Multiselect widget in CQ

Hi

       A multiselect widget is available in extjs 4 http://docs.sencha.com/ext-js/4-1/#!/api/Ext.ux.form.MultiSelect . Is it available in CQ?. I tried taking the same js and customizing it fr CQ, but it didnt work. Is there any way we can customize a same widget for CQ. If anybdy has the customized widget can u share it.

Thanks

Veena