I'm trying to make a Django form with dynamically pre-populated fields: that is, when one field (checkin_type) gets selected from a drop-down menu, other fields get automatically pre-populated with corresponding data. To this end, I would like to send a POST request to the server as soon as a drop-down option is selected.
So far I've tried the following template (following https://docs.djangoproject.com/en/2.0/ref/csrf/):
<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<script src="https://cdn.jsdelivr.net/npm/js-cookie@2/src/js.cookie.min.js"></script>
<script>
    $(document).ready(function(){
        var csrftoken = Cookies.get('csrftoken');
        $(".auto-submit").change(function() {
            $.post({
                url: "{% url 'get-checkin-type' %}",
                data: $(".auto-submit option:selected").val(),
                headers: {
                    X-CSRFToken: csrftoken
                }
            })
        });
    });
</script>
<form action="" method="post">{% csrf_token %}
    {% for field in form %}
        <div class="{% if field.name == 'checkin_type' %}auto-submit{% endif %}">
            {{ field.errors }}
            {{ field.label_tag }}
            {{ field }}
        </div>
    {% endfor %}
    <input type="submit" value="Send message" />
</form>
However, when I select a drop-down option I get a
new:17 Uncaught SyntaxError: Unexpected token -
which emanates from the X-CSRFToken: csrftoken line:
Can someone point out to me what is wrong with this code? (I tried looking it up from https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Errors/Unexpected_token but so far couldn't figure it out).
By the way, it seems from jQuery add CSRF token to all $.post() requests' data that one can also add the CSRF token to the POST request's data, but this doesn't seem like the most elegant approach to me, and the docs state that
For this reason, there is an alternative method: on each XMLHttpRequest, set a custom X-CSRFToken header to the value of the CSRF token.

 
     
    