Edit in JSFiddle

angular.module('MyModule', [])
    .controller('MyController', function ($scope) {
    $scope.callAlert = function (data) {
        alert(data);
    };
});
document.getElementById('outsideController').onclick = function(){ 
   angular.element(document.getElementById('testDiv')).scope().callAlert('click-B');
};
<div id="testDiv" ng-app='MyModule' ng-controller="MyController">
    <a href="#" ng-click="callAlert('click-A')">클릭 A</a>
</div>
<a href="#" id="outsideController">클릭 B</a>