建议看一下PHP手册，在PHP4和PHP5中SESSION的一些函数已经发生了变化：Session 函数 Table of Contents session_cache_expire — Return current cache expire session_cache_limiter — Get and/or set the current cache limiter session_commit — session_write_close 的别名 session_decode — Decodes session data from a string session_destroy — Destroys all data registered to a session session_encode — 将当前会话数据编码为一个字符串 session_get_cookie_params — Get the session cookie parameters session_id — Get and/or set the current session id session_is_registered — Find out whether a global variable is registered in a session session_module_name — Get and/or set the current session module session_name — Get and/or set the current session name session_regenerate_id — Update the current session id with a newly generated one session_register — Register one or more global variables with the current session session_save_path — Get and/or set the current session save path session_set_cookie_params — Set the session cookie parameters session_set_save_handler — Sets user-level session storage functions session_start — Initialize session data session_unregister — Unregister a global variable from the current session session_unset — Free all session variables session_write_close — Write session data and end session
建议看一下PHP手册，在PHP4和PHP5中SESSION的一些函数已经发生了变化：Session 函数 Table of Contents session_cache_expire — Return current cache expire session_cache_limiter — Get and/or set the current cache limiter session_commit — session_write_close 的别名 session_decode — Decodes session data from a string session_destroy — Destroys all data registered to a session session_encode — 将当前会话数据编码为一个字符串 session_get_cookie_params — Get the session cookie parameters session_id — Get and/or set the current session id session_is_registered — Find out whether a global variable is registered in a session session_module_name — Get and/or set the current session module session_name — Get and/or set the current session name session_regenerate_id — Update the current session id with a newly generated one session_register — Register one or more global variables with the current session session_save_path — Get and/or set the current session save path session_set_cookie_params — Set the session cookie parameters session_set_save_handler — Sets user-level session storage functions session_start — Initialize session data session_unregister — Unregister a global variable from the current session session_unset — Free all session variables session_write_close — Write session data and end session
例如这个函数：session_is_registered (PHP 4, PHP 5)session_is_registered — Find out whether a global variable is registered in a session说明 bool session_is_registered ( string $name ) Finds out whether a global variable is registered in a session. Warning 自 PHP 5.3.0 起，已经废弃此函数。强烈建议不要应用此函数 。
Table of Contents
session_cache_expire — Return current cache expire
session_cache_limiter — Get and/or set the current cache limiter
session_commit — session_write_close 的别名
session_decode — Decodes session data from a string
session_destroy — Destroys all data registered to a session
session_encode — 将当前会话数据编码为一个字符串
session_get_cookie_params — Get the session cookie parameters
session_id — Get and/or set the current session id
session_is_registered — Find out whether a global variable is registered in a session
session_module_name — Get and/or set the current session module
session_name — Get and/or set the current session name
session_regenerate_id — Update the current session id with a newly generated one
session_register — Register one or more global variables with the current session
session_save_path — Get and/or set the current session save path
session_set_cookie_params — Set the session cookie parameters
session_set_save_handler — Sets user-level session storage functions
session_start — Initialize session data
session_unregister — Unregister a global variable from the current session
session_unset — Free all session variables
session_write_close — Write session data and end session
Table of Contents
session_cache_expire — Return current cache expire
session_cache_limiter — Get and/or set the current cache limiter
session_commit — session_write_close 的别名
session_decode — Decodes session data from a string
session_destroy — Destroys all data registered to a session
session_encode — 将当前会话数据编码为一个字符串
session_get_cookie_params — Get the session cookie parameters
session_id — Get and/or set the current session id
session_is_registered — Find out whether a global variable is registered in a session
session_module_name — Get and/or set the current session module
session_name — Get and/or set the current session name
session_regenerate_id — Update the current session id with a newly generated one
session_register — Register one or more global variables with the current session
session_save_path — Get and/or set the current session save path
session_set_cookie_params — Set the session cookie parameters
session_set_save_handler — Sets user-level session storage functions
session_start — Initialize session data
session_unregister — Unregister a global variable from the current session
session_unset — Free all session variables
session_write_close — Write session data and end session
(PHP 4, PHP 5)session_is_registered — Find out whether a global variable is registered in a session说明
bool session_is_registered ( string $name )
Finds out whether a global variable is registered in a session. Warning
自 PHP 5.3.0 起，已经废弃此函数。强烈建议不要应用此函数 。
我在本地上重新用php4.3.8的环境试了一下, 跟server上的结果是一样的, 没有值返回.4.3下$_SESSION 不是和php5兼容了么....疯了要...