ถาม javascript เรื่องการผูก event กับ dynamic form input

$(document).ready(function() {

    $("input[type='number']").inputNumericTextBox();
   
   $('.percentage').on('change', function() {
       // do something ...............
   });


   $("#btn-add").click(function() {
        $('tr:last').clone().insertAfter($(this).parents('table').find('tbody tr:last'))
   });

});

<table>
<tr data-id="1" class="tr_input"><td>....</td><td>....</td></tr>
<tr data-id="2" class="tr_input"><td>....</td><td>....</td></tr>
<tr data-id="3" class="tr_input"><td>....</td><td>....</td></tr>
</table>

<script>
$(document).delegate('.tr_input td','click', function(){ 
   var tr = $(this).parent();
   alert( $(tr).data('id');
});