<?php/** * @Author: Ding Jianlong * @Date:  2019-03-07 16:14:04 * @Last Modified by:  Ding Jianlong * @Last Modified time: 2019-03-20 13:45:12 */header('content-type:text/html;charset=utf-8');//獲取頂級域名function getTopHost($url){ $url = strtolower($url);  //首先轉成小寫 $hosts = parse_url($url); $host = $hosts['host']; //查看是幾級域名  $data = explode('.', $host);  $n = count($data);  //判斷是否是雙后綴  $preg = '/[/w].+/.(com|net|org|gov|edu)/.cn$/';  if(($n > 2) && preg_match($preg,$host)){   //雙后綴取后3位   $host = $data[$n-3].'.'.$data[$n-2].'.'.$data[$n-1];  }else{   //非雙后綴取后兩位   $host = $data[$n-2].'.'.$data[$n-1];  }  return $host;}// 測試echo getTopHost("http://ABC.com/s/j?wd=djl"),'<br>';echo getTopHost("http://www.abc.com/s/j?wd=djl"),'<br>';echo getTopHost("http://2.www.abc.com/s/j?wd=djl"),'<br>';echo getTopHost("https://mp.weixin.qq.com/s?__biz=MzA3ODI3ODUzMw=="),'<br>';echo getTopHost("http://www.49028c.com/"),'<br>';echo getTopHost("http://www.zzvips.com/"),'<br>';echo getTopHost("https://www.sina.com.cn/?from=kandian"),'<br>';