class LoginForm(forms.Form):
    username = forms.CharField(max_length=100)
    password = forms.CharField(widget=forms.PasswordInput(render_value=False),max_length=100)

def login_view(request):
	if request.method == 'POST':
		username = request.POST['email']
		password = request.POST['password']
		user = authenticate(username=username, password=password)
		if user is not None and user.is_active:
			login(request, user)
			return HttpResponseRedirect("/n1.html")# Redirect to a success page.
		return HttpResponseRedirect("/invalid/")# Return a 'disabled account' error message
	form=LoginForm()
	return render(request, 'enter.html', {'login_form': LoginForm})

(r'^login/$', login_view),

class LoginForm(forms.Form):
    username = forms.CharField(label=_('Username'), max_length=30)
    password = forms.CharField(label=_('Password'), max_length=30)
    class Meta:
        widgets = dict(password=forms.PasswordInput)
    def clean_username(self):
        username = self.cleaned_data["username"]
        if not username:
            raise forms.ValidationError(_("THIS FIELD IS REQUIRED"))
        try:
            user = get_user_model().objects.get(username=username)
            if not user.is_active:
                raise UserIsDisabled
            return username
        except get_user_model().DoesNotExist:
            raise forms.ValidationError(_("THE USER IS NOT EXIST"))
        except UserIsDisabled:
            raise forms.ValidationError(_("THE USER IS DISABLED"))
    def clean_password(self):
        username = self.cleaned_data["username"]
        password = self.cleaned_data["password"]
        user = authenticate(username=username, password=password)
        if not user:
            raise forms.ValidationError(_("THIS PASSWORD IS INCORRECT"))
        return password
class LoginView(FormView):
    form_class = LoginForm
    def form_valid(self, form):
        username = form.cleaned_data.get('username')
        password = form.cleaned_data.get('password')
        user = authenticate(username=username, password=password)
        login(self.request, user)
        payload = {'success': True}
        return HttpResponse(json.dumps(payload, cls=LazyEncoder), content_type='application/json')
    def form_invalid(self, form, *args, **kwargs):
        # Ошибки формы кидаем в словарь, чтобы отправить клиенту, функция ниже
        payload = {'success': False, 'errors': as_json(form.errors)}
        return HttpResponse(json.dumps(payload, cls=LazyEncoder), content_type='application/json')
def as_json(errors):
    return dict((k, map(unicode, v)) for k, v in errors.items())

// Просто функция которая пишет в Placeholder ошибки поля , а общие ошибки формы в добавленный перед формой DIV
function AjaxFormError(errors, $form) {     
    for (var k in errors) {
        // Не забываем стереть введенные значения в форме, перед тем как записать ошибки
	$('[name="'+k+'"]').val('').prop('placeholder', errors[k]);
       if (k == '__all__')   // Если ошибки не поля, а всей формы- допишем слой выше
	    { $form.prepend('<div class="error">' + errors[k] + '</div>'); }
    }
}
// Ииии..все вместе :)
$(document).ready(function(){
    $('#login_link').click( function() {
        $.post("{% url 'login' %}", $("#login_form").serialize(),function(data) {
	    $("#login_form").find('.error').html('');
	    if (data.success == true) { window.location.reload(); }  else { AjaxFormError(data['errors'], $('#login_form')); }
	    });
	return false;
        });
})

def login_view(request):
	if request.method == 'POST':
		username = request.POST['email']
		password = request.POST['password']
		user = authenticate(username=username, password=password)
		if user is not None and user.is_active:
			login(request, user)
			return HttpResponseRedirect("/n1.html")
		return render_to_response('enter.html', {'error': True})
	form=LoginForm()
	return render(request, 'enter.html', {'login_form': LoginForm})

enter.html
 {% if error %}
'Неверное имя или пароль'
 {% endif %}
    <form class="form-signin" action="" method="post">
    	{% csrf_token %}
    	<h2 class="form-signin-heading">Пожалуйста, авторизуйтесь</h2> 
        <input class="input-block-level" type="text" name="email" value="" id="email" placeholder="Email адрес">
        
        <input class="input-block-level" type="password" name="password" value="" id="username" placeholder="Пароль">
        <button class="btn btn-large btn-primary" type="submit">Вход</button>
        <input type="hidden" name="next" value="{{next|escape}}" >
        
    </form>