title: Yii2 disabled textInput ActiveForm
body: <p>how to disabled textInput in ActiveForm ?
  i try like this but can't</p>
  
  <pre><code>&lt;?= $form-&gt;field($model, 'title_series')-&gt;textInput(['class' =&gt; 'form-control class-content-title_series', 'placeholder' =&gt; 'Title', 'disabled' =&gt; 'disabled'])-&gt;label(false) ?&gt;
  </code></pre>
  
  <p>'disabled' => 'disabled or 'disabled' => true
  both of them can't too</p>