//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'];
	 
	//包含端口号的完整url
	echo 'http://'.$_SERVER['SERVER_NAME'].':'.$_SERVER["SERVER_PORT"].$_SERVER["REQUEST_URI"]; 
	 
	//只取路径
	$url='http://'.$_SERVER['SERVER_NAME'].$_SERVER["REQUEST_URI"]; 
	echo dirname($url)
	 
                            
                        
                        
                        
                        
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