Django admin drop down menu dependent won't load

First, I know there are other post on topic but until now none worked for me hence here I am kindly asking your help.

The task is simple: in Django Admin I have a form with a drop-down menu whose select must filter and fill-in another drop-down menu.

First I tried to simply add a jQuery to my form to get the changes on field select. The .js is correctly loaded together with other Javascripts but simply nothing happen when I made a selection on the parent drop-down.

Second I tried to add the widget on form declaration. Same result as above.

Following is my last attempt, result as above:

Models.py

class Utenti(models.Model):
    nome = models.CharField(max_length = 188) 
    cognome = models.CharField(max_length = 188)
    dataNascita = models.DateField(max_length = 8, verbose_name = "Data di nascita")
    genere = models.CharField(max_length = 19, choices = generi, null = True, blank = True, verbose_name = "Genere")
    provincia = models.ForeignKey(Provincia, on_delete = models.SET_NULL, null = True)
    citta = models.ForeignKey(Comune, on_delete = models.SET_NULL, null = True, verbose_name = "Citta'")
    cf = models.CharField(max_length = 16, validators = [ validate_codice_fiscale ])
    

    class Meta:
        verbose_name = "Utente"
        verbose_name_plural = "Utenti"

    def __str__(self):
        return str(self.nome) + " " + str(self.cognome)

Admin.py

class FormUtenti(forms.ModelForm):
    class Meta:
        model = Utenti
        fields = '__all__'

    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)

        province = [('','---------')] + [(i.codice_provincia, i.name) for i in Provincia.objects.all()]

        self.fields['citta'].queryset = Comune.objects.none()

        self.fields['provincia'].widget = forms.Select(
            attrs = {
                'onchange': 'filterCities(this.value);',
            },
            choices = province
        )

class UtentiAdmin(admin.ModelAdmin):
    form = FormUtenti

    class Media:
        js = (  
                'admin/js/jquery.init.js', // to verify script not launched before jQuery init
                'admin/js/getCities.js',   
             )

getCities.js

'use strict';
{
 const $ = django.jQuery;

 function filterCities(provincia_id){
    $.ajax({
            url:"/get_cities/",
            type:"POST",
            data:{provincia: provincia_id,},
            success: function(result) {
                this.alert(result);
                cls = document.getElementById("id_citta_select");
                cls.options.length = 0;
                for(var item in result) {
                    cls.options.add(new Option(item, result[item]));
                }
             },
             error: function(e) {
                 alert(JSON.stringify(e));
             },
    });
 }
}

views.py

def get_cities(request):
    test_request_log = TestRequestLog(test_request_message= request)
    test_request_log.save()
    provincia_id = request.POST.get('provincia')
    citta = Comune.objects.filter(provincia_id = provincia_id).order_by('name')
    return JsonResponse({
        "data": [{'citta': c.name} for c in citta],
    })

urls.py

    path('get_cities/', views.get_cities, name='get_cities'),

I'm pretty sure the code don't go beyond the Javascript, otherwise I should see the ajax call somewehere and definetely the request in the test log (request btw I manually tested with success).

Any fresh idea?

Thank you

It was a reference error with the function name. Solved thanks to this other post and the console log.