Tumblr API usage with OAuth: creating a text post

tumblr.api.post.text.js

var oauth = ChromeExOAuth.initBackgroundPage({
    'request_url': 'http://www.tumblr.com/oauth/request_token',
    'authorize_url': 'http://www.tumblr.com/oauth/authorize',
    'access_url': 'http://www.tumblr.com/oauth/access_token',
    'consumer_key': 'vGKikr2uBRsWoDZ947UjvSzA58HYEXDNjAer7VEXnLXlQt4Ozi',
    'consumer_secret': 'JvofKKxQ2QSiVXVaWMBZQRzC5cI86YpJzAoouIkUdlvSeYXN2e',
    'app_name': 'Photo post adder'
});

function stringify(parameters) {
    var params = [];
    for(var p in parameters) {
        params.push(encodeURIComponent(p) + '=' +
        encodeURIComponent(parameters[p]));
    }
    return params.join('&');
};

function done() {
    // Just output it.
    console.log(arguments);
};

function onAuthorized() {
    var method = 'POST';
    var url = 'http://api.tumblr.com/v2/blog/chestozo.tumblr.com/post';

    var data = {
        type: 'text',
        tags: 'text,my first post',
        title: 'First attempt',
        body: 'That\'s all folks!'
    };

    var xhr = new XMLHttpRequest();
    xhr.onreadystatechange = function(data) {
        done(xhr, data);
    };

    xhr.open(method, url, true);
    xhr.setRequestHeader('Authorization', oauth.getAuthorizationHeader(url, method, data));
    xhr.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded');
    xhr.send(stringify(data));
};

oauth.authorize(onAuthorized);