how do I stop user SESSION from logging out?

[tomm098]

Hey, I have this $_SESSION code, across all my pages, however I was wondering how to make it so the browser remembers the user, and they do not have to login everytime they come back to my website. Just like how you are always logged into this site. Here is my PHP code:

 

<?php
//initialize the session
if (!isset($_SESSION)) {
  session_start();
}

// ** Logout the current user. **
$logoutAction = $_SERVER['PHP_SELF']."?doLogout=true";
if ((isset($_SERVER['QUERY_STRING'])) && ($_SERVER['QUERY_STRING'] != "")){
  $logoutAction .="&". htmlentities($_SERVER['QUERY_STRING']);
}

if ((isset($_GET['doLogout'])) &&($_GET['doLogout']=="true")){
  //to fully log out a visitor we need to clear the session varialbles
  $_SESSION['MM_Username'] = NULL;
  $_SESSION['MM_UserGroup'] = NULL;
  $_SESSION['PrevUrl'] = NULL;
  unset($_SESSION['MM_Username']);
  unset($_SESSION['MM_UserGroup']);
  unset($_SESSION['PrevUrl']);

  $logoutGoTo = "../index.php";
  if ($logoutGoTo) {
    header("Location: $logoutGoTo");
    exit;
  }
}
?>

[trq]

You'll need to use cookies.

[tomm098]

Do you know how I would go about doing that? I'm not sure where to even start using cookies?