def count_comments(request):
    if request.method == 'POST':
        return HttpResponse(Comment.objects.count())

class SomeForm(forms.ModelForm):
    class Meta:
        widgets = {
               'income_date' : forms.TextInput(attrs={'class':'calendar'}),
               'income_order_date' : forms.TextInput(attrs={'class':'calendar'}),
               'outgoing_date' : forms.TextInput(attrs={'class':'calendar'}),
               'outgoing_order_date' : forms.TextInput(attrs={'class':'calendar'}),
         }

pip install django-widget-tweaks

{% load widget_tweaks %}
{% render_field form.income_date class="calendar" %}

class JsonFormResponseMixIn(object):
    def _to_json(self, j):
        callback = self.request.GET.get('callback')
        if callback:
            j[JSONP_KEY] = callback
        return j
    def get_json_object(self):
        if hasattr(self.object, '__json__'):
            return self.object.__json__()
        else:
            return self.get_default_json_object()
    def get_default_json_object(self):
        return dict(
            id=self.object.id,
            name=unicode(self.object)
        )
    @to_json
    def form_valid_response(self):
        return self._to_json(dict(
            success = True,
            object = self.get_json_object(),
        ))
    def form_valid(self, form):
        self.object = form.save()
        return self.form_valid_response()
    @to_json
    def form_invalid(self, form):
        return self._to_json(dict(
            success = False,
            errors = [ (unicode(field.label), u", ".join(field.errors)) for field in form if field.errors],
        ))

    function showFormEror(data) {
                error_box.empty().show();
                $.each(data.errors, function(index, error) {
                    error_box.append('<p><b>' + error[0] + '</b>: ' + error[1] + '</p>');
                });
                if (data.message)
                    error_box.append('<h2>' + data.message + '</h2>');
            };