css/cssom-view/offsetTopLeft-table-caption.html

<!doctype html>
<meta charset="utf-8">
<link rel="help" href="https://drafts.csswg.org/cssom-view/#dom-htmlelement-offsetparent">
<title>offset* APIs on tables with captions.</title>
<script src=/resources/testharness.js></script>
<script src=/resources/testharnessreport.js></script>
<table style="border-spacing: 0px">
 <caption>I'm a <br>reasonably<br>tall caption.</caption>
 <tr><td><span>I'm a cell.</span>
</table>
<script>
  let td = document.querySelector("td");
  let span = document.querySelector("span");
  let caption = document.querySelector("caption");
  let table = document.querySelector("table");
  test(function() {
    assert_equals(span.offsetParent, td, "<td> should be an offset parent");
    assert_equals(td.offsetParent, table, "<table> should be an offset parent for <td>");
    assert_equals(caption.offsetParent, table, "<table> should be an offset parent for <caption>");
    assert_equals(caption.offsetTop, 0, "<caption> is at the top of its offsetParent");
    assert_equals(td.offsetTop, caption.offsetHeight, "<td> is under the caption");
  });
</script>