php - yii2 ActiveForm field placeholder -

i want create form using yii2 activeform. here code:

<?php $form = \yii\widgets\activeform::begin([     'options' => [         'class' => 'form-inline'         ] ]); ?> <div class="form-group">      <label class="sr-only" for="example">email</label>      <?php echo $form->field($model, 'email', [            'inputoptions' => ['autofocus' => 'autofocus', 'class' => 'form-control transparent']      ])->textinput(['placeholder' => "enter email"])->input('email')->label(false); ?> </div>   <button type="submit" class="subscr-btn btn btn-primary btn-fill">join</button> <?php \yii\widgets\activeform::end(); ?> 

which generates html:

<form id="w0" class="form-inline" action="/example" method="post"> <div class="form-group">     <label class="sr-only" for="exampleinputemail2">email address</label>     <div class="form-group field-subscriber-email required">         <input type="email" id="subscriber-email" class="form-control transparent" name="subscriber[email]"                autofocus="autofocus">         <div class="help-block"></div>     </div> </div> <button type="submit" class="subscr-btn btn btn-primary btn-fill">join</button> 

everything ok, placeholder?

put inside input() method second parameter - reference

<div class="form-group">      <label class="sr-only" for="example">email</label>      <?php echo $form->field($model, 'email', [            'inputoptions' => ['autofocus' => 'autofocus', 'class' => 'form-control transparent']      ])->textinput()->input('email', ['placeholder' => "enter email"])->label(false); ?> </div>