//获取域名或主机地址 
echo $_SERVER['HTTP_HOST']."<br>";#localhost //获取网页网址
echo $_SERVER['PHP_SELF']."<br>"; //获取网址参数
echo $_SERVER['QUERY_STRING']."<br>"; //获取用户代理
echo $_SERVER['HTTP_REFERER']."<br>"; //获取完整的url
echo 'http://'.$_SERVER['HTTP_HOST'].$_SERVER['REQUEST_URI']."<br>"; echo 'http://'.$_SERVER['HTTP_HOST'].$_SERVER['PHP_SELF'].'?'.$_SERVER['QUERY_STRING']."<br>"; //包含端口号的完整url
echo 'http://'.$_SERVER['SERVER_NAME'].':'.$_SERVER["SERVER_PORT"].$_SERVER["REQUEST_URI"]."<br>"; //只取路径
$url='http://'.$_SERVER['SERVER_NAME'].$_SERVER["REQUEST_URI"]; echo dirname($url);