ajax

ajax = (function(){
    var  _ = {};

    /* options = {success: function(request) {...}, fail: function(code, text) {...} } */
    _.plain = function(method, url, options, params) {
        options = options || {};
        var req = new XMLHttpRequest;

        if (options.success || options.fail) {
            req.onreadystatechange = function() {
                if (req.readyState  == 4) {
                    if (req.status >= 200 && req.status < 300) {
                        if (options.success) {
                            options.success(req);
                        }

                        return;
                  }

                  if (options.fail) {
                      options.fail(req.status, req.statusText);
                  }
              }
          }
      }

      req.open(method, url);

      if (method.toUpperCase() == 'POST') {
          req.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded');
          params = buildQueryString(params);
      }

        if (options.before) {
            options.before(req);
        }

        req.send(params || null);
    }

    _.get = function(url, options) {
        _.plain('GET', url, options, null);
    }

    _.post = function(url, params, options) {
        _.plain('POST', url, options, params);
    }

    return _;
})();