How do I get the referrer's domain/host name using JavaScript?

I know I can get the host name of the current page, by simply doing:

var myhostname = location.hostname;

But how do I get the host name of the referrer? I can get the referrer by

var referrer = document.referrer;

but unfortunately there's no document.referrer.hostname available in JavaScript. How can I get this value?

An example of where this is useful is if somebody clicks a link on google.com. I want to be able to retrieve google.com from the referrer (not the page and the query string).

This would do:

document.referrer.split('/')[2];

Example.

function parseURL(url) {
    var a=document.createElement('a');
    a.href=url;
    return a.hostname;
}

This is a relatively old question, nevertheless this may help any followers.

By parsing it. document.referrer.split( '/' ); will get you close. Or take a look at this

http://blog.stevenlevithan.com/archives/parseuri

If referrer is coming from a browser, it will be sane -- but just in case you want more robust parsing.

You can use var referrer = new URL(document.referrer).hostname.

See https://developer.mozilla.org/en-US/docs/Web/API/URL.URL.

You can use regexp to extract this data.

string.match(/^http([s]?)://([a-zA-Z0-9-_\.]+)(:[0-9]+)?/);