session logout problem in php

In php, if you use session to determine whether the user is logged in or not, you can log out like this:

session_start();
session_destroy();

The session is over. The next sentence should have been js, causing the page to jump.

< script > alert(" Log out!" ); location.href="login.php"; < /script >

If it's a frame page, don't use ES26en directly. Because this can jump inside 1 small frame page, original intention 1 is to want whole frame to jump in the past. So "parent." should be added before location.

The process is as follows (for frame pages only) :

<?php  
session_start();
session_destroy();
// To make the entire page of the framework jump to the landing page 
echo "<script>alert(' Have logged out ');parent.location.href='login.php';</script>";
?>