Birthday field is not work with format DD/MM/YYYY in registration page

I have 2 problems with birthday field
1.It's not work with format DD/MM/YYYY in registration page. I set input format is DD/MM/YYYY but it works in MM/DD/YYYY that I dont want it.
2.It's value doesn't keep in session when I refresh the page or go next page and back to this page.

Joomla version 3.3.3
EasySocial version 1.3.4
The page that I found this problem
http://calcoolacademy.com/index.php/community/registration

Thanks a lot for your supports.
Suriya Kaewmungmuang