Описание тега angularjs-controller

AngularJS promotes the MVVM Design pattern.

The angularjs controller exposes the data that is to be displayed into the html view. It plays the essential role of the ModelView in the MVVM design pattern. The view is a part of the HTML template.

When a Controller is attached to the DOM via the ng-controller directive, Angular will instantiate a new Controller object, using the specified Controller's constructor function. A new child scope will be available as an injectable parameter to the Controller's constructor function as $scope.

ngController
The ngController directive attaches a controller class to the view. This is a key aspect of how angular supports the principles behind the Model-View-Controller design pattern.

Reference:
https://docs.angularjs.org/guide/controller
https://docs.angularjs.org/api/ng/directive/ngController