How to use global variable in PHP Codeigniter - php

Question

I have implemented the login logic in an MVC application; I want to see if the user has filled the username and passowrd incorrectly and if so I want to show a notifictaion in the view; so I'm passing this information via $data['er']; but for some reason it is not catching this data:
Please let me know if my question is clear or not; and if any clarification is needed, please let me know which part is ambiguous
My code:
class Login extends CI_Controller {
public function __construct() {
parent::__construct();
$GLOBALS['er'] = False;
}
public function index() {
$data['er']=$GLOBALS['er'];
$data['main_content'] = 'login_form';
$this->load->view('includes/template', $data);
}
public function validate_credentials() {
$this->load->model('user_model');
$query = $this->user_model->validate();
if ($query) {
$data = array(
'username' => $this->input->post('username'),
);
$this->session->set_userdata($data);
redirect('project/members_area');
} else {
$GLOBALS['er'] = TRUE;
$this->index();
}
}
}

Answer 1

Don't use GLOBALS you can just use a private variable in your class.
Create the variable above your __construct function like private $er
In your __contruct function set the default value
Set and get in your public function using $this->er
Implemented in your code:
class Login extends CI_Controller {
private $er;
public function __construct() {
parent::__construct();
$this->er = FALSE;
}
public function index() {
$data['er']= $this->er;
$data['main_content'] = 'login_form';
$this->load->view('includes/template', $data);
}
public function validate_credentials() {
$this->load->model('user_model');
$query = $this->user_model->validate();
if ($query) {
$data = array(
'username' => $this->input->post('username'),
);
$this->session->set_userdata($data);
redirect('pmpBulletin/members_area');
//die(here);
} else {
$this->er = TRUE;
$this->index();
}
}
}