$domain = $_SERVER['HTTP_HOST'];
echo $domain;

$protocol = isset($_SERVER['HTTPS']) && $_SERVER['HTTPS'] === 'on' ? 'https://' : 'http://';
$domain = $_SERVER['HTTP_HOST'];
$current_url = $protocol . $domain;
echo $current_url;

<?
//獲取當前的域名:
echo $_SERVER['SERVER_NAME'];
//獲取來源網(wǎng)址,即點擊來到本頁的上頁網(wǎng)址
echo $_SERVER["HTTP_REFERER"];
$_SERVER['REQUEST_URI'];//獲取當前域名的后綴
$_SERVER['HTTP_HOST'];//獲取當前域名
dirname(__FILE__);//獲取當前文件的物理路徑
dirname(__FILE__)."/../";//獲取當前文件的上一級物理路徑
?>

<?php
//獲取域名或主機地址
echo $_SERVER['HTTP_HOST']."<br />";
//獲取網(wǎng)頁地址
echo $_SERVER['PHP_SELF']."<br />";
//獲取網(wǎng)址參數(shù)
echo $_SERVER["QUERY_STRING"]."<br />";
//獲取用戶代理
echo $_SERVER['HTTP_REFERER']."<br />";
//獲取完整的url
echo 'http://'.$_SERVER['HTTP_HOST'].$_SERVER['REQUEST_URI'];
echo 'http://'.$_SERVER['HTTP_HOST'].$_SERVER['PHP_SELF'].'?'.$_SERVER['QUERY_STRING'];
//包含端口號的完整url
echo 'http://'.$_SERVER['SERVER_NAME'].':'.$_SERVER["SERVER_PORT"].$_SERVER["REQUEST_URI"];
//只取路徑
$url='http://'.$_SERVER['SERVER_NAME'].$_SERVER["REQUEST_URI"];
echo dirname($url);
?>