Nothing output to my Webbrowser?

[eluser]huaxz1986[/eluser]
I just insert a php sentence, and data configure is OK.However,nothing output in my Webbrowser.I checked err.log of MYSQL, no errors.I checked err.log of apache2 too,and no errors as well.

class Welcome extends CI_Controller {
public function index()
{
$this->load->database();
$this->load->view(‘welcome_message’);
}
}