I read about the concept of static JavaScript apps in this Dropbox technote written by Victor Costan in August 2012. Here's the opening paragraph.
Thanks to recent improvements in browser support and VM performance, I often find myself writing small and medium applications completely in JavaScript, whenever I can get away with it. JavaScript runs on users' browsers, so all the application's files are static, and can be served by any plain old file server such as nginx, pretty much any Web hosting service, and your humble Dropbox.
It's an amazing document, because it predicts apps like Fargo . And it also explains why we were able to go so far with Dropbox. They planned for it.
I wish that every company that makes a server with an API would read this document, and do the work that Dropbox did to be friendly to static JavaScript apps.
Basically, it should be possible to write a static JavaScript app that talks with your platform without requiring a server app acting as a proxy. That means either having CORS set for it, or using JSONP.
This is a beautiful way to deploy apps, and we should be encouraging it.