This is TodoMVC integrated with remoteStorage.js.
You can run this by simply opening index.html in your browser, and it will even sync between multiple tabs.
From the original project source:
This application uses JavaScript with ES5 language features to implement a todo application.
JavaScript (JS) is a lightweight, interpreted, or just-in-time compiled programming language with first-class functions. While it is most well-known as the scripting language for Web pages, many non-browser environments also use it..
JavaScript - developer.mozilla.org
This implementation uses an explicit MVC pattern, with a clear file structure to reflect the architecture. The storage solution uses an in-memory data object that implements a simple array to hold the todos.