http://www.52dj.com
整个站点的用户跟踪管理都用的session,一般都运行没有问题，可是有时候session莫名其妙的出错，比如这个注销的程序，平时没问题，但有时候就怪了 ，关键在于第一个warning
程序很简单
logout.php
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<?
session_start(); //line 2
session_destroy(); //line 3
header("location:../index.php"); //line 4
?>
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Warning: session_start(): The session id contains invalid characters, valid characters are only a-z, A-Z and 0-9 in /www/users/52dj.cn/user/logout.php on line 2

Warning: session_start(): Cannot send session cookie - headers already sent by (output started at /www/users/52dj.cn/user/logout.php:2) in /www/users/52dj.cn/user/logout.php on line 2

Warning: session_start(): Cannot send session cache limiter - headers already sent (output started at /www/users/52dj.cn/user/logout.php:2) in /www/users/52dj.cn/user/logout.php on line 2

Warning: session_destroy(): Session object destruction failed in /www/users/52dj.cn/user/logout.php on line 3

Warning: Cannot modify header information - headers already sent by (output started at /www/users/52dj.cn/user/logout.php:2) in /www/users/52dj.cn/user/logout.php on line 4