Remote Validation or Jquery ajax call shoud in ASP MVC?

Remote Validation or Jquery ajax call shoud in ASP MVC?

I wonder that what is the best method to valid the form in ASP MVC.
I have used Jquery Ajax to check Username exits in my database. So the
problem is when i submit a form, this method need me click to the Username
field to execute onblur function ajax call, it doesn't show previous error
message.
With Remote Validation, it execute when i leave or focus out the Username.
But the problem with this way is i can't manage the error message such as
: The username must be at least 3 charaters.... or The username already
taken.
Anyone can give me a suggestion or some link how to valid a form ontime
(it means when user leave out the field and go ahead to next field, like
this page: http://yame.vn/TaiKhoan/DangKy ) ?