php - Undefined property: CI_Loader::$input

I've just started to learn CodeIgniter and gotten trouble with example below:
My Controller:

      class Site extends CI_Controller 
      {
        public function __construct()
    {
parent::__construct();
    }
    function index()
    {
    $this->load->view('options_view');
    }
        function create()

    {
    $data = array (
     'title' => $this->load->input->post('title'),
     'content' => $this->load->input->post('content')
    );
     $this->site_model->add_record($data);
     $this->index();
    }
      }
   

My Model is:

    class Site_model extends CI_Model
    {
     function get_records()
     {
     $q = $this->db->get('articles');
     return $q->result();
     }
    function add_record($data)

     { 
      $this->db->insert('articles',$data);
      return;
     }
    }

My view is:

       
    

      Title:
      
    
     

      Content: 
       
      
      


       
      
      

So when I click Submit button I get the error like:

Severity: Notice
Message: Undefined property: CI_Loader::$input

Filename: controllers/site.php
Line Number: 19


Any ideas will be usefull!Thanx!!