如何更新Bootstrap Modal内容？

<!-- 触发 Modal 的按钮 -->
<button type="button" class="btn btn-primary" data-toggle="modal" data-target="#myModal">
  打开 Modal
</button>

<!-- Modal -->
<div class="modal fade" id="myModal" tabindex="-1" role="dialog" aria-labelledby="myModalLabel">
  <div class="modal-dialog" role="document">
    <div class="modal-content">
      <div class="modal-header">
        <h5 class="modal-title" id="myModalLabel">Modal 标题</h5>
        <button type="button" class="close" data-dismiss="modal" aria-label="Close">
          <span aria-hidden="true">&times;</span>
        </button>
      </div>
      <div class="modal-body">
        初始内容
      </div>
      <div class="modal-footer">
        <button type="button" class="btn btn-secondary" data-dismiss="modal">关闭</button>
        <button type="button" class="btn btn-primary">保存更改</button>
      </div>
    </div>
  </div>
</div>

// 获取 Modal 元素
var modal = $('#myModal');

// 更新内容
modal.find('.modal-title').html('更新后的标题');
modal.find('.modal-body').html('更新后的内容');

// 打开 Modal
modal.modal('show');