How to get base domain from the URL in JavaScript

Question

I would like to extract the base domain from the url in javascript. For example for the list of urls listed below I need to get google.com (or googl

Answer 1

This depends on just how rigorous you need to be. The full list of valid top-level domains is given here, but the rules given here are possibly more helpful.

A simple, probably incomplete regex:

/[-\w]+\.(?:[-\w]+\.xn--[-\w]+|[-\w]{3,}|[-\w]+\.[-\w]{2})$/i

Usage is something like this (I'm not great with Javascript regex):

var match = HOSTDOMAIN.exec('www.google.co.in');
if (match == null) {
    alert('not a valid domain!');
} else {
    domain = match[0];
}