<script type="text/javascript">
$(document).ready(function() {


    $('#description').show();
    $('#extender').click(function() {
    $('#description').slideToggle("fast");

    });

});
</script>

 <tr>
    <td>cell1</td>
    <td><a href="#" id="extender">link</a></td>
  </tr>
  <tr id="description">
    <td colspan="2" class="desc">This should span two columns but it doesnt bla jaajja</td>
  </tr>
  <tr>
    <td>cell1</td>
    <td>cell2</td>
  </tr>

var el = $("TR.post_"+_id+' TD');
       el.wrapInner("<div/>");
       $("TR.post_"+_id+' TD DIV').slideUp('500');
       setTimeout(function(){el.remove()},500);