php获取外网IP----百篇之一

<?php
function getIp(){
$ip = '';
if(isset($_SERVER['HTTP_X_FORWARDED_FOR'])){
$ip = $_SERVER['HTTP_X_FORWARDED_FOR'];
}elseif(isset($_SERVER['HTTP_CLIENT_IP'])){
$ip = $_SERVER['HTTP_CLIENT_IP'];
}else{
$ip = $_SERVER['REMOTE_ADDR'];
}
$ip_arr = explode(',', $ip);
return $ip_arr[0];
}
$a= getIp();
echo $a;
?>