The JavaScript form validation does not work

When you have a subscription form, before WordPress 3.6, you could see some error messages when people didn’t fill their email properly.

But now, with WordPress 3.6, when you leave blank the email field in a form and you click on the submit button of the form, you are redirected to this URL:
http://www.yourdomain.com/#wysija
and the form keeps “thinking”.

The error messages appear in a different position, and they are not the same messages…

Thanks a lot for your help.

http://wordpress.org/plugins/wysija-newsletters/