<!DOCTYPE html> <html lang="zh"> <head> <meta charset="UTF-8" /> <title>css实现九宫格</title> <style type="text/css"> .box{width:333px;} .box div{ width:100px;height:100px;border:3px solid blue;float:left;background: green; margin-left:-3px; margin-top:-3px; } .box div:hover{ position: relative; border-color:red; z-index: 100; } </style> </head> <body> <div id="wrap"> <div class="box"> <div></div> <div></div> <div></div> <div></div> <div></div> <div></div> <div></div> <div></div> <div></div> </div> </div> </body> </html>