所以我试图在我的网站中通过facebook集成登录。因为不希望使用facebook的人可以使用我们网站的登录系统，我们创建了一种设置cookie和会话的方法。我还想为cookies用户创建session和facebook个变量。
但是，我收到了这个错误：
Warning: Cannot modify header information - headers already sent by (output started at /home/content/88/10590088/html/Test4/index.php:9) in /home/content/88/10590088/html/Test4/login.php on line 144
Warning: Cannot modify header information - headers already sent by (output started at /home/content/88/10590088/html/Test4/index.php:9) in /home/content/88/10590088/html/Test4/login.php on line 145
和第145行和第144行是下面的最后两行：
// CREATE THEIR SESSIONS AND COOKIES
$_SESSION['userid'] = $db_id;
$_SESSION['username'] = $db_username;
setcookie("id", $db_id, strtotime( '+30 days' ), "/", "", "", TRUE);
setcookie("user", $db_username, strtotime( '+30 days' ), "/", "", "", TRUE);