如何使用ng-option在<select>标记内添加搜索框

<script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.7.9/angular.min.js"></script>

<div ng-app="myApp" ng-controller="myCtrl">
  <select ng-model="selectedItem" ng-options="item as item.name for item in items | filter:search">
    <option value="">请选择</option>
  </select>
</div>

var app = angular.module('myApp', []);
app.controller('myCtrl', function($scope) {
  $scope.items = [
    {id: 1, name: '选项1'},
    {id: 2, name: '选项2'},
    {id: 3, name: '选项3'},
    // 其他选项...
  ];
});

app.filter('search', function() {
  return function(items, searchText) {
    var filtered = [];
    angular.forEach(items, function(item) {
      if (item.name.toLowerCase().indexOf(searchText.toLowerCase()) !== -1) {
        filtered.push(item);
      }
    });
    return filtered;
  };
});