Topic: printing using javascript

Hello,
I am trying to print using javascript and have run into a snag.  Currently I am using:

<%= link_to 'Print PDD', { :action => 'show', :id => @pdd.id} , :onClick=>"parent.print()"  %>
to handle the printing.  This works fairly well, but I am getting more than I actually want to print.  I only want the information being diplayed by my partial view (_showForm.rhtml) to be printed.  However, I am getting everything that is on the show.rthml (which render the partial of _showForm.rhtml) view as well.  Does anybody know how to make it only print the partial?

Thank you,
David