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Simplest way to check if the current url contains a subdomain

I'm looking for the simplest way to check if the user is on the normal domain (domain.com) or is on a subdomain et.domain.com and display content based on that. If it matters I'm trying to do that on shopify.

You can split the url with dot(.) and check the length. This will only work for .com url.
Note: This will not work for domains like google.co.in
const domain = 'domain.com';
const subDomain = 'et.domain.com'
const isSubdomain = (domain) => domain.split('.').length > 2;
console.log(isSubdomain(domain));
console.log(isSubdomain(subDomain));

You can actually use regex method.
var isSubdomain = function(url) {
url = url || 'http://www.test-domain.com'; // just for the example
var regex = new RegExp(/^([a-z]+\:\/{2})?([\w-]+\.[\w-]+\.\w+)$/);
return !!url.match(regex); // make sure it returns boolean
}
console.log(isSubdomain("example.com"));
console.log(isSubdomain("http://example.com:4000"));
console.log(isSubdomain("www.example.com:4000"));
console.log(isSubdomain("https://www.example.com"));
console.log(isSubdomain("sub.example.com"));
console.log(isSubdomain("example.co.uk")); //it doesn't work on these very specific cases

Javascript: Compare top-level domain [duplicate]

How i can get the domain name example.com from the set of possible subdomains sub1.example.com sub2.example.com sub3.example.com using javascript ...?

var parts = location.hostname.split('.');
var subdomain = parts.shift();
var upperleveldomain = parts.join('.');
To get only the second-level-domain, you might use
var parts = location.hostname.split('.');
var sndleveldomain = parts.slice(-2).join('.');

The accepted answer will work to get the second level domain. However, there is something called "public suffixes" that you may want to take into account. Otherwise, you may get unexpected and erroneous results.
For example, take the domain www.amazon.co.uk.
If you just try getting the second level domain, you'll end up with co.uk, which is probably not what you want. That's because co.uk is a "public suffix", which means it's essentially a top level domain. Here's the definition of a public suffix, taken from https://publicsuffix.org:
A "public suffix" is one under which Internet users can (or historically could) directly register names.
If this is a crucial part of your application, I would look into something like psl (https://github.com/lupomontero/psl) for domain parsing. It works in nodejs and the browser, and it's tested on Mozilla's maintained public suffix list.
Here's a quick example from their README:
var psl = require('psl');
// TLD with some 2-level rules.
psl.get('uk.com'); // null);
psl.get('example.uk.com'); // 'example.uk.com');
psl.get('b.example.uk.com'); // 'example.uk.com');

This is faster
const firstDotIndex = subDomain.indexOf('.');
const domain = subDomain.substring(firstDotIndex + 1);

The generic solution is explained here http://rossscrivener.co.uk/blog/javascript-get-domain-exclude-subdomain
From above link
var domain = (function(){
var i=0,domain=document.domain,p=domain.split('.'),s='_gd'+(new Date()).getTime();
while(i<(p.length-1) && document.cookie.indexOf(s+'='+s)==-1){
domain = p.slice(-1-(++i)).join('.');
document.cookie = s+"="+s+";domain="+domain+";";
}
document.cookie = s+"=;expires=Thu, 01 Jan 1970 00:00:01 GMT;domain="+domain+";";
return domain;
})();

function getDomain() {
const hostnameArray = window.location.hostname.split('.')
const numberOfSubdomains = hostnameArray.length - 2
return hostnameArray.length === 2 ? window.location.hostname : hostnameArray.slice(numberOfSubdomains).join('.')
}
console.log(getDomain());
This will remove all subdomains, so "a.b.c.d.test.com" will become "test.com"

If you want to verify if a specific subdomain exists
var parts = location.hostname.split('.');
if(parts.includes('subdomain_to_search_here')){
//yes
}else{
//no
}

some more robust version, which is independent of the subdomain count
function getDomain() {
const hostname = window.location.hostname.split('.');
hostname.reverse();
return `${hostname[1]}.${hostname[0]}`;
}

Relative URLs for POSTS with Javascript/Jquery - concise

I have a c# MVC project with some jQuery driven interface. Some actions are performed with a $.post().
Sometimes, the site would be deployed to the root of the domain (e.g. www.mydomain.com) and sometimes it would be deployed in a folder (e.g. www.mydomain.com/Super).
I want to make posts to controllers relative to the location of the view that the user is accessing. However, the user may access the view both with and without an ending /, so i need to cater for both scenarios to avoid weird requests to www.mydomain.com/Super//somecontroller.
Currently, i have a function that does the following:
function getlocation() {
var loc = "";
if (location.pathname != "/") {
loc = (window.location.href.match("/$")) ? window.location.href : window.location.href + "/";
}
return loc;
}
Ultimately, this looks pretty ugly to me. Besides, every time i want to make a post or insert a relative URL when parsing data, i have to insert the result of that function before the actual URL which contributes to tag soup.
What is the best way to approach this?

I think your code is not ugly, but you can look to Backbone.js code:
url: function() {
var base = _.result(this, 'urlRoot') || _.result(this.collection, 'url') || urlError();
if (this.isNew()) return base;
return base + (base.charAt(base.length - 1) === '/' ? '' : '/') + encodeURIComponent(this.id);
},

This is a case of me not asking the question correctly.
The problem as i had it is best solved using Url.Action() method from the UrlHelper.

Get The Current Domain Name With Javascript (Not the path, etc.)

I plan on buying two domain names for the same site. Depending on which domain is used I plan on providing slightly different data on the page. Is there a way for me to detect the actual domain name that the page is loading from so that I know what to change my content to?
I've looked around for stuff like this but most of it doesn't work the way I want it to.
For instance when using
document.write(document.location)
on JSFiddle it returns
http://fiddle.jshell.net/_display/
i.e. the actual path or whatever that is.

How about:
window.location.hostname
The location object actually has a number of attributes referring to different parts of the URL

Let's suppose you have this url path:
http://localhost:4200/landing?query=1#2
So, you can serve yourself by the location values, as follow:
window.location.hash: "#2"
​
window.location.host: "localhost:4200"
​
window.location.hostname: "localhost"
​
window.location.href: "http://localhost:4200/landing?query=1#2"
​
window.location.origin: "http://localhost:4200"
​
window.location.pathname: "/landing"
​
window.location.port: "4200"
​
window.location.protocol: "http:"
window.location.search: "?query=1"
Now we can conclude you're looking for:
window.location.hostname

If you are not interested in the host name (for example www.beta.example.com) but in the domain name (for example example.com), this works for valid host names:
function getDomainName(hostName)
{
return hostName.substring(hostName.lastIndexOf(".", hostName.lastIndexOf(".") - 1) + 1);
}

function getDomain(url, subdomain) {
subdomain = subdomain || false;
url = url.replace(/(https?:\/\/)?(www.)?/i, '');
if (!subdomain) {
url = url.split('.');
url = url.slice(url.length - 2).join('.');
}
if (url.indexOf('/') !== -1) {
return url.split('/')[0];
}
return url;
}
Examples
getDomain('http://www.example.com'); // example.com
getDomain('www.example.com'); // example.com
getDomain('http://blog.example.com', true); // blog.example.com
getDomain(location.href); // ..
Previous version was getting full domain (including subdomain). Now it determines the right domain depending on preference. So that when a 2nd argument is provided as true it will include the subdomain, otherwise it returns only the 'main domain'

If you wish a full domain origin, you can use this:
document.location.origin
And if you wish to get only the domain, use can you just this:
document.location.hostname
But you have other options, take a look at the properties in:
document.location

You can get it from location object in Javascript easily:
For example URL of this page is:
http://www.stackoverflow.com/questions/11401897/get-the-current-domain-name-with-javascript-not-the-path-etc
Then we can get the exact domain with following properties of location object:
location.host = "www.stackoverflow.com"
location.protocol= "http:"
you can make the full domain with:
location.protocol + "//" + location.host
Which in this example returns http://www.stackoverflow.com
I addition of this we can get full URL and also the path with other properties of location object:
location.href= "http://www.stackoverflow.com/questions/11401897/get-the-current-domain-name-with-javascript-not-the-path-etc"
location.pathname= "questions/11401897/get-the-current-domain-name-with-javascript-not-the-path-etc"

window.location.hostname is a good start. But it includes sub-domains, which you probably want to remove. E.g. if the hostname is www.example.com, you probably want just the example.com bit.
There are, as ever, corner cases that make this fiddly, e.g. bbc.co.uk. The following regex works well for me:
let hostname = window.location.hostname;
// remove any subdomains, e.g. www.example.com -> example.com
let domain = hostname.match(/^(?:.*?\.)?([a-zA-Z0-9\-_]{3,}\.(?:\w{2,8}|\w{2,4}\.\w{2,4}))$/)[1];
console.log("domain: ", domain);

Since this question asks for domain name, not host name, a correct answer should be
window.location.hostname.split('.').slice(-2).join('.')
This works for host names like www.example.com too.

If you are only interested in the domain name and want to ignore the subdomain then you need to parse it out of host and hostname.
The following code does this:
var firstDot = window.location.hostname.indexOf('.');
var tld = ".net";
var isSubdomain = firstDot < window.location.hostname.indexOf(tld);
var domain;
if (isSubdomain) {
domain = window.location.hostname.substring(firstDot == -1 ? 0 : firstDot + 1);
}
else {
domain = window.location.hostname;
}
http://jsfiddle.net/5U366/4/

Use
document.write(document.location.hostname)​
window.location has a bunch of properties. See here for a list of them.

I figure it ought to be as simple as this:
url.split("/")[2]

If you want to get domain name in JavaScript, just use the following code:
var domain_name = document.location.hostname;
alert(domain_name);
If you need to web page URL path so you can access web URL path use this example:
var url = document.URL;
alert(url);

What about this function?
window.location.hostname.match(/\w*\.\w*$/gi)[0]
This will match only the domain name regardless if its a subdomain or a main domain

for my case the best match is window.location.origin

Combining a few answers from the above, the following works really well for me for destroying Cookies:
/**
* Utility method to obtain the domain URI:
*/
fetchDomainURI() {
if (window.location.port.length > 0) {
return window.location.hostname;
}
return `.${window.location.hostname.match(/\w*\.\w*$/gi)[0]}`;
}
Works for IP addresses with ports, e.g., 0.0.0.0:8000 etc, as well as complex domains like app.staging.example.com returning .example.com => allows for cross-domain Cookie setting and destroying.

I'm new to JavaScript, but cant you just use: document.domain ?
Example:
<p id="ourdomain"></p>
<script>
var domainstring = document.domain;
document.getElementById("ourdomain").innerHTML = (domainstring);
</script>
Output:
domain.com
or
www.domain.com
Depending on what you use on your website.

Even if the question is about the domain name, the accepted solution includes the subdomain (eg. you get blog.example.com calling location.hostname).
For future reference I suggest a one-liner to extract only the domain (eg. https://blog.example.com/index.html -> example.com) as Micheal.
location.hostname.split('.').filter(( _, i) => i < 2).join('.')
Beware! It can break when the TLD is composed of two parts (eg. .co.uk). If that's your case change 2 with 3 in the code above.

you can use this to do away with the port number.
var hostname = window.location.host;
var urlWithoutPort = `https://${hostname}`;
console.log(urlWithoutPort);

https://publicsuffix.org/list/
(https://github.com/publicsuffix/list/blob/master/public_suffix_list.dat)
is needed to correctly parse out all domains without suffixes, working with dots as in the answers above will never completely be correct. Feel free to run the above codes samples against the public suffixes dat file to realize this.
You can roll your own code based on this or use a package like https://www.npmjs.com/package/tldts
getDomainWithoutSuffix('google.com'); // returns `google`
getDomainWithoutSuffix('fr.google.com'); // returns `google`
getDomainWithoutSuffix('fr.google.google'); // returns `google`
getDomainWithoutSuffix('foo.google.co.uk'); // returns `google`
getDomainWithoutSuffix('t.co'); // returns `t`
getDomainWithoutSuffix('fr.t.co'); // returns `t`
getDomainWithoutSuffix('https://user:password#example.co.uk:8080/some/path?and&query#hash'); // returns `example`

If excludes url containing www

I have the below JavaScript, and when the url (window.location) does not contain www. the javascript IS executed
var windowloc = window.location; // http://mywebsite.com/
var homeurl = "http://mywebsite.com/";
if(windowloc==homeurl){
//JavaScript IS EXECUTED
}
and if it does the javascript is not executed.
var windowloc = window.location; // http://www.mywebsite.com/
var homeurl = "http://mywebsite.com/";
if(windowloc==homeurl){
//JavaScript is NOT executed.
}
How can I overcome this by allowing the JavaScript to accept urls (window.location) with and without www.

Use code like this see if the domain has www.mywebsite.com in it:
if (window.location.href.indexOf("//www.mywebsite.com/") != -1) {
// code to execute if it is www.mywebsite.com
} else {
// code to execute if it is not www.mywebsite.com
}
or, you could use just the hostname part of window.location like this to just check for the "www.":
if (window.location.hostname.indexOf("www.") != -1) {
// code to execute if it is www. something
} else {
// code to execute if it is not www. something
}
or if you wanted to check for exactly your entire domain, you could do it like this:
if (window.location.hostname === "www.mywebsite.com" {
// code to execute if it is www.mywebsite.com
} else {
// code to execute if it is not www.mywebsite.com
}

You can overcome that using regex, as I am sure other answers will provide. However, it's best practice for search engine optimization (SEO) to force your http://mywebsite.com/ to do a perminant redirect to http://www.mywebsite.com/ because search engines like Google consider the www. and www-less versions two separate websites.
Then you will not need two separate conditions because your url will always be the www. version.

if (window.location.href.indexOf("://www") === -1) {
// "www" excluded
} else {
// other stuff
}
edited the code sample to be more specific

if(window.location.href.indexOf('mywebsite.com')!= -1){
//do stuff
}

Use the hostname property of the location object to determine what address you're being served under:
if (location.hostname==='mywebsite.com')
// do something
location and other address-owning objects like links have properties like hostname, pathname, search and hash to give you the already-parsed pieces of the URL, so you don't have to try to pick apart URL strings yourself. Don't just look for the presence of www. in the location string as it might be somewhere else in the string that isn't the hostname.
But +1 Justin's answer: if you are trying to redirect alternative addresses such as a non-www address to a canonical address, the right way to do that is with an HTTP 301 redirect and not anything to do with JavaScript. This would normally be configured at the server level, eg for Apache you might use a Redirect in your .htaccess.