php获取ip地址-完整版

/***  @Explain:  获取IP地址*/function getIP(){   if ($HTTP_SERVER_VARS["HTTP_X_FORWARDED_FOR"]) {       $ip = $HTTP_SERVER_VARS["HTTP_X_FORWARDED_FOR"];    }    elseif ($HTTP_SERVER_VARS["HTTP_CLIENT_IP"]) {       $ip = $HTTP_SERVER_VARS["HTTP_CLIENT_IP"];    }   elseif ($HTTP_SERVER_VARS["REMOTE_ADDR"]) {       $ip = $HTTP_SERVER_VARS["REMOTE_ADDR"];    }    elseif (getenv("HTTP_X_FORWARDED_FOR")) {       $ip = getenv("HTTP_X_FORWARDED_FOR");    }    elseif (getenv("HTTP_CLIENT_IP")) {       $ip = getenv("HTTP_CLIENT_IP");    }    elseif (getenv("REMOTE_ADDR")) {       $ip = getenv("REMOTE_ADDR");    }    else {       $ip = "Unknown";    }   return $ip;}