chromium/third_party/blink/web_tests/external/wpt/css/css-multicol/table/table-cell-content-change-000.html

<!DOCTYPE html>
<link rel="help" href="https://bugs.chromium.org/p/chromium/issues/detail?id=348064">
<link rel="match" href="table-cell-content-change-000-ref.html">
<p>You should see the text "first column" once in the first column, and the text
  "second column" twice in the second column.</p>
<div style="columns:2; orphans:1; widows:1;">
  <div style="display:table-row;">
    first column
    <div style="height:0.1em;"></div>
  </div>
  <div style="display:table-row;">
    second column
    <div id="elm" style="display:none;">second column</div>
  </div>
</div>
</body>
<script>
  document.body.offsetTop; // trigger layout
  document.getElementById('elm').style.display = 'block';
</script>