Problems with ajax

My setup is Windows 10, Wamp version 3.0.6 and Codeigniter 3.0.6. I am trying to use the Calendar class to generate a calendar that will permit content updating by clicking on a particular date. I am following an old tutorial by Burak Guzel (https://www.youtube.com/watch?v=qMsEAtXtE2g) who uses ajax. The calendar appearance on the page seems correct. My jquery code, copying his (apart from the csrf elements), is:

Code:

    $('.calendar .day').click(function() {

        var name = '<?php echo $this->security->get_csrf_token_name(); ?>'
        var hash = '<?php echo $this->security->get_csrf_hash(); ?>'

        day_num = $(this).find('.day_num').html();
        day_data = prompt('Enter stuff', $(this).find('.content').html());
        if (day_data != null) {
            $.ajax({
                url: window.location,
                type: 'post',
                data: {
                    day: day_num,
                    data: day_data,
                    name: hash
                },
                success: function(msg) {
                    location.reload();
                }
            });
        }
    });

The prompt appears correctly when I click on a date and Firefox developer tools console shows the POST with the correct url but with a 403 Forbidden error. I'm guessing this is a csrf issue but when I try to test this by setting 'csrf_protection' to FALSE the console shows no POST taking place at all. I'm also wondering whether Codeigniter 3 which I am using differs significantly in this respect from the version he was using and so the ajax code syntax is wrong?

Can anyone suggest what might be going on?