how to find parent ID?

how to find parent ID?

I know this might seem like a newb question,

but the following returns nothing for me, except a blank alert box...

  2. $('.editPt').click(function(){
  3. alert( $(this).parent().id );   
  4.      });
here is the HTML 

  1. <tr id='tr_1'> <td id='td_1' title=id class='editPt' > 0</td> <td id='td_2' title=mrno>17730</td> <td id='td_3' title=Patient></td> <td id='td_4' title=ptType>heme</td>
    </tr> 
    etc....

Thanks for any help in advance!

jQuery Newb