使用Bootstrap 4中的第二个按钮关闭模式

<button type="button" class="btn btn-primary" data-toggle="modal" data-target="#myModal">
  打开模态框
</button>

<div class="modal" id="myModal">
  <div class="modal-dialog">
    <div class="modal-content">
    
      <!-- 模态框头部 -->
      <div class="modal-header">
        <h4 class="modal-title">模态框标题</h4>
        <button type="button" class="close" data-dismiss="modal">&times;</button>
      </div>
      
      <!-- 模态框主体 -->
      <div class="modal-body">
        <p>模态框内容...</p>
      </div>
      
      <!-- 模态框底部 -->
      <div class="modal-footer">
        <button type="button" class="btn btn-secondary" data-dismiss="modal">关闭</button>
      </div>
      
    </div>
  </div>
</div>