<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>iframe creation/deletion test</title>
</head>
<body>
  <div id="yay"></div>
  <script type="text/javascript">
    "use strict";

    var yay = document.querySelector("#yay");
    yay.textContent = "nothing";

    // Create a promise that the test can wait for.
    let resolveReadyPromise;
    window.readyPromise = new Promise(r => (resolveReadyPromise = r));

    // Create/remove an iframe before load.
    var iframe = document.createElement("iframe");
    document.body.appendChild(iframe);
    iframe.remove();
    yay.textContent = "before events";

    // Create/remove an iframe on DOMContentLoaded.
    document.addEventListener("DOMContentLoaded", function() {
      const newIframe = document.createElement("iframe");
      document.body.appendChild(newIframe);
      newIframe.remove();
      yay.textContent = "DOMContentLoaded";
    });

    // Create/remove an iframe on window load.
    window.addEventListener("load", function() {
      const newIframe = document.createElement("iframe");
      document.body.appendChild(newIframe);
      newIframe.remove();
      yay.textContent = "load";

      resolveReadyPromise();
    });
  </script>
</body>
</html>
