Google Adwords and CodeIgniter GET Variable Callback URL
If you are using CodeIgniter 2, you can do:
$config['allow_get_array'] = TRUE;$config['enable_query_strings'] = FALSE;
You need to do the following 1- $config['enable_query_strings'] = TRUE;
2- $config['permitted_uri_chars'] = 'a-z 0-9~%.:_-\?=&';
AND remove the "?" from your htaccess file.
3- RewriteRule ^(.*)$ index.php/$1 [QSA,L]