获取客户端ip

<?php//获取客户端ip$onlineip = '';$cip = getenv ( 'HTTP_CLIENT_IP' ); //getenv()从环境中取字符串,获取环境变量的值，用户IP$xip = getenv ( 'HTTP_X_FORWARDED_FOR' ); //浏览当前页面的用户计算机的网关$rip = getenv ( 'REMOTE_ADDR' ); //用户浏览器所在机器的网址$srip = $_SERVER ['REMOTE_ADDR']; //正在浏览当前页面用的IP地址//strcasecmp二进制安全比较字符串（不区分大小写）if ($cip && strcasecmp ( $cip, 'unknown' )) {$onlineip = $cip;} elseif ($xip && strcasecmp ( $xip, 'unknown' )) {$onlineip = $xip;} elseif ($rip && strcasecmp ( $xip, 'unknown' )) {$onlineip = $rip;} elseif ($srip && strcasecmp ( $srip, 'unknown' )) {$onlineip = $srip;}preg_match ( '/[\d\.]{7,15}/', $onlineip, $match );$onlineip = $match [0] ? $match [0] : 'unknown';echo $onlineip;?>