How do I delete PHPSESSID on client computers

Question

UPDATE ON THE PROBLEM:

• On some browsers, we have two PHPSESSIDs.
• One PHPSESSID is not set by me anywhere in my script
• It has

Answer 1

Just provide the 4th argument when calling setcookie function :

setcookie ("PHPSESSID", "", time() - 3600, '/');

Explanation

The 4th argument of the setcookie() function is $path of the session to be set. And for this, "The default value is the current directory that the cookie is being set in.". (See : http://php.net/manual/en/function.setcookie.php.) So if you are calling this function from a file locating in folder "/folder", it will try to delete a cookie from that folder only. By setting the $path to "/" we are telling the function to delete the session_id from the root directory.

I have tested it and it deleted the PHPSESSID from the cookie successfully.