Here it is:
public function makeDropDown($id, $selected = '', $data, $htmlOptions = array(), $action, $chained)
{
$controller=$this->controller;
Yii::app()->clientScript->registerScript('jqcascadeselect'.$id,
"jQuery('#".CHtml::getIdByName($id)."').cascade('#".$chained."',{".
"ajax: {url: 'index.php?r=".$action."'},".
"template: commonTemplate});",
CClientScript::POS_READY);
return CHtml::dropDownList($id, $selected, $data, $htmlOptions);
}