如何在AgularJS中进行单选按钮验证

<div ng-app="myApp" ng-controller="myCtrl">
  <input type="radio" ng-model="selectedOption" value="option1"> Option 1
  <input type="radio" ng-model="selectedOption" value="option2"> Option 2
  <input type="radio" ng-model="selectedOption" value="option3"> Option 3
</div>

var app = angular.module('myApp', []);
app.controller('myCtrl', function($scope) {
  $scope.validateSelection = function() {
    if (!$scope.selectedOption) {
      $scope.selectionError = true;
    } else {
      $scope.selectionError = false;
    }
  };
});

<div ng-app="myApp" ng-controller="myCtrl">
  <input type="radio" ng-model="selectedOption" value="option1"> Option 1
  <input type="radio" ng-model="selectedOption" value="option2"> Option 2
  <input type="radio" ng-model="selectedOption" value="option3"> Option 3
  <button ng-click="validateSelection()">Validate</button>
  <p ng-show="selectionError" style="color: red;">Please select an option.</p>
</div>