css/css-scroll-anchoring/contenteditable-near-cursor.tentative.html

<!DOCTYPE html>
<link rel="help" href="https://drafts.csswg.org/css-scroll-anchoring/">
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<style>

body { height: 10000px; }
.content { height: 1000px; background: green; }

</style>


<div id="editable" contenteditable>
  <div id=one class=content>test</div>
  <div id=two class=content>test</div>
  <div id=three class=content>test</div>
  <div id=four class=content>test</div>
  <div id=five class=content>test</div>
  <div id=six class=content>test</div>
</div>

<script>

async_test((t) => {
  editable.focus();

  let range = document.createRange();
  range.setStart(three, 0);
  range.setEnd(three, 1);
  document.getSelection().addRange(range);

  document.scrollingElement.scrollBy(0, 2200);

  t.step(() => assert_equals(document.scrollingElement.scrollTop, 2200, "document prior to content added"));

  requestAnimationFrame(() => {
    let beforeContent = document.createElement("div");
    beforeContent.classList.add("content");

    editable.insertBefore(beforeContent, one);

    t.step(() => assert_equals(document.scrollingElement.scrollTop, 3200, "document content added before"));

    let afterContent = document.createElement("div");
    afterContent.classList.add("content");

    editable.appendChild(afterContent);

    t.step(() => assert_equals(document.scrollingElement.scrollTop, 3200, "document content added after"));
    t.done();
  });
}, "Ensure scroll is adjusted to keep element next to the cursor stable");

</script>