HTMLLinkElement-load-event-002.html

<!doctype html>
<meta charset="utf-8">
<title>Link element load event doesn't block the parser.</title>
<link rel="author" title="Emilio Cobos Álvarez" href="mailto:[email protected]">
<link rel="author" title="Mozilla" href="https://mozilla.org">
<link rel="help" href="https://html.spec.whatwg.org/#link-type-stylesheet">
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script>
  let NUM_LOADS = 0;

  function sheetUrl(token) {
    return "stylesheet-same-origin.css?" + token;
  }

  function createLink(token) {
    let link = document.createElement("link");
    link.rel = "stylesheet";
    link.href = sheetUrl(token);
    return link;
  }

  function waitForEnoughTimeToLoadSheet(token) {
    return new Promise(resolve => {
      let link = createLink(token);
      link.onload = resolve;
      document.head.appendChild(link);
    });
  }

  promise_test(async function (t) {
    let link = createLink("removed");
    link.addEventListener("load", t.unreached_func("got unexpected load event"));
    link.addEventListener("error", t.unreached_func("got unexpected error event"));
    document.head.appendChild(link);
    link.remove();

    await waitForEnoughTimeToLoadSheet("removed-wait");
  }, "Load event doesn't fire on removed link");

  promise_test(async function (t) {
    let link = createLink("changed-initial");
    let sawLoad = false;
    let load = new Promise(resolve => {
      link.addEventListener("load", function(e) {
        assert_false(sawLoad, "Should only see load event once");
        sawLoad = true;
        resolve();
      });
    });
    link.addEventListener("error", t.unreached_func("got unexpected error event"));
    document.head.appendChild(link);
    link.href = sheetUrl("changed-change");

    await waitForEnoughTimeToLoadSheet("changed-wait");
    await load;

    assert_true(sawLoad, "Should've seen the load event only once");
  }, "Load event doesn't fire for removed sheet");
</script>
chromium/third_party/blink/web_tests/external/wpt/css/cssom/HTMLLinkElement-load-event-002.html
