No data from streaming api

[0xB49]

Hello.

I try to use streaming api for my browser extension (currently do test on Chrome).
Because it is browser extension, I need to implement purely in Javascript.

access token & access token secret are correctly obtained (I find exactly same value listed in OAuth Signature Generator).

And, when I try to access https://userstream.twitter.com/1.1/user.json with GET, I can’t receive any response (my XMLHttpRequest doesn’t work. status == 0 and, readyState == 1, even I call xhr.send() ).
On the other hand, when I try to access https://stream.twitter.com/1.1/statuses/sample.json with GET (all settings except for endpoint URL are unchange), I correctly receive tweets from Twitter.

Note: I connect to https://userstream.twitter.com/1.1/user.json with cURL, it works.

I share you my code snippet below:

var CryptoJS = require("../../node_modules/crypto-js");

var apiKey = "XXXXXXXXXXXXXXXXXXXXXXXXXX";
var apiSecret = "YYYYYYYYYYYYYYYYYYYYYYYYY";
var accessTokenKey = "ZZZZZZZZZZZZZZZZZZZZZZZZZZ";
var accessTokenSecret = "WWWWWWWWWWWWWWWWWWW";

function makeStream(){
    var requestURL = "https://userstream.twitter.com/1.1/user.json";
    var requestMethod = "GET";
    var signatureKey = encodeURIComponent(apiSecret)+"&"+encodeURIComponent(accessTokenSecret);

    // generate parameters
    var msec = Date.now();
    var params = {
        "oauth_consumer_key" : apiKey,
        "oauth_nonce" : msec,
        "oauth_signature_method" : "HMAC-SHA1",
        "oauth_timestamp" : Math.floor(msec / 1000),
        "oauth_token" : accessTokenKey,
        "oauth_version" : "1.0"
    };

    // encode each parameter
    var sortedKeys = []
    for(var key in params){
        params[key] = encodeURIComponent(params[key]);
        sortedKeys.push(key)
    }

    sortedKeys.sort();
    var requestParams = "";

    for(var key in sortedKeys){
        requestParams += sortedKeys[key];
        requestParams += "=";
        requestParams += params[sortedKeys[key]];
        requestParams += "&";
    }
    requestParams = String(requestParams).substring(0, requestParams.length-1)

   for(var key in sortedKeys){
        requestParams += sortedKeys[key];
        requestParams += "=";
        requestParams += params[sortedKeys[key]];
        requestParams += "&";
    }
    requestParams = String(requestParams).substring(0, requestParams.length-1)

    var encodedRequestMethod = encodeURIComponent(requestMethod);
    var encodedRequestURL = encodeURIComponent(requestURL);
    var signatureData = encodedRequestMethod+"&"+encodedRequestURL+"&"+encodeURIComponent(requestParams);

    var hash = CryptoJS.HmacSHA1(signatureData,signatureKey);
    var signature = CryptoJS.enc.Base64.stringify(hash);

    params["oauth_signature"] = encodeURIComponent(signature);
    var headerParams = ""
    for(var key in params){
        headerParams += key
        headerParams += "="
        headerParams += '"'
        headerParams += params[key]
        headerParams += '"'
        headerParams += ", "
    }
    headerParams = String(headerParams).substring(0, headerParams.length-2);

    xhr = new XMLHttpRequest();
    xhr.open(requestMethod, requestURL, true);
    xhr.setRequestHeader("Authorization", "OAuth "+headerParams);
    xhr.onreadystatechange = function () {
        // this is just for debug. And, this callback function doesn't fire.
        console.log(xhr.status);
        console.log(xhr.readyState);
        console.log(xhr.responseText);
    }
    xhr.send(null);
    console.log("status: " + xhr.status); // status == 0
    console.log("readystate: " + xhr.readyState); // readyState == 1. even I call send() function