An example of php code to obtain the domain name in the URL

<?php
/**
 Url中取主机域名
 http://bbs.it-home.org
*/
function getExt($url){   
$arr = parse_url($url);     
$file = $arr['host'];   
$ext = substr($file,strpos($file,".")+1);   
return $ext;
}

//调用示例
$url="http://www.baidu.com/path.php?arg=value#anchor";
$qa=getExt($url);
var_dump($qa);
?>

<?php  
    // 从 URL 中取得主机名  
    preg_match("/^(http:\/\/)?([^\/]+)/i",  
    " http://www.php.net/index.html", $matches);  
    $host = $matches[2];  
      
    // 从主机名中取得后面两段  
    preg_match("/[^\.\/]+\.[^\.\/]+$/", $host, $matches);  
    echo "domain name is: {$matches[0]}\n";  
?>