取得使用者的IP位址 - PHP

原本使用$_SERVER['REMOTE_ADDR']，卻遇到使用者在Proxy Server底下，這只會取得Proxy Server的IP，既然如此只好換個方式了。

<?php 
$userIP = null; 
if(!empty($_SERVER['HTTP_CLIENT_IP'])){ 
    $userIP = $_SERVER['HTTP_CLIENT_IP']; 
}else if(!empty($_SERVER['HTTP_X_FORWARDED_FOR'])){ 
    $userIP = $_SERVER['HTTP_X_FORWARDED_FOR']; 
}else{ 
    $userIP = $_SERVER['REMOTE_ADDR']; 
}  
echo $userIP; 
?>

提供給大家當作參考囉！