AngularJS is a structural framework for dynamic web apps. It lets you use HTML as your template language and lets you extend HTML's syntax to express your application's components clearly and succinctly. Angular's data binding and dependency injection eliminate much of the code you would otherwise have to write.
Controllers in Angular are simple functions that have one job only, which is to manipulate the scope. For example, you can use it to prefill data into the scope from the server or implement business logic validations. Unlike other frameworks, controllers are not objects and don’t inherit from anything.
If controllers are so simple, then where should all the heavy lifting be performed? Angular introduces Services to do just that.
Services are exactly what they sound like. They don’t get involved with the MVC of your app, but simply provide an outward API to expose whatever you want it to expose. Most of the time it syncs up to a server to maintain an offline data store and exposes methods to push and pull data to and from a server. Or it can be used to create a resource sharing service that allows multiple controllers to share the same resources.
Services are designed to be standalone objects separate from your app and allow your controller to be remain lean and dedicated to the view and scope that it is assigned to. Of course, implementing services is not required and it is perfectly acceptable to do some light lifting inside your controller to avoid over complexity.Swappy_Gaj, if this helps please login to Mark As Answer. | Alert Moderator