Determine domain name in JavaScript?

Question

What's the difference between using

if (document.domain.toLowerCase().indexOf("domainName") != -1)

and

if(window.location.href.match(/:\/\/(.[^/]+)/)[1].toLowerCase().indexOf("domainName") != -1)

and

if(window.location.hostname.toLowerCase().indexOf("domainName") != -1)

I'm just trying to match on a certain domainName and want to use the best approach.

Answer 1

Best and most readable would be:

if(location.hostname == "mysite.com"){

}

---

Update:

Or as Patrick pointed out if you are only looking for part of the domain name I would use match.

if(location.hostname.match('mysite')){} // will return null if no match is found

Answer 2

Readable Method:

You can use endsWith() to compare the end of the hostname string with the domain name:

location.hostname === 'stackexchange.com' || location.hostname.endsWith('.stackexchange.com')

Note: This requires ECMAScript 6 (ES6) support.

Short Method:

Or if you would prefer to use a regex with the test() method, you can use:

/(^|\.)stackexchange\.com$/.test(location.hostname)

Split/Join Array-to-String Method:

Additionally, you can also split() the hostname into an array based on the . character. Then you can take the last two elements (the domain name and extension) using slice(), and join() them back together with the . character as the separator, which will allow you to compare directly to the expected domain name:

location.hostname.split('.').slice(-2).join('.') === 'stackexchange.com'

This will return true for the following types of URLs:

• https://stackexchange.com/
• https://stackexchange.com/tour
• https://dba.stackexchange.com/
• https://dba.stackexchange.com/tour