<!DOCTYPE html>
<html>
<head>
<title>Writing out a document with form controls with values</title>
<link rel="author" href="mailto:bzbarsky@mit.edu"/>
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
</head>
<body>
<div id="log"></div>
<script>
function asyncHop(t, arg) {
  return new Promise(res => t.step_timeout(res.bind(null, arg), 0));
}

function loadPromise(t, iframe) {
  var p = new Promise(res =>
    iframe.addEventListener("load", res.bind(null, iframe), { once: true }));
  // We need to do one trip through the event loop to make sure we're
  // not still under the load event firing when we start doing our
  // document.open bits.
  return p.then(asyncHop.bind(null, t));
}

async function createIframe(t) {
  var i = document.createElement("iframe");
  t.add_cleanup(() => i.remove());
  var p = loadPromise(t, i);
  document.body.appendChild(i);
  return p;
}

async function replaceIframe(t, i, text) {
  var p = loadPromise(t, i);
  var doc = i.contentDocument;
  doc.open();
  doc.write(text);
  doc.close();
  return p;
}

promise_test(async function(t) {
  var i = await createIframe(t);
  var str = "<textarea>123</textarea>";
  await replaceIframe(t, i, str);
  i.contentDocument.querySelector("textarea").value = "abc";
  await replaceIframe(t, i, str);
  assert_equals(i.contentDocument.querySelector("textarea").value, "123");
}, "textarea state");

promise_test(async function(t) {
  var i = await createIframe(t);
  var str = "<input value='123'>";
  await replaceIframe(t, i, str);
  i.contentDocument.querySelector("input").value = "abc";
  await replaceIframe(t, i, str);
  assert_equals(i.contentDocument.querySelector("input").value, "123");
}, "input state");
</script>
</body>
</html>