问如何在AngularJS中使用控制器动作设置表单域的值

EN

<div ng:app>
    <form name="myForm" ng-controller="Ctrl">Age:
        <input type="text" data-ng-model="person.age" />
        <br/>First Name:
        <input type="text" data-ng-model="person.first_name" />
        <button ng-click="setFirstName()" type="button">Set First Name</button>
        <br/>Last Name:
        <input type="text" data-ng-model="person.last_name" />
        <button ng-click="setLastName()" type="button">Set Last Name</button>
        <br/>
    </form>
</div>





function Ctrl($scope) {
    $scope.setFirstName = function () {
        $scope.person = {
            first_name: 'King'
        }
    };

    $scope.setLastName = function () {
        $scope.person = {
            last_name: 'Kong'
        }
    };
}