title: Why does IE give this error: Object doesn't support property or method isNaN
body: <p>I get this error in IE 11:</p>
  
  <blockquote>
    <p><code>Object doesn't support property or method isNaN</code></p>
  </blockquote>
  
  <p>JavaScript</p>
  
  <pre><code>jQuery(document).ready(function($) {
      var $total = $('#total'),
      $value = $('.value');
      $firstName = $('#firstname');
      $lastName = $('#lastname');
      $tour = $('#tour');
      $pledge = $('#pledge');
      $currency = $('#currency');
      $distance = $('#distance');
      $riders = $('#riders');
  
      $(':input').on('input change', function(e) {
          var total = 1;
          $value.each(function(index, elem) {
              if(!Number.isNaN(parseFloat(this.value)))
                  total = total * parseFloat(this.value);
          });
          $total.val(total/10);
  
          $('#pledgefirstname').text($firstName.val());
          $('#pledgelastname').text($lastName.val());
          $('#pledgetour').text($tour.val());
          $('#pledgepledge').text($pledge.val());
          $('#pledgecurrency').text($currency.val());
          $('#pledgecurrency2').text($currency.val());
          $('#pledgecurrency3').text($currency.val());
          $('#pledgecurrency4').text($currency.val());
          $('#pledgetotal').text($total.val());
          $('#pledgetotal2').text($total.val());
          $('#pledgedistance').text($distance.val());
          $('#pledgeriders').text($riders.val());
      });
  });
  </code></pre>