How to append new after current

Example:

$('a').bind('click', function(){
  $('<tr><td>new td</td></tr>').insertAfter($(this).closest('tr'));
});

If you want to create a clone use:

$('a').live('click', function(){
  var $this     = $(this),
      $parentTR = $this.closest('tr');

  $parentTR.clone().insertAfter($parentTR);
});

Example link: http://www.jsfiddle.net/7A6MQ/

Basically, you create a copy from the tr element (which includes child nodes) and insert that copy after that element. Therefore, you need the .live binding to make sure that newly created a elements do also invoke that click handler.

Ref.: .clone(), .insertAfter(), .live()