JSFiddle - React, Tailwind, and code Playground

HTML

<script src="//code.jquery.com/jquery-1.11.0.min.js"></script>
<form onsubmit="return false">
  <legend>Test Environment.... Tax Deduction</legend>

  <p><label for="earnamount">&nbsp;&nbsp;Earn Amount</label>
  <input type="number" id="earnamount" name="earnamount"></p>

  <p><label for="taxdeduction">&nbsp;Tax Deduction</label>
  <input type="number" id="taxdeduction" value="0.02" name="taxdeduction"></p>

  <p><label for="amountpayable">Amount Payable</label>
  <input type="number" id="amountpayable" name="amountpayable"></p>

  <p>Total Tax In: <strong>USD: <output name="amount" for="earnamount taxdeduction">0</output></strong></p>
</form>

JavaScript

$(function() {
  return $('#earnamount, #taxdeduction').change(function() {
    var earn_amount, tax_rate, tax_total, total;
    earn_amount = parseFloat($('#earnamount').val());
    tax_rate = parseFloat($('#taxdeduction').val());
    tax_total = earn_amount * tax_rate;
    total = earn_amount - tax_total;
    $('#amountpayable').val(total);
    return $('output[name="amount"]').text(tax_total);
  });
});