<!DOCTYPE html>
<head>
  <title>In viewport images with loading='lazy' and changed to loading='eager'
         do not block the window load event</title>
  <link rel="author" title="Rob Buis" href="mailto:rbuis@igalia.com">
  <link rel="help" href="https://github.com/scott-little/lazyload">
  <script src="/resources/testharness.js"></script>
  <script src="/resources/testharnessreport.js"></script>
</head>

<script>
  const t = async_test("Test that in viewport images with loading='lazy' and " +
                       "changed to loading='eager' do not block the window " +
                       "load event.");

  let has_in_viewport_loaded = false;
  let has_window_loaded = false;

  const in_viewport_img_onload = t.step_func_done(function() {
    assert_false(has_in_viewport_loaded,
               "The in_viewport element should load only once.");
    assert_true(has_window_loaded,
               "The window load event should fire before in_viewport image loads.");
    has_in_viewport_loaded = true;
  });

  window.addEventListener("load", t.step_func(function() {
    assert_false(has_window_loaded,
                 "The window load event should only fire once.");
    has_window_loaded = true;
  }));
</script>

<body>
  <img id="in_viewport" src="resources/image.png?in-viewport-dynamic&pipe=trickle(d2)"
       loading="lazy" onload="in_viewport_img_onload();">
  <script>
    document.getElementById("in_viewport").loading = 'eager';
  </script>
</body>
