<!DOCTYPE html>
<html>

  <head>
    <link rel="stylesheet" href="style.css">
    <script src="script.js"></script>
  </head>

  <body>
    <iframe src="something.html"></iframe>
  <div id="log"></div>
  </body>
</html>
document.addEventListener('DOMContentLoaded', function() {
  if (window.location.search) {
    var log = '<h4>Form values submitted:</h4>';
    var search = window.location.search.substr(1);
    search.split('&').forEach(function(value) {
      var parts = value.split('=');
      log += parts[0]+' : '+parts[1]+'<br/>';
    })
    document.getElementById('log').innerHTML = log;
  }
  /*
  if (document.forms.length) {
    console.log('forms have length');
    document.forms[0].addEventListener('submit', function() {
      console.log('form submitted');
    })
  }*/
});
/* Styles go here */

<!DOCTYPE html>
<html>

<head>
  <link rel="stylesheet" href="style.css">
  <!--<script src="script.js"></script>-->
</head>

<body>
  <form action="index.html" target="_parent">
    <input type="text" value="3" name="qty" />
    <input type="submit" name="submit" value="submit">
  </form>
</body>

</html>