add_shortcode('field', 'shortcode_field'); function shortcode_field($atts){ extract(shortcode_atts(array( 'post_id' => NULL, ), $atts)); if(!isset($atts[0])) return; $field = esc_attr($atts[0]); global $post; $post_id = (NULL === $post_id) ? $post->ID : $post_id; return get_post_meta($post_id, $field, true); }