validation problem

[eluser]dimis[/eluser]
I want to see if a text input is empty when a condition exists.
So I extend validation and write this function.

Code:

function _check_text($str,$type)
    {
        
       if (empty($str) && $type['item']==$type['value'] )
        {
            $this->set_message('_check_text',"You must fill .");
            return FALSE;

       }
       return TRUE;
    }

But it does not work.How can I find if the value of the input is empty?
Dimis