充值金额选择器示例

<div ng-app="myApp" ng-controller="rechargeCtrl">
  <h4>选择充值金额(USD)：</h4>
  <select ng-model="selectedAmount">
    <option ng-value="50">基础包 $50</option>
    <option ng-value="200">商务包 $200</option>
    <option ng-value="500">企业包 $500</option>
  </select>
  
  <div ng-show="selectedAmount">
    您已选择：<strong>{{ selectedAmount }}</strong> 美元
  </div>
</div>

<script>
angular.module('myApp', [])
.controller('rechargeCtrl', function($scope) {
  $scope.selectedAmount = 50; // 默认选中
});
</script>