Set currency based on IP address

PHP Code:

// set default currency code if not set already in index()
if (!$this->session->userdata('currency_code')) {
    $this->session->set_userdata('currency_code', 'USD');
    $this->data['ajax_currency'] = true;
}

...

public function set_currency_ajax() {
            
        $country_info = file_get_contents('https://freegeoip.net/json/' . $this->input->ip_address());
        $country_info = json_decode($country_info, true);

        $countries_in_euro = array('AT', 'BE', 'CY', 'DE', 'EE', 'FI', 'FR', 'GR', 'IE', 'IT', 'LT', 'LV', 'LU', 'MT', 'NL', 'PT', 'SK', 'SI', 'ES');

        if (in_array($country_info['country_code'], $countries_in_euro)) {
            $this->session->set_userdata('currency_code', 'EUR');
        }
        else if ($country_info['country_code'] == 'GB') {
            $this->session->set_userdata('currency_code', 'GBP');
        }
        else {
            $this->session->set_userdata('currency_code', 'USD');
        }

        $response = array(
            'sess_currency' => strtolower($this->session->currency_code),
        );

        // echo json_encode($response);
        $this->output->enable_profiler(false)->set_output(json_encode($response))->_display();
        exit();
    }

PHP Code:

<span data-eur="€100" data-gbp="£75" data-usd="$115" class="price-span">$115</span>

...


<?php if(isset($ajax_currency) && $ajax_currency === true): ?>
        <script type="text/javascript">
            $(document).ready(function() {
                $.post("<?php echo site_url('set_currency_ajax'); ?>", {}, function(response) {
                    alert(response.sess_currency);
                    $('.price-span').text( $(this).attr('data-' + response.sess_currency) );
                });
            });
        </script>
    <?php endif; ?>