When I select a row and append to each row as follows, only the contents of the cell get appended.

$(document).ready( function() {

$("TR").append("<TD>4</TD>");

});

Results in the HTML

<tr>

<td>1</td>

<td>2</td>

<td>3</td>

4</tr>

Obviously I was expecting

<tr>

<td>1</td>

<td>2</td>

<td>3</td>

<td>4</td>

</tr>