Knockout is meant to enable the whole MVVM pattern, and supports it with:
* Declarative binding syntax (a very simple way to link model properties/functions to DOM elements without writing manual "render" functions or event handlers)
* Automatic dependency tracking (so you can have arbitrary nested chains of computed properties that combine multiple observables, and so KO can work out on its own exactly which part of your UI to refresh after any given model change).
The templating stuff is a bit more baked in with KO too. Backbone, on the other hand, does more of the JSON data access stuff natively, whereas KO assumes you'll use normal jQuery Ajax for that.
(Disclaimer: I don't know backbone.js well, and I created Knockout, so you may want to make your own comparison.)
* Declarative binding syntax (a very simple way to link model properties/functions to DOM elements without writing manual "render" functions or event handlers) * Automatic dependency tracking (so you can have arbitrary nested chains of computed properties that combine multiple observables, and so KO can work out on its own exactly which part of your UI to refresh after any given model change).
The templating stuff is a bit more baked in with KO too. Backbone, on the other hand, does more of the JSON data access stuff natively, whereas KO assumes you'll use normal jQuery Ajax for that.
(Disclaimer: I don't know backbone.js well, and I created Knockout, so you may want to make your own comparison.)