title: how to select multiple values using select2 widget in yii2
body: <p>I am using select to widget in my project and 'multiple' => true</p>
  
  <pre><code> &lt;?php echo $form-&gt;field($model, 'task')-&gt;widget(Select2::classname(), [
                          'data' =&gt; $companiesList,
                          'options' =&gt; ['placeholder' =&gt; 'Select company type ...',],
                          'pluginOptions' =&gt; ['allowClear' =&gt; true,'multiple' =&gt; true,],
                      ]);?&gt;
  </code></pre>
  
  <p>but when I select multiple values it gives error
  <a href="https://i.stack.imgur.com/E1TeF.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/E1TeF.jpg" alt="enter image description here"></a></p>
  
  <p>how to select multiple values using select2??</p>