xhr.onload = function()

in www/browser/FileTransfer.js [167:181]


                        xhr.onload = function () {
                            // 2xx codes are valid
                            if (this.status >= 200 && this.status < 300) {
                                const result = new FileUploadResult();
                                result.bytesSent = blob.size;
                                result.responseCode = this.status;
                                result.response = this.response;
                                delete transfers[that._id];
                                successCallback(result);
                            } else if (this.status === 404) {
                                fail(FileTransferError.INVALID_URL_ERR, this.status, this.response);
                            } else {
                                fail(FileTransferError.CONNECTION_ERR, this.status, this.response);
                            }
                        };