Functions

// Subpage Shortcode
function is_child($page_id_or_slug) {
    global $post;
    if(!is_int($page_id_or_slug)) {
        $page = get_page_by_path($page_id_or_slug);
        $page_id_or_slug = $page->ID;
    }
    if(is_page() && $post->post_parent == $page_id_or_slug ) {
            return true;
    } else {
            return false;
    }
}