Broadcating event on button click :- 

```
$scope.onButtonClick = function(){
    $rootScope.$broadcast('onButtonClick');
}

```

And catching event in another controller :-

```
$rootScope.$on('onButtonClick',function(event){
  alert("catched");
  console.log(event);
});

```

But it caught twice even though it fired only once. Why is that?