I want to auto-magically change the color of a URL in the middle

Found on the digitalpoint forums at http://forums.digitalpoint.com/showthread.php?t=687808

I want to auto-magically change the color of a URL in the middle, like this

domain_name.com

There is no www so the period can be used as delimiter. The URL is generated by PHP so I can not simply use HTML.

See the Solution using Regular Expressions