I testing IE 11 preview (win7)
<!DOCTYPE html><html><head><script>
function displayResult()
{
alert(document.getElementById("myTable").rows.length);
}</script></head><body><table id="myTable" border="1" style='posit.ion:relative;padding-top:30px;'><thead style='posit.ion:absolute;top:0px;left:0px;'><tr><td>cell 1</td><td>cell 2</td></tr></thead><tbody><tr><td>cell 3</td><td>cell 4</td></tr></tbody></table><br><button type="button" onclick="displayResult()">Test rows</button></body></html>Please: posit.ion replace to position :-) (text not akceptet 'position')
In function displayResult() testing param rows.
If thead section is position absolute, rows ignore first line in table.