Backbone is an MVC framework for the frontend. With Backbone, you represent data as Models, which can be created, validated, destroyed, and saved to the server. Whenever a UI action causes an attribute of a model to change, the model triggers a "change" event; all the Views that display the model's state can be notified of the change so that they are able to respond accordingly, re-rendering themselves with the new information.
Backbone gives structure to web applications by providing models with key-value binding and custom events, collections with a rich API of enumerable functions views with declarative event handling, and connects it all to your existing API over a RESTful JSON interface.
You don't need to tie your models to the DOM manually, backbone takes care of that and makes making changes easier for better developer experience.