What's a good regular expression to capture the root domain of a given url?

Question

Using javascript, how can I capture the string example.com from the current domain http://example.com/bar?param=value or https://www.example.com?

My first attempt doesn't work correctly:

https?://w?w?w?[.]?[^?/]

Answer 1

You don't need regex for this! Let the browser parse it for you:

var a = document.createElement('a');
a.href = 'http://foo.com/bar?param=value';
a.hostname; // "foo.com"

Voila!