Codeigniter Ajax Datatable showing Error -

i have referred link make codeigniter datatable ajax based datatable.

http://mbahcoding.com/tutorial/php/codeigniter/codeigniter-simple-server-side-datatable-example.html

but showing error , not showing data in datatable.

message: undefined index: length

message: undefined index: start

message: undefined index: draw

please me remove these errors.

my jquery

$(document).ready(function(){       //ajax datatable       //datatables     var datatable = $('#datatables-suburb').datatable({           processing: true, //feature control processing indicator.         serverside: true, //feature control datatables' server-side processing mode.         order: [], //initial no order.          // load data table's content ajax source         ajax: {             url: "<?php echo site_url('admin/states/state_table_ajax')?>",             type: "post"         },          //set column definition initialisation properties.         columndefs: [         {              targets: [ 0 ], //first column / numbering column             orderable: false, //set not orderable         },         ],       });   });  

my controller function

public function state_table_ajax()     {        $data['details'] = $this->loginmodel->admin_details($this->session->userdata('admin-username'));        foreach($data['details'] $detail):        $country_id = $detail['country_id'];     endforeach;         $states = $this->statesmodel->get_states_table($country_id);          $no = $_post['start'];          foreach($states $state):             $no++;             $row = array();             $row[] = $no;             $row[] = $state['id'];             $row[] = $state['state_name'];             //$row[] = '<button type="button" name="update" id="'.$state['id'].'" class="btn btn-warning btn-xs">update</button>';               //$row[] = '<button type="button" name="delete" id="'.$state['id'].'" class="btn btn-danger btn-xs">delete</button>';               $state_data[] = $row;         endforeach;          $output = array(                 "draw" => $_post['draw'],                 "recordstotal" => $this->statesmodel->get_states_count($country_id),                 "recordsfiltered" => $this->statesmodel->get_states_count_filtered($country_id),                 "data" => $state_data,         );         //echo "<pre>";         //print_r($output);         //output json format         echo json_encode($output);     } 

my model code

public function get_states($country_id)     {         $order_column = array('id', 'state_name');         $this->db->select('id, state_name')                            ->where('country_id', $country_id, false)                            ->from('tbl_states');          //for search value datatable         if(isset($_post['search']['value']))          {             $this->db->like('state_name', $_post['search']['value']);         }         //for order datatable         if(isset($_post['order']))         {             $this->db->order_by($this->order_column[$_post['order']['0']['column']], $_post['order']['0']['dir']);         }         else           {               $this->db->order_by('id', 'desc');           }          //$result = $query->result_array();         //return $result;     }     //get datatable     public function get_states_table($country_id)     {         $this->get_states($country_id);         if($_post["length"] != -1)         {             $this->db->limit($_post["length"], $_post["start"]);             $query = $this->db->where('country_id', $country_id, false)                               ->get();             return $query->result_array();         }     }     function get_states_count_filtered($country_id)     {         $this->get_states($country_id);         $query = $this->db->where('country_id', $country_id, false)                           ->get();         return $query->num_rows();     }     public function get_states_count($country_id)       {          $this->db->where('country_id', $country_id, false)                 ->from('tbl_states');           return $this->db->count_all_results();     }  

thank in advance.

in controller

from

$no = $_post['start']; 

to

if(isset($_post['start']) && isset($_post['draw'])) {      $no = $_post['start']; }else{      // need start , draw       die(); // error  } 

and in model

from

if($_post["length"] != -1) 

to

if(isset($_post["length"]) && $_post["length"] != -1)