<!DOCTYPE html> <html> <head> <meta charset="UTF-8"> <title></title> <script src="js/jquery-1.7.min.js" type="text/javascript" charset="utf-8"></script> </head> <style type="text/css"> .div{ width: 500px; height: 300px; background-color: red; position: absolute; left: 50%; top:50%; margin: -150px 0px 0px -250px; } </style> <body> <div class="div"> </div> </body> </html>