PHP中获取当前页面的完整URL

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://www.lemont.cn/home/index.php?id=1

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

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

//获取网址参数 
echo $_SERVER["QUERY_STRING"]."<br>"; #id=1

//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://www.lemont.cn/home/index.php?id=1

//包含端口号的完整url
echo 'http://'.$_SERVER['SERVER_NAME'].':'.$_SERVER["SERVER_PORT"].$_SERVER["REQUEST_URI"]; 
#http://www.lemont.cn:80/home/index.php?id=1

//只取路径
$url='http://'.$_SERVER['SERVER_NAME'].$_SERVER["REQUEST_URI"]; 
echo dirname($url);
#http://www.lemont.cn:80/home