location.host vs location.hostname and cross-browser compatibility?

location.host vs location.hostname and cross-browser compatibility?

Which one of these is the most effective vs checking if the user agent is accessing via the correct domain.
We would like to show a small js based ‘top bar’ style warning if they are accessing the domain using some sort of web proxy (as it tends to break the js).
We were thinking about using the following:
var r = /.*domain\.com$/;
if (r.test(location.hostname)) {
// showMessage …

That would take care of any subdomains we ever use.
Which should we use host or hostname?
In Firefox 5 and Chrome 12:

.. shows the same for both.
Is that because the port isn’t actually in the address bar?
W3Schools says host contains the port.
Should location.host/hostname be validated or can we be pretty certain in IE6+ and all the others it will exist?


Solution 1:

interactive link anatomy

As a little memo: the interactive link anatomy

In short (assuming a location of http://example.org:8888/foo/bar#bang):

  • hostname gives you example.org
  • host gives you example.org:8888

Solution 2:

host just includes the port number if there is one specified. If there is no port number specifically in the URL, then it returns the same as hostname. You pick whether you care to match the port number or not. See https://developer.mozilla.org/en/window.location for more info.

I would assume you want hostname to just get the site name.

Solution 3:

If you are insisting to use the window.location.origin
You can put this in top of your code before reading the origin

if (!window.location.origin) {
  window.location.origin = window.location.protocol + "//" + window.location.hostname + (window.location.port ? ':' + window.location.port: '');


PS: For the record, it was actually the original question. It was already edited 🙂

Solution 4:

Your primary question has been answered above. I just wanted to point out that the regex you’re using has a bug. It will also succeed on foo-domain.com which is not a subdomain of domain.com

What you really want is this:


Solution 5:

MDN: https://developer.mozilla.org/en/DOM/window.location

It seems that you will get the same result for both, but hostname contains clear host name without brackets or port number.

Solution 6:

Just to add a note that Google Chrome browser has origin attribute for the location. which gives you the entire domain from protocol to the port number as shown in the below screenshot.
chrome developers tool