php显示ip地址的类

<?php
class ip{
	function showIp(){
		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;
	}//function
}//class
$ip=new ip();
echo $ip->showIP();
?>