Close the browser will not automatically destroy the PHP session, depending on the session configuration. 1. By default, PHP uses session cookies without expiration time. Close the browser will delete the cookie, but the server-side session data still exists until it is cleaned up by the garbage collection mechanism; 2. If the expiration time of the cookie is manually set, closing the browser will not delete the cookie, and the user can still resume the session the next time he accesses; 3. To ensure that closing the browser ends the session, the default behavior or explicitly clear the cookie and session data; 4. Server-side cleanup is not instant, and it depends on configuration parameters such as session.gc_maxlifetime and the garbage collection mechanism. Therefore, placing session settings rationally and implementing logout logic can effectively manage the session life cycle.

Closing the browser doesn't automatically destroy a PHP session — it depends on how the session is configured.

PHP sessions are usually managed using cookies, and whether closing the browser ends the session depends on whether the session cookie has an expiration time set. Here's how it works in more detail:

How PHP Sessions Work with Cookies

When you start a session in PHP using session_start() , the server creates a unique session ID for that user and sends it to the browser as a cookie. By default, this cookie is a session cookie , meaning it doesn't have an explicit expiration time and will be deleted when the browser is closed.

However:

• If you manually set an expiration time for the session cookie (using setcookie() or session_set_cookie_params() ), then the session may persist even after the browser is closed.
• The session data itself is stored on the server, and it's only removed after a certain amount of time passes without any activity (based on garbage collection settings).

What Happens When You Close the Browser?

• If the session cookie is a temporary (session) cookie :
  Closing the browser deletes the session ID from the client side. The next time the user visits the site, they'll get a new session ID, and the old session data will still exist on the server until it's cleaned up by the garbage collector.

  

• If the session cookie has an expiration time (like for "Remember Me" features):
  Closing the browser doesn't delete the cookie. When the user comes back, the same session ID is sent back to the server, and the previous session may still be active if it hasn't expired server-side.

So, simply closing the browser doesn't guarantee the session is destroyed — it just removes the way the browser remembers the session ID.

How to Make Sure a Session Ends When the Browser Closes

If you're building a login system and want sessions to end when the browser closes (for security reasons), here's what you can do:

• Don't set an expiration time on the session cookie.
• Use default PHP session behavior, which uses session cookies.
• Optionally, you can explicitly clear session data when the user logs out using:
  • session_destroy() – to delete session data on the server
  • setcookie(session_name(), '', time()-1, '/') – to delete the session cookie on the client

This setup ensures that once the browser is closed, the session ID won't persist, and the user will need to log in again.

Server-Side Cleanup Isn't Immediate

Even if the browser is closed and the session cookie is gone, the session file or database entry on the server might not be deleted right away. PHP relies on a garbage collection process that runs occasionally.

Some things that affect cleanup:

• The value of session.gc_maxlifetime in your PHP config
• The probability and divisor values ??( session.gc_probability , session.gc_divisor )
• Whether the session storage mechanism supports automatic cleanup

In short:

• A closed browser often breaks the connection to the session, but doesn't always erase the session immediately.
• If you want to ensure sessions don't linger, implement proper logo logic and configure session settings appropriately.

Basically that's it.

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