<div class="ms-u"></div> <div class="ms-u"></div> <div class="ms-u"></div>
$(".vipCardItem:nth-child(1)").addClass("current");
.ms-u:nth-child(1) {......}
源文：https://blog.csdn.net/luckymaoyy/article/details/53666241
原文：https://www.cnblogs.com/shy1766IT/p/12272557.html