t checks a dynamically added 'column-span' element should be rendered correctly.">

  <script>
  function runTest() {
    document.body.offsetHeight;

    /* Add the spanner in block1. It should correctly span across all columns. */
    var spanner = document.createElement("h3");
    var text = document.createTextNode("spanner");
    spanner.appendChild(text);

    var block1 = document.getElementById("block1");
    block1.appendChild(spanner);

    document.documentElement.removeAttribute("class");
  }
  <