JavaScript How to show message in view & replace a div using ajax in codeigniter? show message in view mvc,show message in view laravel,

I am stuck with ajax... I have a cart and it has gift vouchers, i) the code checks for valid voucher and if its not valid then it should show message "invalid voucher". ii) If voucher if valid and is set in db,then change the cart total using gift amount.

So I have set the message , but i dont know how to dislay it.And Using gift i have stored the new cart total ie gift_cart_total.In db, i have fields for cart_total,voucher , gift_cart_total.How can i remove my original cart div and show new div using gift_cart_total.

View:

<div class="giftvoucher">
   <input type="text" name="gift_voucher_number" id="gift_voucher_number" placeholder="Voucher Number" value="" size=18>
   <input type="text" name="gift_voucher_pin" id="gift_voucher_pin" placeholder="Voucher Pin" value=""size=18>
   <input type="button" value="Apply" onclick="checkGiftVoucher()" id="apply_button">
</div>
<script type="text/javascript">
function checkGiftVoucher(){
    var gift_voucher_number = $("#gift_voucher_number").val();
    var gift_voucher_pin = $("#gift_voucher_pin").val();

    $.ajax({
         type: "POST",
         url: "<?php echo base_url('cart/giftvalidate'); ?>",
         data: {gift_voucher_number:gift_voucher_number,gift_voucher_pin:gift_voucher_pin} , 

          success: function(data){
             return false;

         },
        });
  }

   </script> 

Controller:

public function giftvalidate(){
    if(isset($_POST['gift_voucher_number']) && $_POST['gift_voucher_number'] != '' && isset($_POST['gift_voucher_pin']) && $_POST['gift_voucher_pin'] != ''){           
        $app21_url      = APP21_URL;
        $country_code   = COUNTRY_CODE;

        $gift_voucher_number    = $_POST['gift_voucher_number'];
        $gift_voucher_pin   = $_POST['gift_voucher_pin'];

        $result         = $this->cart_model->checkValidGift($gift_voucher_number, $gift_voucher_pin, $app21_url, $country_code);
        if($result['databool'] && !empty($result['dataValue'])){

            $discount   = $result['dataValue']['AvailableAmount'];
        }else{

            $gift_flash = $result['datamsg'];
        }

    }elseif(isset($_POST['gift_voucher_number']) && (empty($_POST['gift_voucher_pin']) || $_POST['gift_voucher_pin'] =='')){            
        $result['datamsg']  = "Please enter the gift voucher pin";  
    }

    echo json_encode($result);
}

Model :

function checkValidGift($gift, $gift_pin, $app21_url, $country_code){

    $returndata = array();
    $dataValue  = array();
    $datamsg    = '';
    $databool   = false;
    $cartTotal  = $this->getTotalCart();
    $GVValid_url = some url here;

    $headers = array(
        "GET HTTP/1.1",
        "Content-type: text/xml",
        "Accept: Version_2.0"
    );

    $ch = curl_init();
    curl_setopt($ch, CURLOPT_URL, $GVValid_url);
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
    curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, 0);
    curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, 0);
    curl_setopt($ch, CURLOPT_TIMEOUT, 900);
    curl_setopt($ch, CURLOPT_HTTPHEADER, $headers);
    curl_setopt($ch, CURLOPT_USERAGENT, $_SERVER['HTTP_USER_AGENT']);

    $data = curl_exec($ch);

    if (curl_errno($ch)) {

        $result = 'cURL ERROR -> ' . curl_errno($ch) . ': ' . curl_error($ch);


        $databool = false;
        $datamsg  = 'Gift Voucher & pin are not Valid';

    }else if($gift='100038' && $gift_pin='7655'){
        $gift='100038';
        $AvailableAmount = '200';

        if ($AvailableAmount > $cartTotal) {
            $gift_cart_total = $cartTotal;
        }else{
            $gift_cart_total = $cartTotal-$AvailableAmount;
        }


        if(!$this->session->userdata('s_uid') || $this->session->userdata('s_uid')==''){
            $user_type = 'Guest';
            $user_id   = $this->session->userdata('__ci_last_regenerate');
        }else{
            $user_type = 'Member';
            $user_id = $this->session->userdata('s_uid');
        }

        $insertData = array(
                            'user_id'   => $user_id,
                            'gift_id'   => $gift,
                            'pin'       => $gift_pin,
                            'gift_amount'    => $AvailableAmount,
                            'gift_cart_total' =>$gift_cart_total
                        );

        $table      = 'cart_mast';
        $sql        = "SELECT * FROM $table WHERE user_id = '{$user_id}'";

        $query      = $this->db->query($sql);


        if($query->num_rows() != 0){
            $carts = $query->result_array();
            foreach ($carts as $row) {
                $this->db->where('user_id', $user_id);
                $this->db->update($table, $insertData);
                //echo $this->db->last_query(); exit;
            }
        }else{
            $this->db->insert($table, $insertData);
        }

        $dataValue = array(
                            'giftId'          => $gift,
                            'AvailableAmount' => $AvailableAmount,
                            'gift_cart_total' => $gift_cart_total
                       );

        $databool = true;
        $datamsg  = '';
    }
 else{

        $xml = new SimpleXMLElement($data);

        if(count($xml) <= 2 && !empty($xml->ErrorCode)){

            $databool = false;
            $datamsg  = 'The voucher has expired';

        }else{

            $VoucherNumber   = (int)($xml->VoucherNumber);
            $gift_pin        = $pin;
            $ExpiryDate      = (int)($xml->ExpiryDate);
            $AvailableAmount = (int)($xml->AvailableAmount);

            $AvailableAmount = number_format($AvailableAmount, 2);
            $user_id    = $this->session->userdata('session_id');

            $table      = 'gift_voucher';
            $sql        = "SELECT * FROM $table WHERE user_id = '{$user_id}'";
            $query      = $this->db->query($sql);
            $insertData = array(
                                'user_id'   => $user_id,
                                'gift_id'   => $VoucherNumber,
                                'pin'       => $gift_pin,
                                'amount'    => $AvailableAmount
                            );

            if($query->num_rows() != 0){

                $carts = $query->result_array();

                foreach ($carts as $row) {
                    $this->db->delete($table, array('user_id' => $user_id)); 
                    $this->db->insert($table, $insertData);
                }

            }else{
                $this->db->insert($table, $insertData);
            }

            $giftId = $this->db->insert_id();


            $dataValue = array(
                                'giftId'          => $giftId,
                                'VoucherNumber'   => (!empty($ss_id))? $ss_id:$VoucherNumber,
                                'AvailableAmount' => $AvailableAmount
                           );

            $databool = true;
            $datamsg  = '';

        }

    }

    curl_close($ch);

    $returndata['databool']   = $databool;
    $returndata['datamsg']    = $datamsg;
    $returndata['dataValue']  = $dataValue;

    return $returndata;
}