CSRF giving problem with ajax

I use CSFR protection on my site which is massively Ajaxified. I use a jquery plugin (https://github.com/carhartl/jquery-cookie) that makes handling cookies simple:
<script>
var csrf_token = $.cookie('csrf_token');
</script>

Then whenever I'm POSTing data with Ajax, I just need to include the csrf_token in the data object that's sent to the CI server.

Works really well.

I do the same. massive AJAX usage on CI3, with token refreshing on every request.

So i added this to my footer:

Code:

    $(document).ready(function () {
        $('form').submit(function () {
        var csrf_cookie_val = $.cookie(csrf_cookie_name_goes_here);
        $(this).find('input[type="hidden"]')
            .filter('[name="' + csrf_var_name_goes_here + '"]')
            .val(csrf_cookie_val);
        });
    });