Backbone is a simple but robust client-side JavaScript library for building applications. Data is represented as Models, which can be gathered into Collections. Model state is displayed with Views.

Backbone attempts to provide the minimal set of data structure and user interface primitives that would be useful in a JavaScript web application. Its goal is to provide these tools without dictating how to use them or what your use-case should look like. This means that the developer is given a lot of freedom to design the full experience of their application.

Collections are ordered sets of models. You can bind "change" events to be notified when any model in the collection has been modified, listen for "add" and "remove" events, fetch the collection from the server, and use a full suite of Underscore.js methods.

Any event that is triggered on a model in a collection will also be triggered on the collection directly, for convenience. This allows you to listen for changes to specific attributes in any model in a collection.