Ajax calls on Submit-based validation are optional

The 'ajaxOnSubmit' option on JFormer can be used to specify whether
or not ajax-based validation options (such as 'serverSide') are
executed when validating a page / all pages upon clicking a submit
button.

The default is true (meaning ajax calls will be made).
Options prefixed with '__' are not sent to client

Otions values that might contain sensitive information can now use
a prefix of '__' on the option name to prevent the value from being
sent to clients.

Note: Options prefixed with '__' are not special-cased on the server
and server-side code will need to refer directly to the prefixed name
to make use of these variables.
Also, the option names are still sent to the client, please be careful
if those option names contain sensitive information as well.