[jQuery] Duplicating the last row of a table

[jQuery] Duplicating the last row of a table

<html>
<body>
<tt>Hello folks,
The code and HTML below are from a quiz editor - I have an onClick
function that fires duplicateRow to add another question box onto the end
of the table.
Firefox does what I expect to happen - it selects the last <tr>
row.  IE7 and Safari, on the other hand, appear to treat the
<tfoot> as the last tr in the table. 
Is there a way to satisfy the interpretation of all three
browsers?
Thanks,
Bruce
function duplicateRow(){
        var clonedRow =
$("#question_table tr:last").clone();
        var iRowID = 
parseFloat(clonedRow.attr("id").replace('t',''));
        iNewID = iRowID + 1;
        $("#bc"+ iRowID ,
clonedRow).attr( { "id" : "bc" +
iNewID,"name" : "correctans" + iNewID,
"checked":false } );
        $("#lba"+ iRowID ,
clonedRow).attr( { "id" : "lba" +
iNewID,"for" : "theans" + iNewID } );
        $("#lbb"+ iRowID ,
clonedRow).attr( { "id" : "lbb" +
iNewID,"for" : "bc" + iNewID } );
        $("#lbc"+ iRowID ,
clonedRow).attr( { "id" : "lbc" +
iNewID,"for" : "fb" + iNewID } );
        $("#sL"+ iRowID ,
clonedRow).attr( { "id" : "sL" + iNewID} );
        $("#fb"+ iRowID ,
clonedRow).attr( { "id" : "fb" +
iNewID,"name" : "feedback" + iNewID,
"value":"" } );
        $("#theans"+ iRowID
, clonedRow).attr( { "id" : "theans" +
iNewID,"name" : "answer" + iNewID,
"value":""} );
       
$("#question_table").append(clonedRow);
        $("#question_table
tr:last").attr( "id", "t" + iNewID);
       
$("#sL"+iNewID).html("Answer
"+parseFloat(iNewID+1));
       
$("#noptions").attr({"value":iNewID});
};
</tt><pre><tr id="t4" class="qdot"><td
colspan="2">

<label class="label7"
id="lba4" for="theans4"><span
id="sL4">Answer 5</span></label><textarea
rows="3" id="theans4" name="answer4"
class="qinput30">lateral buds
only</textarea>




<label
class="label7" for="bc4"
id="lbb4">Correct?</label><input
name="correctans4" id="bc4" value="1"
type="checkbox">



<label
id="lbc4" class="label7"
for="fb4">Feedback
(standard)</label><textarea
rows="3" name="feedback4" id="fb4"
class="qinput30">while they do occur in axillary/lateral
buds, they also occur at terminal
buds</textarea>






</td></tr></tbody><tfoot><td
class="strong smfont90"><a href="#"
onclick="duplicateRow();return false;" title="Add more
options to this question"><img src="images/add.png"
class="timg" alt="Add more options"
width="16" height="16"></a> Add more
possible answers</td></tfoot></table>
</body>
</html>