View

<?php
/* @var $this yii\web\View */
use yii\widgets\ActiveForm;
?>

<?php $form = ActiveForm::begin(['id' => uniqid()]); ?>

<?php $form->enableAjaxValidation = true;?>

<?= $form->field($model, 'name', [
    /* Опции template, selectors, options изменены для соответствия сторонней верстке */
    'template' => '
       <div class="form-callback-name field half first">
           {input}
           {error}
       </div>
       ',
    'selectors' => [
        'container' => '.form-callback-name.field',
        'input' => '.form-callback-name input',
        'error' => '.form-callback-name .help-block',

    ],
    'options' => [
        'tag' => null, // Don't wrap with "form-group" div
    ],
    'inputOptions' => [
        'placeholder' => 'Имя',
    ]
])->textInput(['maxlength' => true]) ?>

<?= $form->field($model, 'email', [
    'template' => '
       <div class="form-callback-email field half">
           {input}
           {error}
       </div>
       ',
    'selectors' => [
        'container' => '.form-callback-email.field',
        'input' => '.form-callback-email input',
        'error' => '.form-callback-email .help-block',

    ],
    'options' => [
        'tag' => null, // Don't wrap with "form-group" div
    ],
    'inputOptions' => [
        'placeholder' => 'E-mail',
    ]
])->textInput(['maxlength' => true]) ?>

<?= $form->field($model, 'comment', [
    'template' => '
       <div class="form-callback-comment field">
           {input}
           {error}
       </div>
       ',
    'selectors' => [
        'container' => '.form-callback-comment.field',
        'input' => '.form-callback-comment textarea',
        'error' => '.form-callback-comment .help-block',

    ],
    'options' => [
        'tag' => null, // Don't wrap with "form-group" div
    ],
    'inputOptions' => [
        'placeholder' => 'Сообщение',
    ]
])->textarea(['rows' => 2]) ?>

<ul class="actions">
    <li><input type="submit" value="Отправить" class="special" /></li>
</ul>

<?php ActiveForm::end(); ?>