AngularJS - Controller As Syntax

HTML

<link rel="stylesheet" href="//netdna.bootstrapcdn.com/twitter-bootstrap/2.3.1/css/bootstrap-combined.min.css">
<script src="http://code.angularjs.org/1.1.5/angular.js"></script>
<div ng-app="myapp">
    <div ng-controller="PersonCtrl as person">
        <p>{{ person.name['last'] }}</p>
    </div>
     <div ng-controller="PersonCtrl2 as person2">
         Change name <button type="button" ng-click="person2.changeName()"> To Ted</button>
     </div>
</div>

JavaScript

var myapp = angular.module('myapp', []);

myapp.controller('PersonCtrl', function (myService1) {
    this.name = myService1.newName;
});

myapp.service('myService1', function() {
    return {newName :{'last': 'Bob'}};
});


var PersonCtrl2 = function(myService1) {
    this.service = myService1;
};

PersonCtrl2.prototype.changeName = function() {
    alert('a');
    this.service.newName.last='Ted';
};

myapp.controller('PersonCtrl2', PersonCtrl2);