EOT; $form = sprintf($formTemplate, home_url('/'), // %1$s action get_search_query(), // %2$s query __('Search', 'toebox-basic')) // %3$s button caption ; return $form; }); add_filter('nav_menu_walker_arguments', function ($arguments) { $searchForm = sprintf('%s', get_search_form(false)); $arguments['items_wrap'] = str_ireplace('', $searchForm, $arguments['items_wrap']); return $arguments; }, 0, 1);