I haven't been able to find this one and what I'm trying isn't quite working out for me.

I want to match only domains that:

• don't contain a protocol (http, https, ftp)


• optionally include a subdomain


• don't start with a hyphen but can contain a hyphen

Example domains that would match:

• domain.com


• example.domain.com


• example.domain-hyphen.com


• www.domain.com


• example.museum

Example domains that would not match:

• http://example.com


• subdomain.-example.com


• example.com/parameter


• example.com?anything


• www.subdomain.domain.com

What I've currently got:

/^(?!://)(^[a-zA-Z0-9])?.[a-zA-Z0-9-]+.[a-zA-Z]{2,6}?$/i

It's not matching protocols, allowing hyphen inside the domain, not allowing trailing characters after the TLD, and is allowing a subdomain (but only 1 character).

I still need to allow subdomains of any length, not allow www.subdomain.domain.com and not allow a leading hyphen.