GridView и CheckBoxColumn

Обработка выделения объектов в таблице:

<script type="text/javascript">
    $(document).ready(function(){
        $("input[type=checkbox]").click(function(){
            var keys = $('#usergrid').yiiGridView('getSelectedRows');
            alert(keys);
        });
    });
</script>

<div class="user-index">

<h1><?= Html::encode($this->title) ?></h1>
<?php // echo $this->render('_search', ['model' => $searchModel]); ?>

<?php Pjax::begin(); ?>
<?= GridView::widget([
        'id'=>'usergrid',
        'dataProvider' => $dataProvider,
        'filterModel' => $searchModel,
        'columns' => [
            ['class' => 'yii\grid\SerialColumn'],
            [
                'class' => 'yii\grid\CheckboxColumn',
                'checkboxOptions' => function ($model, $key, $index, $column) {
                    return ['value' => $model->user_id];
                }
            ],
            'user_id',
            'user_login',
            'user_pass',
            'user_name',
            'user_active',

            ['class' => 'yii\grid\ActionColumn'],
        ],
]); ?>
<?php Pjax::end(); ?>
</div>