Codeigniter: How can i encrypt password before submitting the form to the controller?

Question

I have a simple html login form

Answer 1

$password = sha1($this->input->post('password'));

or 

$hash= $this->input->post('password');

$password= $this->encrypt->sha1($hash);

you can use md5 instead of sha1 but sha1 is more secure then md5... and both md5 & sha1 are non-decodable