PhP forms in CodeIgniter

[eluser]Unknown[/eluser]
Hi its my first time using Code Igniter and I am trying to get data from a form using.

Code:

$varUser = $this->input->post('loginName');              
              
                
echo  $varUser;

in my controller when I echo the variable, the page is blank.

the function is working as i echoed a hello world and it worked

has anyone get any ideas why it isn't working.