TbHtml::dropDownList PHP Method

    public static function dropDownList($name, $select, $data, $htmlOptions = array())
    {
        $displaySize = TbArray::popValue('displaySize', $htmlOptions);
        // In case we do need to create a div container for the input element (i.e. has addon or defined col)
        $containerOptions = array();
        // Get the intended input width before the rest of the options are normalized
        self::addSpanClass($htmlOptions);
        self::addColClass($htmlOptions);
        $col = self::popColClasses($htmlOptions);
        $htmlOptions = self::normalizeInputOptions($htmlOptions);
        self::addCssClass('form-control', $htmlOptions);
        if (!empty($displaySize)) {
            $htmlOptions['size'] = $displaySize;
        }
        if (!empty($col)) {
            self::addCssClass($col, $containerOptions);
        }
        $output = '';
        if (!empty($containerOptions)) {
            $output .= self::openTag('div', $containerOptions);
        }
        $output .= parent::dropDownList($name, $select, $data, $htmlOptions);
        if (!empty($containerOptions)) {
            $output .= '</div>';
        }
        return $output;
    }

 /**
  * Runs the widget.
  */
 public function run()
 {
     list($name, $id) = $this->resolveNameID();
     $id = $this->resolveId($id);
     echo TbHtml::openTag('div', array('class' => 'select2'));
     if ($this->hasModel()) {
         if ($this->asDropDownList) {
             echo TbHtml::activeDropDownList($this->model, $this->attribute, $this->data, $this->htmlOptions);
         } else {
             echo TbHtml::activeHiddenField($this->model, $this->attribute, $this->htmlOptions);
         }
     } else {
         if ($this->asDropDownList) {
             echo TbHtml::dropDownList($name, $this->value, $this->data, $this->htmlOptions);
         } else {
             echo TbHtml::hiddenField($name, $this->value, $this->htmlOptions);
         }
     }
     echo '</div>';
     if ($this->assetPath !== false) {
         $this->publishAssets($this->assetPath);
         $this->registerCssFile('/select2.css');
         if ($this->registerJs) {
             $this->registerScriptFile('/select2.js', CClientScript::POS_END);
         }
     }
     if ($this->bindPlugin) {
         $options = !empty($this->pluginOptions) ? CJavaScript::encode($this->pluginOptions) : '';
         $this->getClientScript()->registerScript(__CLASS__ . '#' . $id, "jQuery('#{$id}').select2({$options});");
     }
 }