Question

I know I can grab the entire referring url by using:

document.referrer

But how would I only grab the base domain of the referrer?? So:

if(document.referrer === subdomain.domain.com){

}

So all referring urls coming from that main domain would work and all strings coming after the base domain are ignored.

Answer 1

At its simplest, just check document.referrer.indexOf("example.com") > -1. The downside of this is that if the referring page is http://somethingevil.com/pages/example.com then you’ll get a false match on the check.

You could go for a regex, something like: /^https?:\/\/example\.com\// as this will be more reliable of a check, but a harder one to cover edge cases like subdomains, ports, accessing via the IP address, etc..