checkbox based input item

Give the inputs for the number of sets a name also: name="sets[]".
Remove the onChange part that you already have.

Then, in the jQuery part that starts with $(document).ready .. insert this:

Code:

    $("input[name='sets[]']").change(function(){
        row = $(this).parents('tr');
        n = $(this).val();
        f = row.find("input[name='india[]']").val();
        total = n * f;
        alert(total);
    });

Now, if you change any of the inputs with the name "sets[]", it will trigger a calculation.

Not working
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echo '<td id="textone_'.$row['id'].'">'.$row['fee']. '</td>'; 
  echo '<td id="texttwo_'.$row['id'].'"> 
  <input type="number" min="0" max="999" name="india"  
   class="txtbox" disabled="disabled" ></td>';
   echo '<td> <input type="text" value="0"
   id="result_'.$row['id'].'" name="result"></td>';


<script src="//ajax.googleapis.com/ajax/libs/jquery/3.1.0/jquery.min.js"></script> 
 <script type="text/javascript">
$(document).ready(function(){
$("input[name='sets[]']").change(function(){
        row = $(this).parents('tr');
        n = $(this).val();
        f = row.find("input[name='india[]']").val();
        total = n * f;
        alert(total);
    });

</script>