public function _js_vars() {
		$args = array(
			'class'  => get_class( $this ),
			'screen' => array(
				'id'   => $this->screen->id,
				'base' => $this->screen->base,
			)
		);

		printf( "<script type='text/javascript'>list_args = %s;</script>\n", PUM_Utils_Array::safe_json_encode( $args ) );
	}