<table id="freezedivTable" >
<tr>
<th nowrap="nowrap">序号</th>
<th nowrap="nowrap">内容</th>
</tr>
</table>
alert($('#freezedivTable tr:eq(0) th:eq(0)').html());
<table id="freezedivTable" >
<tr>
<th nowrap="nowrap">序号</th>
<th nowrap="nowrap">内容</th>
</tr>
</table>
alert($('#freezedivTable tr:eq(0) th:eq(0)').html());