<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <title>margin-top无效</title> </head> <style> body{ padding:0; margin:0; background:#cccccc;} .box1{ width:500px; margin:0 auto; background:yellow; overflow:hidden;} .box2{ width:100px; height:100px; border:1px #000 solid; margin-top:10px;} </style> <body> <div class="box1"> <div class="box2">box2</div> box1 </div> </body> </html>
ie6下：
谷歌下：
解决方法：
在外层样式加：overflow:hidden;
