Validating URLs with an underscore in the subdomain.

[scotthovestadt]

Currently, the URL parsing fails for any URL that includes a subdomain with an underscore. For example: my_domain.scott.com

This isn't a completely straightforward issue, because technically underscores in subdomains aren't standards compliant -- even if it's used and tends to work in every browser.

@yuyang041060120 Would you accept a pull request to allow for underscores in the subdomain?

[kevindqc]

The regex seems pretty restrictive in what it allows :(

http://localhost:11795/ for example is not considered a valid URL, neither would http://machinename/ be.

telnet://whatever.com/ wouldn't be considered a valid URL either since the regex seems to restrict the protocol to http/s and ftp.

[matthewswallace]

localhost should be added. I'm running into a situation where I need this.