<!DOCTYPE html><html>?<head>??<meta charset="UTF-8">??<title></title>??<style>??*{???margin:0 auto;???padding: :0;??}??body,ul,li{???margin:0;???padding: 0;?????}??li{???list-style: none;??}??a:link,a:visited{???text-decoration: none;??}??a:hover{???text-decoration: underline;??}??#outer{??????????????}??#skin,#nav{???overflow: hidden;??}??#skin li{???float:left;???width:6px;???height:6px;???cursor:pointer;???overflow:hidden;???margin-right:10px;???text-indent:-9999px;???border-width:4px;???border-style:solid;??}??#skin li.current{???background:#fff!important;???}??#red{???border-color:red;???background:red;??}??#green{???border-color:green;???background:green;??}??#black{???border-color:black;???background: black;??}??#nav{???border:1px solid #fff;??}??#nav li{???float:left;???text-align:center;???border-right:1px solid #fff;???color:#fff;??}???????</style>??<script>??????????</script>?</head>?<body>??<div id = "outer">???<ul id ="skin">????<li id="red" class title="紅色">紅</li>????<li id="green" class title="綠色">綠</li>????<li id="black" class = "current" title="黑色">黑</li>???</ul>???<ul id = "nav">????<li><a href="javascript:;">新聞</a></li>????<li><a href="javascript:;">娛樂</a></li>????<li><a href="javascript:;">體育</a></li>????<li><a href="javascript:;">音樂</a></li>????<li class="last"><a href="javascript:;">旅游</a></li>???????</ul>??</div>?????</ul>?</body></html>這里我沒有給outer設(shè)置寬度，不定寬下無法居中，想知道為什么margin：0，auto為什么不生效
不定寬元素為什么不能用margin：0 auto居中
qq_命運(yùn)之骰_0
2018-08-03 21:12:04
