css/css-tables/dynamic-rowspan-change.html

<!doctype html>
<script src='/resources/testharness.js'></script>
<script src='/resources/testharnessreport.js'></script>
<script src='/resources/check-layout-th.js'></script>
<link rel="author" href="mailto:atotic@chromium.org">
<link rel="help" href="https://html.spec.whatwg.org/multipage/tables.html#the-td-element">
<meta name="assert" content="Dynamic changes to rowspan/colspan relayout the table" />
<style>
  main table {
    border-spacing:0;
  }
  main td {
    background: green;
    width:50px;
    height:50px;
    padding: 0;
  }
</style>

<main>
  <table data-expected-width="100">
    <tr>
      <td id="rowspan_target"></td>
    </tr>
    <tr>
      <td></td>
    </tr>
  </table>
<br>
  <table data-expected-width="150">
    <col style="width:50px">
    <col style="width:50px">
    <tr>
      <td id="colspan_target"></td>
      <td></td>
    </tr>
  </table>
</main>

<script>
  document.body.offsetTop;
  document.querySelector("#rowspan_target").setAttribute("rowspan", "2");
  document.querySelector("#colspan_target").setAttribute("colspan", "2");
  checkLayout("main table");
</script>