using jquery how do alter the css of the last tr with a th

```
$("#mytable tr").has('th').last().parents('tr').css({'color':'blue'});

```

HTML 

```
<table border="1" id="mytable">
    <tr>
        <th>row 1, cell 1</th>
        <th>row 1, cell 2</th> 
    </tr>
    <tr> 
        <th>row 1, cell 1 - change this</th>
        <th>row 1, cell 2 - change this</th> 
    </tr>
    <tr>
        <td>row 2, cell 1</td>
        <td>row 2, cell 2</td>
    </tr>
</table>

```