bootstrap4里的模态窗口modal

基本例子：

<div class="modal fade" id="Modal">
    <div class="modal-dialog">
        <div class="modal-content">
            <div class="modal-header">
                <h5 class="modal-title">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">你好，世界</div>
            <div class="modal-footer">底部信息</div>
        </div>
    </div>
</div>

官方文档链接：https://v4.bootcss.com/docs/components/modal/