Models in Javacript Frameworks
I started creating a web service in Ruby on Rails. After some time I discovered some amazing javascript frameworks:
-Backbone
-KnockoutJs
-SproutCore
-BatmanJs
-etc..

Does that JS frameworks saves user informations in database (Model?) and are they good solution for creating web application intended to users?
Models in Javacript Frameworks
===

I started creating a web service in Ruby on Rails. After some time I discovered some amazing javascript frameworks:
-Backbone
-KnockoutJs
-SproutCore
-BatmanJs
-etc..

Does that JS frameworks saves user informations in database (Model?) and are they good solution for creating web application intended to users?