<!DOCTYPE html>
<head>
  <title>Deferred iframes with loading='lazy' use the original
         base URL specified at parse-time</title>
  <link rel="author" title="Rob Buis" href="mailto:rbuis@igalia.com">
  <script src="/resources/testharness.js"></script>
  <script src="/resources/testharnessreport.js"></script>
  <script src="../resources/common.js"></script>
  <base href='/html/semantics/embedded-content/the-iframe-element/resources/'>
</head>

<script>
  const below_viewport_iframe = new ElementLoadPromise("below-viewport");

  let has_window_loaded = false;

  async_test(t => {
    // Change the base URL and scroll down to load the deferred iframe.
    window.addEventListener("load", t.step_func(() => {
      const base = document.querySelector('base');
      base.href = '/invalid-url-where-no-subresources-exist/';
      has_window_loaded = true;
      below_viewport_iframe.element().scrollIntoView();
    }));

    below_viewport_iframe.promise.then(
      t.step_func_done(() => {
        assert_true(has_window_loaded,
                    "Below-viewport loading=lazy iframes do not block the " +
                    "window load event");
        assert_true(below_viewport_iframe.element().contentDocument.body.
                    innerHTML.includes("<p>Subframe</p>"),
                    "The loading=lazy iframe's content is accessible upon loading");
    }));

  }, "When a loading=lazy iframe is loaded, it loads relative to the " +
     "document's base URL computed at parse-time.");
</script>

<body>
  <div style="height:1000vh"></div>
  <iframe id="below-viewport" src="subframe.html" loading="lazy"
          width="200px" height="100px" onload="below_viewport_iframe.resolve()">
  </iframe>
</body>
