27.5.3　登出

我们可以已经注意到了，在图27-6所示的菜单选项上有一个标有"logout"的链接。该链接指向脚本logout.php。程序清单27-14给出了它的源代码。

程序清单27-14　logout.php——该脚本将结束一个用户会话

＜?php

//include function files for this application

require_once('bookmark_fns.php');

session_start();

$old_user=$_SESSION['valid_user'];

//store to test if theywerelogged in

unset($_SESSION['valid_user']);

$result_dest=session_destroy();

//start output html

do_html_header('Logging Out');

if(!empty($old_user)){

if($result_dest){

//if they were logged in and are now logged out

echo'Logged out.＜br/＞';

do_html_url('login.php','Login');

}else{

//they were logged in and could not be logged out

echo'Could not log you out.＜br/＞';

}

}else{

//if they weren't logged in but came to this page somehow

echo'You were not logged in,and so have not been logged out.＜br/＞';

do_html_url('login.php','Login');

}

do_html_footer();

?＞

我们会发现这段代码有些熟悉。因为它是根据第23章中编写的源代码而修改的。