Problem: Receiving empty answer using AJAX and Oauth (Twitter)

Problem: Receiving empty answer using AJAX and Oauth (Twitter)

Hi, I'm using jQuery's AJAX to interact with Twitter.
I'm trying to implement, at first, the authentication through oauth. So, I'm using Oauth JavaScript library (from Google Code) to build data to be sent, and then using jQuery's AJAX to send it.

In the very first step, I send the requesition for token:

var urltw = "http://twitter.com/oauth/request_token";
var datasend = null;
var accessor = {
consumerKey: "my_key_here",
consumerSecret: "my_secret_here"
}; 

var message = {
action: urltw,
method: "GET",
parameters: {
oauth_nonce: null,
oauth_signature_method: "HMAC-SHA1",
oauth_signature: null,
oauth_timestamp: null,
oauth_version: null
}
};

OAuth.completeRequest(message, accessor);        
OAuth.SignatureMethod.sign(message, accessor);
datasend = OAuth.formEncode(message.parameters);

// send request to 'url'
$("#request").append(datasend.split("&").join("<br>"));

$.ajax({
  url: urltw,
  data: datasend,
  dataType: "json",
  async: false,
  success: function(reslt, stat, obj){
  $("#result").append(reslt);
  }
});

So, I look through wireshark: the answer is correct, Twitter responds with 200 OK and the data inside the body of the response.
However, when I try read it in the param "reslt" in success, it is always empty. Looked into obj with firebug (using Firefox here), and the answer really is not there in any property.
I'm using this script locally (not through a server, neither localhost, I'm just opening the html file). 

So, anybody knows how to read the response successfully?