Question: I understand that `$Broadcast()`, `$Emit()` And `$On()` are used to raise an event in one controller and handling in another controller. If possible, can someone just give me some real time example on the usage of above three as I am new to `angular JS`?

I have gone through the following links and understand the basic usage.

<http://www.binaryintellect.net/articles/5d8be0b6-e294-457e-82b0-ba7cc10cae0e.aspx>

Answer: 
**$emit**

It dispatches an event name upwards through the scope hierarchy and notify to the registered `$rootScope.Scope` listeners. The event life cycle starts at the scope on which `$emit` was called. The event traverses upwards toward the root scope and calls all registered listeners along the way. The event will stop propagating if one of the listeners cancels it.

**$broadcast**

It dispatches an event name downwards to all child scopes (and their children) and notify to the registered `$rootScope.Scope` listeners. The event life cycle starts at the scope on which `$broadcast` was called. All listeners for the event on this scope get notified. Afterwards, the event traverses downwards toward the child scopes and calls all registered listeners along the way. The event cannot be canceled.

**$on**

It listen on events of a given type. It can catch the event dispatched by `$broadcast` and `$emit`.

---

**Visual demo:**

Demo working code, visually showing scope tree (parent/child relationship):  

<http://plnkr.co/edit/am6IDw?p=preview>

Demonstrates the method calls:

```
  $scope.$on('eventEmitedName', function(event, data) ...
  $scope.broadcastEvent
  $scope.emitEvent

```
This little example shows how the `$rootScope` emit a event that will be listen by a children scope in another controller.

```
(function(){

angular
  .module('ExampleApp',[]);

angular
  .module('ExampleApp')
  .controller('ExampleController1', Controller1);

Controller1.$inject = ['$rootScope'];

function Controller1($rootScope) {
  var vm = this, 
      message = 'Hi my children scope boy';

  vm.sayHi = sayHi;

  function sayHi(){
    $rootScope.$broadcast('greeting', message);
  }

}

angular
  .module('ExampleApp')
  .controller('ExampleController2', Controller2);

Controller2.$inject = ['$scope'];

function Controller2($scope) {
  var vm = this;

  $scope.$on('greeting', listenGreeting)

  function listenGreeting($event, message){
    alert(['Message received',message].join(' : '));
  }

}

})();

```

<http://codepen.io/gpincheiraa/pen/xOZwqa>

The answer of @gayathri bottom explain technically the differences of all those methods in the scope angular concept and their implementations `$scope` and `$rootScope`.