Why i need to put evrything in a index function

[eluser]ramm[/eluser]
[quote author="Achmed1" date="1306004746"]Thanks for the info, But example i got a form with <?php echo form_open('index.php/register/validation'); ?> i need to put all the fucntions in the validation function ?[/quote]

Yes, for that example you will have a controller called "register.php" with a function called "validation".

It is everything here: http://ellislab.com/codeigniter/user-guide/