public function actionIndex()
{
$filterModel = new Book();
if (Yii::$app->request->get('Book')) {
$filterModel->load(Yii::$app->request->get());
}
$getArray = Yii::$app->request->get();
$getArray['Book'] = $filterModel->getArrayForLink();
$this->_registerJs();
return $this->render('index', ['dataProvider' => $filterModel->search(), 'filterModel' => $filterModel, 'authors' => Author::find()->all(), 'getArray' => $getArray]);
}