image-loading-lazy-to-eager.html

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This WPT test may be referenced by the following Test IDs:
- /html/semantics/embedded-content/the-img-element/image-loading-lazy-to-eager.html - WPT Dashboard Interop Dashboard

<!DOCTYPE html>

<head>

  <title>Below-viewport images with loading='lazy' load when set to

         loading='eager' or the `loading` attribute is removed</title>

  <link rel="author" title="Dom Farolino" href="mailto:domfarolino@gmail.com">

  <link rel="help" href="https://html.spec.whatwg.org/multipage/embedded-content.html#attr-img-loading">

  <script src="/resources/testharness.js"></script>

  <script src="/resources/testharnessreport.js"></script>

</head>

<script>

  const t = async_test("Below-viewport images with loading='lazy' load when " +

                       "set to loading='eager' or the `loading` attribute is " +

                       "removed");

  const img_1_onload = t.unreached_func("#img_1 should not load before the " +

                                        "window load event");

  const img_2_onload = t.unreached_func("#img_2 should not load before the " +

                                        "window load event");

  window.addEventListener("load", t.step_func(() => {

    const img_1 = document.querySelector('#img_1');

    const img_2 = document.querySelector('#img_2');

    const img_1_promise = new Promise((resolve, reject) => {

      img_1.onerror = reject;

      img_1.onload = resolve;

});

    const img_2_promise = new Promise((resolve, reject) => {

      img_2.onerror = reject;

      img_2.onload = resolve;

});

    Promise.all([img_1_promise, img_2_promise])

      .then(t.step_func_done())

      .catch(t.unreached_func("The images should load successfully"));

    // Kick off the requests.

    img_1.loading = 'eager';

    img_2.removeAttribute('loading'); // unset the attribute, putting it in

                                      // the default (eager) state.

  }));

</script>

<body>

  <div style="height:1000vh;"></div>

  <img id="img_1"

       src="resources/image.png?lazy-to-eager-1"

       loading="lazy" onload="img_1_onload();">

  <img id="img_2"

       src="resources/image.png?lazy-to-eager-2"

       loading="lazy" onload="img_2_onload();">

</body>