top.location.href  //顶级窗口的地址
this.location.href //当前窗口的地址

#测试网址:   http://localhost/blog/testurl.php"<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'].$_SERVER['PHP_SELF'].'"SERVER_PORT"].$_SERVER["REQUEST_URI"];
#http://localhost:80/blog/testurl.php"REQUEST_URI"];
echo dirname($url);
#http://localhost/blog