title: yii2 dependent autocomplete widget
body: <p>I have two fields in a form:</p>
  
  <pre><code>&lt;?= $form-&gt;field($model, 'bill_country')-&gt;widget(AutoComplete::className(), ['options' =&gt; ['class' =&gt; 'form-control'], 'clientOptions' =&gt; ['source' =&gt; $country_name]])-&gt;label('Country') ?&gt;
  &lt;?= $form-&gt;field($model, 'bill_zip')-&gt;widget(AutoComplete::className(), ['options' =&gt; ['class' =&gt; 'form-control'], 'clientOptions' =&gt; ['source' =&gt; '/city/list/+id']])-&gt;label('Zip') ?&gt;
  </code></pre>
  
  <p>Based on the selection of the first block, I want to change the 'source' of the second one. +id is a javascript variable...
  So I vant to get the value of the first autocomplete with val(), assign it to var id, and then pass this id to the source of the second.
  Can I do that?
  Or should I use another option?</p>
  
  <p>Thanks!</p>