="start_time[]" size="5"  id="start_time"  step="1" placeholder="HH:MM:SS"/></td>
<td><input type="time" name="end_time[]" size="5"  id="end_time" step="1" placeholder="HH:MM:SS"/></td>
<td><input type="text" id="sum"  size="5" name="duration[]" placeholder="Duration" readonly></td>

        <INPUT type="button" value="Add Row" onClick="addRow('dataTable')" />
        <INPUT type="button" value="Delete Row" onClick="deleteRow('dataTable')" />
        <input type="submit" value="Submit" name="submit">

Honestly, I haven’t understood anything from your question. Could you please describe it more detail?

I have two fields
1)Start_time and
I want to calculate duration from these.

As long as Start_time and end_time are in a “code friendly” format it will be as simple as subtracting Start_time from end_time.

Are they always guaranteed to be “HH:MM:SS” and never anything else?

I need duration in seconds.

I made an example that you can use:

Take a note that it works only with “HH:MM:SS (AM|PM)” strings


How can i use it …onchange function()…?

document.getElementById('calcBtn').onclick = function(){
	var startTime = document.getElementById('startTimeInput').value;
	var endTime = document.getElementById('endTimeInput').value;
  var result = getDeltaSeconds(startTime, endTime);
  document.getElementById('result').innerHTML = result + ' sec';

function getDeltaSeconds(startTime, endTime){
	var startTimeSeconds = getSeconds(startTime);
  var endTimeSeconds = getSeconds(endTime);
  return endTimeSeconds - startTimeSeconds;	

function getSeconds(timeString){
	var parts = timeString.split(' ');
  var time = parts[0];
  var ampm = parts[1];
  var timeParts = time.split(':');
  var seconds = Number(timeParts[2]) + Number(timeParts[1]*60) + Number(timeParts[0]*60*60);
  return ampm == 'AM' ? seconds : seconds + 12*60*60;

This topic was automatically closed 91 days after the last reply. New replies are no longer allowed.