无法使用selenium自动化警报框

Question

我有一个用于保存表单更改的警告框。但是，我无法使用selenium自动化警报框。这是一个image of the Alert box。我已经使用过像这样的方法：

   driver.switchTo().alert().accept();

但这也行不通。

警报的HTML代码：

<div id="ngdialog2" class="ngdialog ngdialog-theme-default ng-scope" role="alertdialog" aria-labelledby="ngdialog2-aria-labelledby" aria-describedby="ngdialog2-aria-describedby">
   <div class="ngdialog-overlay" />
   <div class="ngdialog-content" role="document">
      <div class="ngdialog-message">
         <div class="dialog-header clearfix">
            <h3 id="ngdialog2-aria-labelledby" class="ng-binding">Confirm</h3>
         </div>
         <div class="dialog-content">
            <p id="ngdialog2-aria-describedby" class="ng-binding">Do you want to save?</p>
         </div>
         <div class="button-controls">
            <button class="button cancel-btn ng-binding" ng-click="closeThisDialog(false)">No</button>
            <button class="button btn-submit ng-binding" ng-click="closeThisDialog(true)">Yes</button>
         </div>
      </div>
   </div>
</div>