php获取访问的ip

function getip(){
if(isset($_SERVER['HTTP_X_FORWARDED_FOR'])){
$online_ip = $_SERVER['HTTP_X_FORWARDED_FOR'];
}elseif(isset($_SERVER['HTTP_CLIENT_IP'])){
$online_ip = $_SERVER['HTTP_CLIENT_IP'];
}else{
$online_ip = $_SERVER['REMOTE_ADDR'];
}
return $online_ip;
}