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<title>实现下拉菜单效果</title>
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demo.css
*{ margin:0px; padding:0px;}
#menu{ background-color:#eee; width:600px; height:40px; margin:0 auto;}
ul{ list-style:none;}
ul li{ float:left; line-height:40px; text-align:center; position:relative;}
a{ text-decoration:none; color:#000; display:block; width:90px;}
a:hover{ color:#FFF; background-color:#666;}
ul li ul li{ float:none; border-left:none; margin-top:2px; background-color:#eee; }
ul li ul{ display:none; width:90px; position:absolute;}
ul li:hover ul{ display:block;}
效果：
2017-09-06 11:20:46