Modal

 <!-- Button trigger modal -->
<button type="button" class="btn btn-primary" data-toggle="modal" data-target="#exampleModal">
  Launch demo modal
</button >

<!-- Modal -->
<div class="modal fade" id="exampleModal" tabindex="-1" role="dialog" aria-labelledby="exampleModalLabel" aria-hidden="true">
  <div class="modal-dialog" role="document">
    <div class="modal-content">
      <div class="modal-header">
        <h5 class="modal-title" id="exampleModalLabel">Modal title
        <button type="button" class="close" data-dismiss="modal" aria-label="Close">
          <span aria-hidden="true">× </span>
        </button >
     </div>
      <div class="modal-body">
        ...
     </div>
      <div class="modal-footer">
        <button type="button" class="btn btn-secondary" data-dismiss="modal"> Close</button >
        <button type="button" class="btn btn-primary"> Save changes</button >
      </div>
    </div>
  </div>
</div>

Jquery

 $(function(){
  $('#exampleModal').modal('hide');
  $('#exampleModal').modal('show');
})

ใน yii2 framework จะต้องมี

frontend/views/layout/main.php

     <?php
    NavBar::begin([
        'brandLabel' => "B-Quiz",
        'brandUrl' => Yii::$app->homeUrl,
        'options' =< [
            'clas>s' => 'navbar-inverse navbar-fixed-top',
        ],
    ]);
    $menuItems = [
        ['label' => 'Home', 'url' => ['/site/index']],
        ['label' => 'About', 'url' => ['/site/about']],
        ['label' => 'Contact', 'url' => ['/site/contact']],
    ];
    if (Yii::$app->user->isGuest) {
        $menuItems[] = ['label' => 'Signup', 'url' => ['/site/signup']];
        $menuItems[] = ['label' => 'Login', 'url' => ['/site/login']];
    } else {
        $menuItems[] = '<li>'
            . Html::beginForm(['/site/logout'], 'post')
            . Html::submitButton(
                'Logout (' . Yii::$app->user->identity->username . ')',
                ['class' => 'btn btn-link logout']
            )
            . Html::endForm()
            . '</li>';
    }
    echo Nav::widget([
        'options' => ['class' => 'navbar-nav navbar-right'],
        'items' => $menuItems,
    ]);
    NavBar::end();
    ?>