$form $form : \TbActiveForm Type \TbActiveForm — when created via TbActiveForm. This attribute is set to the form that renders the widget
$asDropDownList $asDropDownList : bool Type bool — whether to display a dropdown select box or use it for tagging
registerClientScript() registerClientScript( $id) ### .registerClientScript() Registers required client script for bootstrap select2. It is not used through bootstrap->registerPlugin in order to attach events if any Parameters $id