Cannot modify header information - headers already sent

Tim356 · #1 (**permalink**) Aug 7th, 2005, 13:43

I've just knocked up a quick login system using cookies and when I run my logout script I get this error:

Quote:

Warning: Cannot modify header information - headers already sent by (output started at c:\inetpub\wwwroot\iponder\dev\afs\logout.php:4) in c:\inetpub\wwwroot\iponder\dev\afs\logout.php on line 8

Warning: Cannot modify header information - headers already sent by (output started at c:\inetpub\wwwroot\iponder\dev\afs\logout.php:4) in c:\inetpub\wwwroot\iponder\dev\afs\logout.php on line 9
Logged Out

here is my logout script:

Code: Select all

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<?PHP

if (isset($_COOKIE['loggedin']))
{
  setcookie ("loggedin", "", time() - 3600);
  setcookie ("mysite_username","");
echo "Logged Out";
} 

$url = "login.htm";
$delay = "2";

echo '<meta http-equiv="refresh" content="'.$delay.';url='.$url.'">';
?>
<title>Untitled Document</title>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">


</head>

<body>
</body>
</html>

I know it's not real secure, but ignoring that, can anyone explain to me what this error means and how I can fix it?[/quote]

Webforumz Staff · #2 (**permalink**) Aug 7th, 2005, 18:42

A cookie is sent via HTTP headers. Unfortunately HTTP headers are sent before any page content and you clearly send some HTML before you try to send the cookie.

Most scripts get around this by doing any checks and sending cookies before the HTML, or using template systems which bypass the problem entirely.

Tim356 · #3 (**permalink**) Aug 7th, 2005, 22:58

Ahhh... I understand now! Thanks Karl, it's fixed.

I will never comment about the donkey again (well...I can't promise that).

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Cannot modify header information - headers already sent