docwrite_creates_subframe.html | Explore in Territory

<html>
<body>
<iframe src="/slow?100" id="iframe"></iframe>
<script>
  // slow takes 100 seconds to load, plenty of time to overwrite the
  // provisional load.
  iframe = document.getElementById("iframe");
  let doc = iframe.contentDocument;

  doc.open();
  doc.write("<html><body>Rewritten. <iframe name='grandchild'></iframe></body></html>");
  doc.close();
</script>
</body>
</html>

chromium/components/test/data/subresource_filter/docwrite_creates_subframe.html