gistfile1.rb

  def mobile?
    if session[:mobile_param]
        session[:mobile_param] == "1"
      else
        request.user_agent =~ /Mobile|webOS/
      end
  end
  
  helper_method :mobile?
  
  def mobile_format
    session[:mobile_param] = params[:mobile] if params[:mobile]
    
    if mobile?
      if request.format == :js
        request.format = :mobilejs
      else
        request.format = :mobile
      end
    end
  end