code: public function init()
  	{
  		parent::init();
  		
  		if(!isset($this->options['id'])) {
              $this->options['id'] = $this->getId();
          }
  		
  		if(!isset($this->clientOptions['id'])) {
              $this->clientOptions['id'] = $this->options['id'];
          }
  		
  		if(empty($this->clientOptions['valueNames'])) {
  			throw new InvalidConfigException('The "valueNames" property of "clientOptions" should be set.');
  		}
  		
  		ob_start();
  	}
docs: Initializes the widget.