dinamis baseURL

ganti base url site/config/config.php

beri tanda double slash //
//$config['base_url'] = 'http://localhost/site/';

$http = 'http' . ((isset($_SERVER['HTTPS']) && $_SERVER['HTTPS'] == 'on') ? 's' : '') . '://';
$newurl = str_replace("index.php","", $_SERVER['SCRIPT_NAME']);
$config['base_url']    = "$http" . $_SERVER['SERVER_NAME'] . "" . $newurl;