preg_replace to verify phone number

PHP
1

I am trying to use preg_replace to ensure that a telephone number contains numbers only, between 11 and 14 digits, and to eliminate any spaces or brackets() the user might enter.
I have this so far but cant figure out how to set up $pattern.

$okphone = preg_replace($pattern,'',$phone);

Can somebody help please.

2

The PHP to strip out everything but numbers is as follows:


$telephone = '+44 (0)20 1111-2222';
$telephone = preg_replace('/[^0-9]/', '', $telephone);

To check the length, just run it through the strlen function.

3

Thanks!!