Angular JS - Exposing Controller Function outside the module via onClick function call

Exposing Controller Function outside the module via onClick function call For re-using already defined onClick functions

HTML

<link rel="stylesheet" href="http://netdna.bootstrapcdn.com/bootstrap/3.0.0/css/bootstrap.min.css">
<button onclick="call()">Call Controller's method from outside</button>
<div  id="container" ng-app="" ng-controller="testController">
</div>

JavaScript

function call() {
    var scope = angular.element(document.getElementById('container')).scope();
      scope.$apply(function(){
        scope.msg = scope.msg + ' I am the newly addded message from the outside of the controller.';
    })
    alert(scope.returnHello());
}

function testController($scope) {
    $scope.msg = "Hello from a controller method.";
    $scope.returnHello = function() {
        return $scope.msg ; 
    }
}