<?php
function is_valid_domain_name($domain_name)
{
return (preg_match("/^([a-z\d](-*[a-z\d])*)(\.([a-z\d](-*[a-z\d])*))*$/i", $domain_name) //valid chars check
&& preg_match("/^.{1,253}$/", $domain_name) //overall length check
&& preg_match("/^[^\.]{1,63}(\.[^\.]{1,63})*$/", $domain_name) ); //length of each label
}
?>
测试用例:
is_valid_domain_name? [a] Y
is_valid_domain_name? [0] Y
is_valid_domain_name? [a.b] Y
is_valid_domain_name? [localhost] Y
is_valid_domain_name? [google.com] Y
is_valid_domain_name? [news.google.co.uk] Y
is_valid_domain_name? [xn--fsqu00a.xn--0zwm56d] Y
is_valid_domain_name? [goo gle.com] N
is_valid_domain_name? [google..com] N
is_valid_domain_name? [google.com ] N
is_valid_domain_name? [google-.com] N
is_valid_domain_name? [.google.com] N
is_valid_domain_name? [<script] N
is_valid_domain_name? [alert(] N
is_valid_domain_name? [.] N
is_valid_domain_name? [..] N
is_valid_domain_name? [ ] N
is_valid_domain_name? [-] N
is_valid_domain_name? [] N