how to find our the extention of a domain name

[xiaodao]

hi
how do you find out the extention of a domain name?
thanks

[ralph l mayo]

PHP Code:

preg_match('/.*\.(.*)/', 'del.icio.us', $tld);
echo $tld[1]; // us 


Is this what you mean?

[xiaodao]

what i want is actually for example
yayaya.com
i want to find out its extention is .com not .net or .org

[ralph l mayo]

edit for a better regex that matches things like co.uk (still kinda flawed)

PHP Code:

$domain = 'www.example.com';
preg_match('/\.([a-zA-Z]{2,3}\.[a-zA-Z]{2}|[a-zA-Z]{2,4})$/', $domain, $tld);
print_r($tld); 


[xiaodao]

well, how to build a function to check com,net,org,us,info,cc,com.sg?

[Velox Letum]

PHP Code:

<?php
function get_tld($url) {
     $url = parse_url($url);
     return substr($url['host'], strripos($url['host'], '.') + 1);
}
echo get_tld('http://foo.com/bar.php?foobar=barfoo'); // Returns 'com' (without quotes).
?>

[Element]

In addition to your problem, using Velox's code...

PHP Code:

<?php 
function valid_tld($url) {
     $valid_tld = array('com', 'net', 'org'); // Valid TLDs 
     $url = parse_url($url); // URL parts
     $tld = substr($url['host'], strripos($url['host'], '.') + 1); // TLD 
     if(in_array($tld, $valid_tld)) { return true; } else { return false; }
} 

if(valid_tld("http://example.com/index.php?a=a&b=b")) {
  echo "Valid domain!";
}

?>