<form action="{% url 'some_url' %}" class="some-class" method="post"">
...
    <button class="button_class"  type="submit"">Submit</button>
</form>


$('.button_class').on('click', function(e) {
            e.preventDefault();
            $.ajax({
                type: 'POST',
                url: '{% url 'some_url' %}',
                cache: false,
                data: {
                    form: $('form[class=some-class]').serialize()
                },
                success: function(data){
                    console.log('Success ajax')
                },
                error: function(data){
                    console.log('Fail ajax')
                }
            });
            return false;
    });

#views.py

def post(self, request, *args, **kwargs):
    ...
    if form.is_valid():
        return self.form_valid(form)
    else:
        data = {
                'result': 'error',
                'message': 'Form invalid',
                'errors': form.errors.as_json()
            }
        return JsonResponse(data)