$re = '/^(((https?|ftps?):\/\/)|(mailto:))[a-zA-Z0-9\.:\/@-]*$/m';
$str = 'https://www.sample.com
https://www.sample-sample.com
http://www.sample.com
http://www.sample-sample.com
https://sample-sample.com
http://sample-sample.com
ftps://sample-sample.com
ftp://sample-sample.com
ftps://sample.sample.com:3000
ftp://sample.sample.com:3000
http://intranet/index.html
mailto:sample@sample.com
';
preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0);
// Print the entire match result
var_dump($matches);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php