JAVASCRIPT

check change event in jquery

<div class="form-group">
    <label class="w-20" id="loan_no_label"><?= "<font class='red'> * </font>" . __('loan-number') ?></label>
	<input class="w-65 form-control" id="loan_no" required type="text" name="loan_no" />
</div>

$('#is_all_loan').on('click', function() {

   var checked = $(this);
   if (checked.is(':checked')) {
     $('#loan_no_label').html('<?= __('loan-number'); ?>');
     $('#loan_no').attr('required', false); 

   } else {
     $('#loan_no_label').html("<font class='red'> * </font>貸款編號");
     $('#loan_no').attr('required', true); 
   }
 });

jquery on change

// modify #inputId selector as per your code
$( "#inputId" ).change(function() {
  alert( "Handler for .change() called." );
});

//OR
$("#InputId").on('change', function(){
    alert( 'Handler for "change" called.' );
});

// OR
$("body").on('change', '#InputId', function(){
    alert( 'Handler for "change" called.' );
});

jquery on change

$(document).on('change', 'input', function() {
  // Does some stuff and logs the event to the console
});

value change event jquery

$("#input").change(function(){
  alert("The text has been changed.");
});

jquery on element change

// On element change.
$('mydiv').bind('DOMSubtreeModified', function () {
  console.log('changed');
});