How to correctly display data stored in an external model without refreshing the page?

Question

I am trying to display a User's name on top of a box where they enter their Employee # in a form, without having to refresh the page.

For example, they enter their # and then after they click/tab onto the next field, it renders their name on top, which comes from the database, so the user knows they've entered the correct info. This name is stored in a separate model, so I try to retrieve it using the "id/number".

I am not too familiar with AJAX but after reading a few similar questions it seems like an AJAX request would be the most appropriate way to achieve this. I tried to make a function get_employee_name that returns the name of the person based on the way I saw another ajax request worked, but I'm not sure how to implement this so it displays after the # is entered.

My page currently loads, but when I check the network using F12, there is never a call to the function/url that searches for the name to display it on the page. I'm not sure where I might be missing the part that connects these two areas of the code, but I have a feeling it has to do with the html tag where the call is supposed to happen, as I am not too familiar with html and Django.

models.py

class EmployeeWorkAreaLog(TimeStampedModel, SoftDeleteModel, models.Model):
    employee_number = models.ForeignKey(Salesman, on_delete=models.SET_NULL, help_text="Employee #", null=True, blank=False)
    work_area = models.ForeignKey(WorkArea, on_delete=models.SET_NULL, null=True, blank=False)
    station_number = models.ForeignKey(StationNumber, on_delete=models.SET_NULL, null=True,  blank=True)

This is the model where the name is stored

alldata/models.py

class Salesman(models.Model):
    slsmn_name = models.CharField(max_length=25)
    id = models.IntegerField(db_column='number', primary_key=True)

I was reading I can add to the "attrs" in the widget an 'onchange' part, but I am not too familiar with how to approach this and tying it to the ajax request from forms and not the html.

forms.py

class WarehouseForm(AppsModelForm):
    class Meta:
        model = EmployeeWorkAreaLog
        widgets = {
            'employee_number': ForeignKeyRawIdWidget(EmployeeWorkAreaLog._meta.get_field('employee_number').remote_field, site, attrs={'id':'employee_number_field'}),
        }
        fields = ('employee_number', 'work_area', 'station_number')

views.py

class EnterExitArea(CreateView):
    model = EmployeeWorkAreaLog
    template_name = "operations/enter_exit_area.html"
    form_class = WarehouseForm

    def form_valid(self, form):
        # do submission stuff..


def get_employee_name(request):
    employee_number = request.GET.get('employee_number')

    try:
        employee = Salesman.objects.get(id=employee_number)
    except Salesman.DoesNotExist:
        return JsonResponse({'error': 'Employee not found'}, status=404)

    employee_name = employee.slsmn_name
    return JsonResponse({'employee_name': employee_name})

urls.py

urlpatterns = [
    url(r'enter-exit-area/$', EnterExitArea.as_view(), name='enter_exit_area'),

    path('ajax/load-stations/', views.load_stations, name='ajax_load_stations'),
    path('get-employee-name/', views.get_employee_name, name='ajax_get_employee_name'),
]

The ajax request I tried to create is at the end of this html. I modified a similar request I found, but it does not actually display anything on the screen, not sure if I'm missing an area where the request is actually never being called, as I am not too familiar with how these types of requests work.

enter_exit_area.html

{% extends "base.html" %}

{% block main %}
    <form id="warehouseForm" action="" method="POST" data-stations-url="{% url 'operations:ajax_load_stations' %}" novalidate >
        {% csrf_token %}
        <div>
            <h1 get-employee-name-url="{% url 'operations:ajax_get_employee_name' %}"></h1>
            <div>
                {{ form.employee_number.help_text }}
                {{ form.employee_number }}
            </div>
            <div>
                {{ form.work_area.help_text }}
                {{ form.work_area }}
            </div>
        </div>

        <div>
            <div>
                <button type="submit" name="enter_area" value="Enter">Enter Area</button>
            </div>
        </div>
    </form>

<!-- This is the dependent dropdown script -->

    <script src="https://code.jquery.com/jquery-3.3.1.min.js"></script>
    <script>
        $("#id_work_area").change(function () {
            var url = $("#warehouseForm").attr("data-stations-url");
            var workAreaId = $(this).val();

            $.ajax({
                url: url,
                data: {
                    'work_area': workAreaId
                },
                success: function (data) {
                    $("#my-hidden-div").show(); // show it
                    $("#id_station_number").html(data);
                    // Check the length of the options child elements of the select
                    if ($("#id_station_number option").length == 1) {
                        $("#id_station_number").parent().hide(); // Hide parent of the select node
                    } else {
                        // If any option, ensure the select is shown
                        $("#id_station_number").parent().show();
                    }
                }
            });
        });
     </script>

<!-- -->

    <script>
        $("#id_employee_number").change(function () {
            var employee_number = $(this).val();
            var url = $("#warehouseForm").attr("get-employee-name-url");

            $.ajax({
            url: url,
            type:'GET',
            data: {
                'id': employee_number
            },
            success: function (data) {
                var employee_name = data['employee_name'];
                $('#employee_name')[0].innerHTML = employee_name;
            },
            error : function (data) {
                var error_message = data['error'];
                $('#employee_name')[0].innerHTML = error_message;
            }
            });
        });
    </script>

{% endblock main %}

What could be causing nothing to render on the page? Is there a call missing in the html portion?

I assume there needs to be a place where the onchange() goes, but I'm not sure where this would be in since the form fields are it's own thing, without tags.

Answer 1

With regards to

var url = $("#warehouseForm").attr("get-employee-name-url");

The id is referring to the form which does not have an attribute name "get-employee-name-url". Your url is actually in here

<h1 get-employee-name-url="{% url 'operations:ajax_get_employee_name' %}"></h1>

So maybe add an id to it like this

<h1 id="url" get-employee-name-url="{% url 'operations:ajax_get_employee_name' %}"></h1>

and then you can access it like you were

var url = $("#url").attr("get-employee-name-url");