required in codeigniter code example
Example 1: codeigniter form_validation email
$this->form_validation->set_rules('email', 'Email', 'trim|required|valid_email');
Example 2: codeigniter validation text length
$this->form_validation->set_rules('ratingMessage', 'Review message', 'trim|max_length[255]|max_length[10]');
$this->form_validation->set_message('max_length', 'Message you have entered for %s is too long please try again!');