PHP获取当前用户真实的IP

function getIp(){$onlineip='';if(getenv('HTTP_CLIENT_IP')&&strcasecmp(getenv('HTTP_CLIENT_IP'),'unknown')){$onlineip=getenv('HTTP_CLIENT_IP');} elseif(getenv('HTTP_X_FORWARDED_FOR')&&strcasecmp(getenv('HTTP_X_FORWARDED_FOR'),'unknown')){$onlineip=getenv('HTTP_X_FORWARDED_FOR');} elseif(getenv('REMOTE_ADDR')&&strcasecmp(getenv('REMOTE_ADDR'),'unknown')){$onlineip=getenv('REMOTE_ADDR');} elseif(isset($_SERVER['REMOTE_ADDR'])&&$_SERVER['REMOTE_ADDR']&&strcasecmp($_SERVER['REMOTE_ADDR'],'unknown')){$onlineip=$_SERVER['REMOTE_ADDR'];}return $onlineip;}