php - Accessing controller's global variable in ajax returns NULL -

hi guys have controller proceses data in index() assign on global variable.

i want global variable accessed ajax when pages loaded.

here i've done in index():

class search extends ss_controller {   public static $q;      public function index(){          $k = $this->input->get(null, true);          $data['title'] = "search";         $data['page_content'] = "search_results_view.php";         $data['logout'] = "/./ssmis/home/logout";         $data['active_nav'] = 'search';         $data['k'] = $k['k'];          self::$q = array('123','456');         ... 

and have method function called in ajax:

 public function q(){          var_dump(self::$q );          if(self::$q ){             $response['error'] = false;             $response['has_data'] = true;             $response['message'] = 'success';             $response['data'] = $this->q;              $this->echo_response($response,200,'ok!');         } else {             $response['error'] = true;             $response['message'] = 'no results returned';               $this->echo_response($response,200,'not ok!');         }     } 

the problem var_dump(self::$q ); returns null.

how can value of $q assigned in index() of controller?

thanks!

you're mixing terms. in code $q class static variable, not global variable - defined using keyword global before var name, e.g. global $foo. note: using global in 2015 very bad idea™ - not this.

secondly, don't seem understand how request-response works. if call index method sets variable, once script completes execution, self::$q no longer exists. ajax request isn't pixie dust, it's regular http request - new request. brand-new request route calls q() not have called index() before, no code setting self::$q ever executed, ajax request's point of view. in other words, variable set on course of single request exists until request has returned response. if want persist, need store value of $q in form of persistent storage - database, user's session, cookies or that.