JSFiddle - React, Tailwind, and code Playground

HTML

<td class="qty">
  <input type='text' name='qty' id='qty' value='1' />
</td>
<td class="unit-price hidden-xs">
  <span class="currency">
                      Rs
                    </span>
  <input type='text' name='price' id='price' value='100' />
</td>
<td class="total-price">
  <span class="currency">
                      Rs
                    </span>
  <input type='text' name='total' id='total' value='' />
</td>

JavaScript

$('#qty, #price').on('input', function() {
  var qty = parseInt($('#qty').val());
  var price = parseFloat($('#price').val());
  $('#total').val((qty * price ? qty * price : 0).toFixed(2));
});