Checking for a valid domainname
Very quick function to test a domain name is valid:
function validDomain($domain)
{
// Test domain is actually valid
if (preg_match('/^[a-z]+([a-z0-9-]*[a-z0-9]+)?(.([a-z]+([a-z0-9-]*[a-z0-9]+)?)+)*$/i', $domain))
{
return TRUE;
}
return FALSE;
}
The key here is the regular expression (delimited by the forward slashes at each end):
/^[a-z]+([a-z0-9-]*[a-z0-9]+)?(.([a-z]+([a-z0-9-]*[a-z0-9]+)?)+)*$/
This basically translates ...