code: function _convertDataType(text, type) {
      switch (type) {
      case "json":    return JSON.parse(text);                      // -> Object
      case "document":return _createHTMLDocument(text);             // -> Document|String
      case "arraybuffer":
      case "blob":    return DataType["Array"]["fromString"](text); // -> ByteArray
      }
      return text;
  }
docs: /*
  function XHRProxy_convert() { // @ret Any
  var xhr = this._xhr;
  var status = xhr["status"];
  var readyState = xhr["readyState"];
  
  if (readyState === READY_STATE_DONE) {
  if ( _isSuccess(status, /^file\:/.test(this._lastRequestURL)) ) {
  return _convertDataType(xhr["responseText"],
  xhr["responseType"]);
  }
  }
  return "";
  }