You can probably add some localStorage support in your app, saving a list of all created notes and some basic edit functionality. Perhaps, you can add Gist support as well (just throwing ideas around).
This may be fine for this case because it's just text but local storage limits are really low compared to the 350+MB you get with FileSaver.
> 5 MB per origin in Google Chrome, Mozilla Firefox, and Opera; 10 MB per storage area in Internet Explorer; 25MB per origin on BlackBerry 10 devices [1]
> 5 MB per origin in Google Chrome, Mozilla Firefox, and Opera; 10 MB per storage area in Internet Explorer; 25MB per origin on BlackBerry 10 devices [1]
[1] - http://en.wikipedia.org/wiki/Web_Storage