<div class="Bg01">
<ul>
<li class="Bold">黑域名告警</li>
<li>总数：<span class="Mycolor">24条</span></li>
<li>未处理：<span class="Myred">03条</span></li>
</ul>
</div>
想获取上面class=“Bold”的元素，写法如下
：$(this).children("ul").children("li:first-child").css("color","#FF6666");