Four examples of php global variable $_SERVER

This article introduces an example of the global variable $_SERVER in PHP. Friends in need can refer to it.

Example 1, loop to list the values ​​in the global variable $_SERVER

<?php
foreach ($_SERVER as $var => $value) {
   echo "$var => $value <br />";
}
?>

Example 2, get the last update time of the file

<?php
  
  $lastmod = filemtime($_SERVER['SCRIPT_FILENAME']);

  echo '此文件的最后更新时间 '
        . date('l d F Y, \a\t H:i:s T', $lastmod)
        . '.';
?>

Example 3, get the update date and time of the file

<?php 
$lastmod = filemtime($_SERVER['SCRIPT_FILENAME']); 

echo '文件更新时间：' . date('l d F Y, \a\t H:i:s T', $lastmod); 
?>

Example 4, site environment variable information

<?php
$version = $_SERVER['SITE_VERSION'];

if ('members' == $version) {
    if (!authenticate_user($_POST['username'], $_POST['password'])) {
        header('Location: http://bbs.it-home.org/');
        exit;
    }
}
include_once "${version}_header"; //加载版本头信息