angularjs – 如何根据angular.js中的子复选框选择父复选框？

我最近一直在玩Angular.js并决定在选中父复选框后检查所有复选框,我已经使用Ng-model和ng-checked指令完成了.

<div ng-app>
        <div ng-controller="Ctrl">
            <input type="checkBox" ng-model="parent"/> SELEct All<br/>
            <input type="checkBox" ng-model="child_1" ng-checked="parent" ng-click="getAllSELEcted()"/> First<br/>
            <input type="checkBox" ng-model="child_2" ng-checked="parent" ng-click="getAllSELEcted()"/> Second<br/>
            <input type="checkBox" ng-model="child_3" ng-checked="parent" ng-click="getAllSELEcted()"/> Three<br/>
            <input type="checkBox" ng-model="child_4" ng-checked="parent" ng-click="getAllSELEcted()"/> Four<br/>
            <input type="checkBox" ng-model="child_5" ng-checked="parent" ng-click="getAllSELEcted()"/> Five<br/>
        </div>
    </div>

现在,我正在尝试选中所有子复选框,一旦检查了所有子复选框但面临一些问题.

function Ctrl($scopE) {
       $scope.getAllSELEcted = function () {
          var chkChild = document.querySELEctorAll('input[ng-model^="child_"]').length;
          var chkChildchecked = document.querySELEctorAll('input[ng-model^="child_"]:checked').length;
          if (chkChild === chkChildchecked) $scope.parent= true;
          else $scope.parent= false;
       }
    }

演示：http://jsfiddle.net/codef0rmer/QekpX/

我们可以使上面的代码更健壮吗？

<input type="checkBox" ng-checked="child_1 && child_2 && child_3 && child_4 && child_5" ng-model="parent"/> SELEct All<br/>