;
    target3 = document.getElementById("target3");
    target4 = document.getElementById("target4");

    observer = new IntersectionObserver((new_entries) => {
      entries = entries.concat(new_entries);
    });
    observer.observe(target1);
    observer.observe(target2);
    observer.observe(target3);
    observer.observe(target4);

    entries = entries.concat(observer.takeRecords());
    t.step(() => { assert_equals(entries.length, 0, "No initial notifications") });
    requestAnimationFrame(() => {
