datetime - date time picker bootstrap -

i'm developing application have create date time picker users,but problem i'm using bootstrap date time picker here:- for date time picker giving me bydefault time.its 12 hours ahead form local time should this. if u have idea on method please suggest me.

and question i'm trying converting user's time date utc time using this:-$datetime1=gmdate("y-m-d h:i:s", strtotime($datetime)); , not converting correct utc time.please suggest me have do.

the locale value datetimepicker on link provided language: 'pt-br'. change 'en-us' or other valid value to achieve correct timezone datetime.