Alternative to
[http://snipplr.com/view/12616/strip-url-to-its-domain-name/](http://snipplr.com/view/12616/strip-url-to-its-domain-name/, "this snippet"), as it didn't come out clearly in the comments.

Update - Edited based on gdvickery's comment - thanks!

Also added a test case so people can see how it works.