PHP中的页面重新加载检测在Xampp中有效，但在Apache2.2.22中没有

I have been trying to detect the page reload/refresh in php using both Xampp and Apache 2.2.22 using PHP. It workd fine in Xampp but not using Apache 2.2.22( on my UNIX environment)

<?php
// Start the session
    session_start();
    $RequestSignature = md5($_SERVER['REQUEST_URI'].$_SERVER['QUERY_STRING'].print_r($_POST, true));

    if (isset ($_SESSION['LastRequest']) && $_SESSION['LastRequest'] == $RequestSignature)
    {
          echo 'This is a refresh.';
    }
 ?>

try dis

$pageWasRefreshed = isset($_SERVER['HTTP_CACHE_CONTROL']) && $_SERVER['HTTP_CACHE_CONTROL'] === 'max-age=0';

if($pageWasRefreshed ) {
   //do something because page was refreshed;
} else {
   //do nothing;
}