Rails - Apr 2009 - will the controller compiles the rjs only on ajax request ?

will the controller compiles the rjs only on ajax request ?

class xyzController < .....
 def ajax_req
    ""This works fine ""
    """ajax_req.rjs is not compiled"""
 end
 def non_ajax_req
    """ non_ajax_req.rjs is not compiled"""
 end
end

Am i right or my code lacks something ?