BLOB Save

functions.download = function (param, successCallback, errorCallback, targetFile, totalSize) {
    for (i in param) {
        var url = param[i].path + param[i].fileName + param[i].fileType;
        var filename = param[i].fileName + param[i].fileType;
        var authToken = cloud.backend.authToken;

        var xhr = new XMLHttpRequest();
        xhr.onreadystatechange = function () {
            if (xhr.readyState == 4) { // complete.
                if (xhr.status >= 200 && xhr.status < 300) {
                    var blob = this.response;
                    successCallback(blob, filename, functions.performSaveSuccess, functions.performSaveError);
                } else {
                    // response not successfull
                    var error = /<d:error/;
                    if (error.test(xhr.responseText)) {
                        errorCallback("ResponseText: " + xhr.responseText);
                    } else {
                        errorCallback("Kein ResponeText vorhanden");
                    }
                }
            }
        };
        xhr.open("GET", url, true);
        xhr.responseType = 'blob';
        xhr.setRequestHeader("Authorization", "Basic " + authToken);
        xhr.send();
    }

functions.performSave = function (blob, filename, successCallback, errorCallback) {
    window.requestFileSystem(
                  LocalFileSystem.PERSISTENT, 0,
                  function onFileSystemSuccess(fileSystem) {
                      fileSystem.root.getFile(filename, { create: true }, function (fileEntry) {
                          fileEntry.createWriter(function (fileWriter) {
                              fileWriter.onwriteend = function (e) {
                                  successCallback();
                              };
                              fileWriter.onerror = function (e) {
                                  errorCallback(e);
                              };
                              fileWriter.write(blob);
                          }, errorCallback);
                      }, errorCallback);
                  })
}