Can't logout mysql and php -

I have created a login / logout system in my application but it is not working using session_start () is; , session_destroy (); and session_unset (); etc.

Even I have done so far:

First page (login)

    
 and this is a logout part  
 < Code> & lt ;? Php session_start (); Session_unset (); session_destroy (); Header ("location: index.php"); die;? & Gt;   
 The problem is When clicking on logout button  
 You are using HTTP authentication  
 You are using HTTP authentication.  
 
 Cookies and sessions have no effect on cookies authentication  
.   
 Create another login / logout system, this is not difficult.