OK, this is an embarrassingly simple question. Why doesn't the following jQuery example work? Obviously it is supposed to change the 'a' in the table to 'hello'.
HTML code:
<table id='table1'>
<tr>
<td>a</td>
<td>b</td>
</tr>
</table>
JavaScript (JQuery) code:
$("#table1 td:contains('a')").innerHTML="hello";