<html>
<head>
  <script type="text/javascript">
    function remove() {
      const frame = document.getElementById("sub-frame");
      const div = document.getElementById("delete");
      div.removeChild(frame);
    }
  </script>
</head>

<!-- unload handler prevents the page from being added to the bfcache on navigation -->
<body onunload="">
  <div id="delete">
    <iframe src="subframe.html" id="sub-frame"></iframe>
  </div>
</body>
</html>