ajax validation in CI with 'jQuery validation plugin'

[eluser]PhilTem[/eluser]
You receive a different error message than a "page not found". What you get is an internal server error

NetworkError: 500 Internal Server Error

In most cases this happens when you have some line of code that makes your sever go like "ermahgerd".
I think the problem causing line(s) are somewhere else because your posted lines look pretty good and faultless. Though there might be an error emerging from

Code:

if (array_key_exists('benutzername', $_POST)) {

Try changing it to

Code:

if ( $this->input->post('benutzername') ) {

and see if it works.