php获取网址

 #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