Just as example from github, it works. https://github.com/eligrey/FileSaver.js
<script src="https://stackoverflow.com/questions/21997057/FileSaver.js"></script>
<script type="text/javascript">
var blob = new Blob(["Hello, world!"], {type: "text/plain;charset=utf-8"});
saveAs(blob, "hello world.txt");
</script>