how can redirect with validate

[eluser]Kency[/eluser]
[quote author="berkguy" date="1338447337"]You mean the callback when you use the CI form validation?[/quote]

ok i post sample code to make sense what i mean

Code:

url: http://example.com/form

<?php

form_open("controller/checkform);
//content
form_close();

?>

and my controller

Code:

function checkform(){
$this->load->library("form_validation");
            //some rule for validate
            if($this->form_validation->run()==FALSE){
                $this->form()
}

url change from http://example.com/form to http://example.com/checkform

but i dont want my url change like that, if i use redirect(/form) my form doesn't show any error