PHP中获取当前页面的完整URL

<?php 
/**
 * javascript实现：
 * top.location.href   顶级窗口的地址
 * this.location.href  当前窗口的地址
 */


//PHP实现
//测试网址:     http://localhost/blog/testurl.php?id=5 

//获取域名或主机地址 
echo $_SERVER['HTTP_HOST']."<br>";  # localhost

//获取网页地址 
echo $_SERVER['PHP_SELF']."<br>";  # /blog/testurl.php

//获取网址参数 
echo $_SERVER["QUERY_STRING"]."<br>"; # id=5

//获取用户代理 
echo $_SERVER['HTTP_REFERER']."<br>";

//获取完整的url
echo 'http://'.$_SERVER['HTTP_HOST']. $_SERVER['REQUEST_URI'];
echo 'http://'.$_SERVER['HTTP_HOST'].$_SERVER ['PHP_SELF'].'?'.$_SERVER['QUERY_STRING'];
#http://localhost/blog/testurl.php?id=5 

//包含端口号的完整url
echo 'http://'.$_SERVER['SERVER_NAME'].':'.$_SERVER ["SERVER_PORT"].$_SERVER["REQUEST_URI"];
#http://localhost:80/blog/testurl.php?id=5 

//只取路径
$url ='http://'.$_SERVER['SERVER_NAME']. $_SERVER["REQUEST_URI"];
echo dirname ($url);
#http://localhost/blog