index.php

<?php
session_start();
$period_cookie = 2592000; // 30 дней (2592000 секунд)
 
if($_GET){
    setcookie("utm_source",$_GET['utm_source'],time()+$period_cookie);
    setcookie("utm_medium",$_GET['utm_medium'],time()+$period_cookie);
    setcookie("utm_term",$_GET['utm_term'],time()+$period_cookie);
    setcookie("utm_content",$_GET['utm_content'],time()+$period_cookie);
    setcookie("utm_campaign",$_GET['utm_campaign'],time()+$period_cookie);
}
 
if(!isset($_SESSION['utms'])) {
    $_SESSION['utms'] = array();
    $_SESSION['utms']['utm_source'] = '';
    $_SESSION['utms']['utm_medium'] = '';
    $_SESSION['utms']['utm_term'] = '';
    $_SESSION['utms']['utm_content'] = '';
    $_SESSION['utms']['utm_campaign'] = '';
}
$_SESSION['utms']['utm_source'] = $_GET['utm_source'] ? $_GET['utm_source'] : $_COOKIE['utm_source'];
$_SESSION['utms']['utm_medium'] = $_GET['utm_medium'] ? $_GET['utm_medium'] : $_COOKIE['utm_medium'];
$_SESSION['utms']['utm_term'] = $_GET['utm_term'] ? $_GET['utm_term'] : $_COOKIE['utm_term'];
$_SESSION['utms']['utm_content'] = $_GET['utm_content'] ? $_GET['utm_content'] : $_COOKIE['utm_content'];
$_SESSION['utms']['utm_campaign'] = $_GET['utm_campaign'] ? $_GET['utm_campaign'] : $_COOKIE['utm_campaign'];
?>