Knockout.js (http://knockoutjs.com/) is an opensource javascript library that simplifies UI and javascript. If you are using c#, you end up duplicating the view model, both in Javascript and in c#. This library will convert your c# viewmodel, straight into knockout viewmodel.

namespace knockoutExample { public class Restaurant : Knockout.ViewModel { public int RestaurantId { get; set; } public string Name { get; set; }

}

}

public string KnockOutJs() { restViewModel = new Restaurant(); koCreator = new Knockout.KoCreator()

//Set your controller name
koCreator.PageName = "Home";

//Add your viewmodel Restaurant is the name of the model we want in javascript
koCreator.AddViewModel("Restaurant", restViewModel.GetType());

//Add a javascript function subscription.  This will call the javascript function test() everytime the name is changed
koCreator.AddJsSubscription("Name","test");

//This will return the javascript, we pass in the controller so that Knockout Creator can bind subscriptions
return koCreator.GenerateJs(this);

}

//Add a custom attribute specifying the variable that when changed will trigger this via AJAX [KoMethod("RestaurantId")]

//The method accepts one attribute, our viewmodel. This will be passed back using AJAX public JsonResult GetRestaurantById(knockoutExample.Restaurant viewModel) {

//get the restaurantId that has been posted
int restaurantId = viewModel.RestaurantId;

//Load the record from the db
Restaurant restaurant = _restaurantRepository.Load(restaurantId);

// set the viewmodel name
    viewModel.Name = restaurant.Name

//return the viewmodel back to the browser
return Json(viewModel);

}

Everytime the RestaurantId is updated a call will be made to the server and will run GetRestaurantById.