How to valalidation custom type data ?

[eluser]pisio[/eluser]
Hi all.
How I can use $this->form_validation->set_rules to check custom cata fild ?
Data => d/m/Y = > 19/08/1991 ....
sorry for my bad english...

[eluser]WanWizard[/eluser]
Check the section in the user guide discussing form validation callbacks...

[eluser]pisio[/eluser]
[quote author="WanWizard" date="1281647009"]Check the section in the user guide discussing form validation callbacks...[/quote]10x