<!DOCTYPE html>
<html>
  <head>
    <script language="javascript">
      function toggleRow(rowId)
      {
        var r = document.getElementById(rowId);
        if (r.style.display == "none")
          r.style.display = "inline";
        else
          r.style.display = "none";
      }

      function doTest() {
        toggleRow('row4');
        document.body.offsetWidth;
        toggleRow('row4');
        document.body.offsetWidth;
        toggleRow('row4');
        document.body.offsetWidth;
        toggleRow('row4');
        document.body.offsetWidth;
        toggleRow('row4');
        document.body.offsetWidth;
        toggleRow('row4');
        document.body.offsetWidth;
        toggleRow('row4');
        document.body.offsetWidth;
        toggleRow('row4');
        document.body.offsetWidth;
        toggleRow('row4');
      }
    </script>
  </head>
  <body onload="doTest()">
    <table border="5">
      <tr>
        <td>Row 1</td>
      </tr>
      <tr>
        <td>Row 2</td>
      </tr>
      <tr>
        <td>Row 3</td>
      </tr>
      <tr id="row4" style="display: none">
        <td>Row 4</td>
      </tr>
    </table>
  </body>
</html>