I am writing simple console apps in C#. But I would like it if I had a good UI to use. Since we live in an age where everything is run off the internet or intranet through a web browser, should I use a javascript frame work? What is a good choice for that? If I am using the UI to access and upload local files, like excel data files, what would be a good suggestion to use? Is there a bare-bones javascript suggestion that I can use?

I have a js script hosted on a URL. My script places a widget View on a site where it is placed. Now for presentation purpose, site owners wants to see the demo with their site structure placed with my widget.