winjs download a file

gistfile1.js

console.log('download a file', device.platform, location.href);

function DownloadFile(uriString, fileName) {
    try {
        console.log("started");

        var applicationData = Windows.Storage.ApplicationData.current;
        console.log("applicationData", applicationData.localFolder.path);

        applicationData.localFolder
            .createFileAsync(fileName, Windows.Storage.CreationCollisionOption.generateUniqueName)
            .done(function (newFile) {
                console.log("test")
                var uri = Windows.Foundation.Uri(uriString);
                var downloader = new Windows.Networking.BackgroundTransfer.BackgroundDownloader();
                download = downloader.createDownload(uri, newFile);
                promise = download.startAsync()
                    .then(function () {
                        console.log("success");
                    }, error, function () {
                        console.log("progress");
                    });
            }, error);
    } catch (err) {
        error("error", err);
    }
};


function error(err) {
    console.log('err', err);
}