[Moo] Problem with Request.JSON

[Maxim Lacrima]

Hi!

I think I have very trivial problem Request.JSON, but I can't resolve it:

var tariffVo = new Request.JSON({
    url: '/tariff',
    method: 'post',
    onSuccess: function() {
        alert('tariff received');
    },
    onRequest: function() {
        alert('request is being sent');
    }
});
tariffVo.send();

For some reason onSuccess callback is never called, though I can see
that request was successful in firebug console:
POST http://localhost:8080/tariff 200 OK 37ms

onRequest callback is always called.

So what is wrong with my code?

Thanks in advance.

-- 
with regards,
Maxim