yii 页面加载完成后弹出模态框

<?php
$js = <<<JS
    $('#page-modal').modal('show');//页面加载完显示模态框
    $('.modal-dialog').css('width', '1038px');//设置模态框宽度
JS;
$this->registerJs($js);
use yii\bootstrap\Modal;

Modal::begin([
    'id' => 'page-modal',
    'header' => '<h3 align="center">this is title</h3>',
    'footer' => '<div align="center"><a href="#" align="center" class="btn btn-primary" data-dismiss="modal">好的，我知道了</a></div>',
    'options'=>[
        'data-backdrop'=>'static',//点击空白处不关闭弹窗
        'data-keyboard'=>false,
        'data-show'=>true,
    ],
    'size'=>'modal-lg',
]);

echo "this is content";

Modal::end();
?>

<?= Html::a('点击显示模态框', '#', ['class' => 'btn btn-warning', 'data-toggle' => 'modal', 'data-target' => '#page-modal'])?>