PHP CI codeigniter js 类 跳转 弹窗 弹框 对话框 提示 获取 ip地址

<?php if (!defined('BASEPATH')) exit('No direct script access allowed'); 

class Js {
    
    function alert($msg = ''){
        echo "<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />";
        echo "<script>alert('".$msg."');</script>";

    }
    
    function go($url = ''){
        echo "<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />";
        echo "<script>window.top.location='".$url."';</script><noscript>正在为您跳转".$url."，如果您禁止了Javascript,请启用，否则请手工回到主页。感谢！</noscript>";
        exit;
        /*这个位置没有截断输出，会导致继续执行代码！*/
    }
    function get_ip(){
       if (getenv("HTTP_CLIENT_IP") && strcasecmp(getenv("HTTP_CLIENT_IP"), "unknown"))
           $ip = getenv("HTTP_CLIENT_IP");
       else if (getenv("HTTP_X_FORWARDED_FOR") && strcasecmp(getenv("HTTP_X_FORWARDED_FOR"), "unknown"))
           $ip = getenv("HTTP_X_FORWARDED_FOR");
       else if (getenv("REMOTE_ADDR") && strcasecmp(getenv("REMOTE_ADDR"), "unknown"))
           $ip = getenv("REMOTE_ADDR");
       else if (isset($_SERVER['REMOTE_ADDR']) && $_SERVER['REMOTE_ADDR'] && strcasecmp($_SERVER['REMOTE_ADDR'], "unknown"))
           $ip = $_SERVER['REMOTE_ADDR'];
       else
           $ip = "unknown";
           
       $tmp = explode(',', $ip);
       if (count($tmp)>1){
           $ip = $tmp[0];
       }
       $len = strlen($ip);
       if ($len>15){
           $ip = substr($ip,0,15);
       }
       return $ip;
    }
}