checkbox based input item

To toggle the disabled property of the text inputs, first give all text and number inputs a class name and the disabled property: class="txtbox" disabled="disabled".
Then give the checkboxes the class name "cbx".

Load jQuery. Insert the following script:

Code:

<script>

$(document).ready(function(){
    $('.cbx').click(function(){
        v = $(this).is(':checked');
        row = $(this).parents('tr');
        if (v==true) {
            row.find('.txtbox').removeAttr('disabled');    
        }
        else {
            row.find('.txtbox').attr('disabled','disabled');
        }
        
    });

});

</script>

Now, if you click on one of the checkboxes, the text and number inputs on the same row are enabled or disabled.


Important:

Code:

$('.cbx')

is jQuery code for document.getElementsByClassName('cbx')
As you can see, jQuery makes your code far more simple!

Working perfectly.
Thanks a lot. You are the real programmer.
one more queries.
I want to multiply first and second field result should be in third field. It has 7 rows.

echo '<td id="textone_'.$row['id'].'">'.$row['fee']. '</td>'; 
  echo '<td  id="texttwo_'.$row['id'].'"> <input type="number" min="0" max="999" 
  name="india"  
  onChange="sum('.$row['id'].'); " class="txtbox" disabled="disabled" ></td>';
echo '<td> <input type="text" value="0"

   id="result_'.$row['id'].'" name="result"></td>';
Ajax 
****

<script src="//ajax.googleapis.com/ajax/libs/jquery/3.1.0/jquery.min.js"></script> 

<!--<script src="<?php echo base_url(); ?>assets/jQuery-2.1.4.min.js"></script> -->

<script type="text/javascript">
 function sum(rowid) {
       var txtFirstNumberValue =  document.getElementById('textone_'+rowid).innerHTML;
       alert(txtFirstNumberValue );
       var txtSecondNumberValue = document.getElementById('texttwo_'+rowid).value;
       alert(txtSecondNumberValue ); 
       
       var result = parseInt(txtFirstNumberValue) * parseInt(txtSecondNumberValue);
       alert(result);
       if (!isNaN(result)) {
           document.getElementById('result_'+rowid).value = result;
       }
   }
  </script>

alert(txtSecondNumberValue ) shows undefined error.
how to solve this?