CSS居中绝对定位元素的方法，有很多种，下面是我收集的几种
1，div宽度未知1
<body><div style="position: absolute; left: 50%;"><div style="position: relative; left: -50%; border: dotted red 1px;">没有宽度<br />照样居中，嘿嘿嘿</div></div></body>
demo：/skura23/0123wmsg/
2，div宽度未知2
<div class="outer"><div class="inner">居中<br/>蓄力中</div></div>.outer {position: relative; /* or absolute *//* unnecessary styling properties */margin: 5%;width: 80%;height: 500px;border: 1px solid red;}.inner {position: absolute;left: 50%;top: 50%;transform: translate(-50%, -50%);/* unnecessary styling properties */max-width: 50%;text-align: center;border: 1px solid blue;}
demo：/skura23/6xo11zwv/210/
ps：此方法适合ie8以上的浏览器
3，div宽度已知
<body><div><div id="content">居中蓄力中</div></div></body>#content {position: absolute; left: 0; right: 0; margin-left: auto; margin-right: auto; width: 100px; /* 要设定宽度 */}
![[css] 怎样把一个div居中？怎样把一个浮动元素居中？怎样把绝对定位的div居中？](https://900zi.500zi.com/uploadfile/img/14/889/5f3ac8dba8486a4e8a9af41313d8fb35.jpg)
