How to load a script with Ajax in Django?

Question

Django

Question 1
In the base template, Django made 2 functions for Ajax requests

function ajax_get(url, block_id) {
             $.ajax({
                 url: url,
                 type: 'GET',
                 dataType: 'html',
                 success: function (data) {
                     $(block_id).html(data);
                 }
             })
         }

        function ajax_post(url, form_id, block_id) {
            var form = $(form_id).serialize();
                $.ajax({
                    url: url,
                    type: 'POST',
                    data: form,
                    dataType: 'html',
                    success: function (data) {
                        $(block_id).html(data);
                    }
                });
                return false;
        }

And in the future, I just use these functions to load templates instead of writing my own function for each request. If I put these functions in a separate ajax.js file and connect it, then for some reason they do not work. Why?
And Question 2
One of the templates has a script that loads another script

$( document ).ready(function() {
        loadScript("{% static 'js/plugin/bootstraptree/bootstrap-tree.min.js' %}");
    });
</script>

It works on the first boot, but then it doesn't.
How to fix it?