Any remotely modern web site is running JavaScript on some level.

As browsers and personal pcs have continued to improve, so, too, has the ability to create robust web applications.

A very popular use for JavaScript is to create presentations as websites.

While the browser hasn’t been a traditional games platform in the past, recently it has become a robust venue for games.

 Pebble has created Pebble.js, a small javascript framework that allows a developer to create an application for the Pebble line of watches in JavaScript.

One of the most powerful things you can do with JavaScript is build applications for non-web contexts.