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

It is mentioned here, though Use of session_register() is deprecated and Use of $_SESSION is preferred : -

If session_start() was not called before this function is called, an implicit call to session_start() with no parameters will be made. $_SESSION does not mimic this behavior and requires session_start() before use.

Then, using $_SESSION , append a JSON file with Auth=True, with TimeOut=20 minutes.
Whenever, user logs out or after timeout, set Auth=False. Then, read that JSON file using PHP and

Then, if Auth=False, create JS using PHP that OnLoad event, document.cookie = 'PHPSESSID' + '=;expires=Thu, 01 Jan 1970 00:00:01 GMT;';