1.class 中间有空格 .layui-icon.layui-icon-face-smile-b 可以使用句号（.）隔开每个 class 名称
<i class="layui-icon layui-icon-face-smile-b" style="color:deeppink;"></i>
2.多个相同相似，中的第一个或某个 #title111 > tr:nth-child(1) >td:nth-child(1)
<id="title111">
<tr>
<td width="90" align="center">a</td>
<td width="150" align="center">b</td>
<td width="100" align="center">c</td>
<td width="260" align="center">d</td>
<td width="100" align="center">e</td>
<td width="130" align="center">f</td>
</tr>
3.没有class和id定位[layuimini-href="/FlowManage/Flowinstance/DoneFlow_FK"]
<a href="javascript:;" layuimini-href="/FlowManage/Flowinstance/DoneFlow_FK" target="_self">
标签：layui,selector,nth,child,class,icon From： https://www.cnblogs.com/yin-jing/p/17888231.html