Get domain name without subdomains using JavaScript?

Question

How to get the domain name without subdomains?

e.g. if the url is "http://one.two.roothost.co.uk/page.html" how to get "roothost.co.uk"?

Answer 1

Following is a solution to extract a domain name without any subdomains. This solution doesn't make any assumptions about the URL format, so it should work for any URL. Since some domain names have one suffix (.com), and some have two or more (.co.uk), to get an accurate result in all cases, we need to parse the hostname using the Public Suffix List, which contains a list of all public domain name suffixes.

---

Solution

First, include the public suffix list js api in a script tag in your HTML, then in JavaScript to get the hostname you can call:

var parsed = psl.parse('one.two.roothost.co.uk');
console.log(parsed.domain);

...which will return "roothost.co.uk". To get the name from the current page, you can use location.hostname instead of a static string:

var parsed = psl.parse(location.hostname);
console.log(parsed.domain);

Finally, if you need to parse a domain name directly out of a full URL string, you can use the following:

var url = "http://one.two.roothost.co.uk/page.html";
url = url.split("/")[2]; // Get the hostname
var parsed = psl.parse(url); // Parse the domain
document.getElementById("output").textContent = parsed.domain;

JSFiddle Example (it includes the entire minified library in the jsFiddle, so scroll down!): https://jsfiddle.net/6aqdbL71/2/

Answer 2

This works for me:

const firstTLDs = "ac|ad|ae|af|ag|ai|al|am|an|ao|aq|ar|as|at|au|aw|ax|az|ba|bb|be|bf|bg|bh|bi|bj|bm|bo|br|bs|bt|bv|bw|by|bz|ca|cc|cd|cf|cg|ch|ci|cl|cm|cn|co|cr|cu|cv|cw|cx|cz|de|dj|dk|dm|do|dz|ec|ee|eg|es|et|eu|fi|fm|fo|fr|ga|gb|gd|ge|gf|gg|gh|gi|gl|gm|gn|gp|gq|gr|gs|gt|gw|gy|hk|hm|hn|hr|ht|hu|id|ie|il|im|in|io|iq|ir|is|it|je|jo|jp|kg|ki|km|kn|kp|kr|ky|kz|la|lb|lc|li|lk|lr|ls|lt|lu|lv|ly|ma|mc|md|me|mg|mh|mk|ml|mn|mo|mp|mq|mr|ms|mt|mu|mv|mw|mx|my|na|nc|ne|nf|ng|nl|no|nr|nu|nz|om|pa|pe|pf|ph|pk|pl|pm|pn|pr|ps|pt|pw|py|qa|re|ro|rs|ru|rw|sa|sb|sc|sd|se|sg|sh|si|sj|sk|sl|sm|sn|so|sr|st|su|sv|sx|sy|sz|tc|td|tf|tg|th|tj|tk|tl|tm|tn|to|tp|tr|tt|tv|tw|tz|ua|ug|uk|us|uy|uz|va|vc|ve|vg|vi|vn|vu|wf|ws|yt".split('|');

const secondTLDs = "com|edu|gov|net|mil|org|nom|sch|caa|res|off|gob|int|tur|ip6|uri|urn|asn|act|nsw|qld|tas|vic|pro|biz|adm|adv|agr|arq|art|ato|bio|bmd|cim|cng|cnt|ecn|eco|emp|eng|esp|etc|eti|far|fnd|fot|fst|g12|ggf|imb|ind|inf|jor|jus|leg|lel|mat|med|mus|not|ntr|odo|ppg|psc|psi|qsl|rec|slg|srv|teo|tmp|trd|vet|zlg|web|ltd|sld|pol|fin|k12|lib|pri|aip|fie|eun|sci|prd|cci|pvt|mod|idv|rel|sex|gen|nic|abr|bas|cal|cam|emr|fvg|laz|lig|lom|mar|mol|pmn|pug|sar|sic|taa|tos|umb|vao|vda|ven|mie|北海道|和歌山|神奈川|鹿児島|ass|rep|tra|per|ngo|soc|grp|plc|its|air|and|bus|can|ddr|jfk|mad|nrw|nyc|ski|spy|tcm|ulm|usa|war|fhs|vgs|dep|eid|fet|fla|flå|gol|hof|hol|sel|vik|cri|iwi|ing|abo|fam|gok|gon|gop|gos|aid|atm|gsm|sos|elk|waw|est|aca|bar|cpa|jur|law|sec|plo|www|bir|cbg|jar|khv|msk|nov|nsk|ptz|rnd|spb|stv|tom|tsk|udm|vrn|cmw|kms|nkz|snz|pub|fhv|red|ens|nat|rns|rnu|bbs|tel|bel|kep|nhs|dni|fed|isa|nsn|gub|e12|tec|орг|обр|упр|alt|nis|jpn|mex|ath|iki|nid|gda|inc".split('|');

const knownSubdomains = "www|studio|mail|remote|blog|webmail|server|ns1|ns2|smtp|secure|vpn|m|shop|ftp|mail2|test|portal|ns|ww1|host|support|dev|web|bbs|ww42|squatter|mx|email|1|mail1|2|forum|owa|www2|gw|admin|store|mx1|cdn|api|exchange|app|gov|2tty|vps|govyty|hgfgdf|news|1rer|lkjkui";

function removeSubdomain(s) {
    const knownSubdomainsRegExp = new RegExp(`^(${knownSubdomains})\.`, 'i');
    s = s.replace(knownSubdomainsRegExp, '');

    const parts = s.split('.');

    while (parts.length > 3) {
        parts.shift();
    }

    if (parts.length === 3 && ((parts[1].length > 2 && parts[2].length > 2) || (secondTLDs.indexOf(parts[1]) === -1) && firstTLDs.indexOf(parts[2]) === -1)) {
        parts.shift();
    }

    return parts.join('.');
};

var tests = {
  'www.sidanmor.com':             'sidanmor.com',
  'exemple.com':                  'exemple.com',
  'argos.co.uk':                  'argos.co.uk',
  'www.civilwar.museum':          'civilwar.museum',
  'www.sub.civilwar.museum':      'civilwar.museum',
  'www.xxx.sub.civilwar.museum':  'civilwar.museum',
  'www.exemple.com':              'exemple.com',
  'main.testsite.com':            'testsite.com',
  'www.ex-emple.com.ar':          'ex-emple.com.ar',
  'main.test-site.co.uk':         'test-site.co.uk',
  'en.tour.mysite.nl':            'tour.mysite.nl',
  'www.one.lv':                   'one.lv',
  'www.onfdsadfsafde.lv':         'onfdsadfsafde.lv',
  'aaa.onfdsadfsafde.aa':         'onfdsadfsafde.aa',
};

const firstTLDs = "ac|ad|ae|af|ag|ai|al|am|an|ao|aq|ar|as|at|au|aw|ax|az|ba|bb|be|bf|bg|bh|bi|bj|bm|bo|br|bs|bt|bv|bw|by|bz|ca|cc|cd|cf|cg|ch|ci|cl|cm|cn|co|cr|cu|cv|cw|cx|cz|de|dj|dk|dm|do|dz|ec|ee|eg|es|et|eu|fi|fm|fo|fr|ga|gb|gd|ge|gf|gg|gh|gi|gl|gm|gn|gp|gq|gr|gs|gt|gw|gy|hk|hm|hn|hr|ht|hu|id|ie|il|im|in|io|iq|ir|is|it|je|jo|jp|kg|ki|km|kn|kp|kr|ky|kz|la|lb|lc|li|lk|lr|ls|lt|lu|lv|ly|ma|mc|md|me|mg|mh|mk|ml|mn|mo|mp|mq|mr|ms|mt|mu|mv|mw|mx|my|na|nc|ne|nf|ng|nl|no|nr|nu|nz|om|pa|pe|pf|ph|pk|pl|pm|pn|pr|ps|pt|pw|py|qa|re|ro|rs|ru|rw|sa|sb|sc|sd|se|sg|sh|si|sj|sk|sl|sm|sn|so|sr|st|su|sv|sx|sy|sz|tc|td|tf|tg|th|tj|tk|tl|tm|tn|to|tp|tr|tt|tv|tw|tz|ua|ug|uk|us|uy|uz|va|vc|ve|vg|vi|vn|vu|wf|ws|yt".split('|');

const secondTLDs = "com|edu|gov|net|mil|org|nom|sch|caa|res|off|gob|int|tur|ip6|uri|urn|asn|act|nsw|qld|tas|vic|pro|biz|adm|adv|agr|arq|art|ato|bio|bmd|cim|cng|cnt|ecn|eco|emp|eng|esp|etc|eti|far|fnd|fot|fst|g12|ggf|imb|ind|inf|jor|jus|leg|lel|mat|med|mus|not|ntr|odo|ppg|psc|psi|qsl|rec|slg|srv|teo|tmp|trd|vet|zlg|web|ltd|sld|pol|fin|k12|lib|pri|aip|fie|eun|sci|prd|cci|pvt|mod|idv|rel|sex|gen|nic|abr|bas|cal|cam|emr|fvg|laz|lig|lom|mar|mol|pmn|pug|sar|sic|taa|tos|umb|vao|vda|ven|mie|北海道|和歌山|神奈川|鹿児島|ass|rep|tra|per|ngo|soc|grp|plc|its|air|and|bus|can|ddr|jfk|mad|nrw|nyc|ski|spy|tcm|ulm|usa|war|fhs|vgs|dep|eid|fet|fla|flå|gol|hof|hol|sel|vik|cri|iwi|ing|abo|fam|gok|gon|gop|gos|aid|atm|gsm|sos|elk|waw|est|aca|bar|cpa|jur|law|sec|plo|www|bir|cbg|jar|khv|msk|nov|nsk|ptz|rnd|spb|stv|tom|tsk|udm|vrn|cmw|kms|nkz|snz|pub|fhv|red|ens|nat|rns|rnu|bbs|tel|bel|kep|nhs|dni|fed|isa|nsn|gub|e12|tec|орг|обр|упр|alt|nis|jpn|mex|ath|iki|nid|gda|inc".split('|');

const knownSubdomains = "www|studio|mail|remote|blog|webmail|server|ns1|ns2|smtp|secure|vpn|m|shop|ftp|mail2|test|portal|ns|ww1|host|support|dev|web|bbs|ww42|squatter|mx|email|1|mail1|2|forum|owa|www2|gw|admin|store|mx1|cdn|api|exchange|app|gov|2tty|vps|govyty|hgfgdf|news|1rer|lkjkui";

function removeSubdomain(s) {
const knownSubdomainsRegExp = new RegExp(`^(${knownSubdomains})\.`, 'i');
s = s.replace(knownSubdomainsRegExp, '');

const parts = s.split('.');

while (parts.length > 3) {
    parts.shift();
}

if (parts.length === 3 && ((parts[1].length > 2 && parts[2].length > 2) || (secondTLDs.indexOf(parts[1]) === -1) && firstTLDs.indexOf(parts[2]) === -1)) {
    parts.shift();
}

return parts.join('.');
};

for (var test in tests) {
  if (tests.hasOwnProperty(test)) {
    var t = test;
    var e = tests[test];
    var r = removeSubdomain(test);
    var s = e === r;
    if (s) {
      console.log('OK: "' + t + '" should be "' + e + '" and it is really "' + r + '"');
    } else {
      console.log('Fail: "' + t + '" should be "' + e + '" but it is NOT "' + r + '"');
    }
  }
}

Referance:

psl.min.js file

Maximillian Laumeister Answer to this question

The most popular subdomains on the internet

Answer 3

You can use parse-domain to do the heavy lifting for you. This package considers the public suffix list and returns an easy to work with object breaking up the domain.

Here is an example from their readme:

  npm install parse-domain

  import { parseDomain, ParseResultType } from 'parse-domain';

  const parseResult = parseDomain(
    // should be a string with basic latin characters only. more details in the readme
    'www.some.example.co.uk',
  );

  // check if the domain is listed in the public suffix list
  if (parseResult.type === ParseResultType.Listed) {
    const { subDomains, domain, topLevelDomains } = parseResult;

    console.log(subDomains); // ["www", "some"]
    console.log(domain); // "example"
    console.log(topLevelDomains); // ["co", "uk"]
  } else {
    // more about other parseResult types in the readme
  }

Answer 4

What about this?

function getCanonicalHost(hostname) {
  const MAX_TLD_LENGTH = 3;
  
  function isNotTLD(_) { return _.length > MAX_TLD_LENGTH; };

  hostname = hostname.split('.');
  hostname = hostname.slice(Math.max(0, hostname.findLastIndex(isNotTLD)));
  hostname = hostname.join('.');

  return hostname;
}

console.log(getCanonicalHost('mail.google.com'));
console.log(getCanonicalHost('some.google.com.ar'));
console.log(getCanonicalHost('some.another.google.com.ar'));
console.log(getCanonicalHost('foo.bar.google.com'));
console.log(getCanonicalHost('foo.bar.google.com.ar'));
console.log(getCanonicalHost('bar.google.ar'));

Its works since https://developer.mozilla.org/en-US/docs/Learn/Common_questions/What_is_a_domain_name say:

TLDs can contain special as well as latin characters. A TLD's maximum length is 63 characters, although most are around 2–3.

In https://data.iana.org/TLD/tlds-alpha-by-domain.txt are 1481 TLD, 466 of this has length around 2–3 and the most used TLD no has more than 3.

If you need a solution that works with all TLDS, here is a more complex aproach:

function getCanonicalHost(hostname) {
  return getCanonicalHost.tlds.then(function(tlds) {   
    function isNotTLD(_) { return tlds.indexOf(_) === -1; };

    hostname = hostname.toLowerCase();
    hostname = hostname.split('.');
    hostname = hostname.slice(Math.max(0, hostname.findLastIndex(isNotTLD)));
    hostname = hostname.join('.');

    return hostname; 
  });
}

getCanonicalHost.tlds = new Promise(function(res, rej) {
  const TLD_LIST_URL= 'https://data.iana.org/TLD/tlds-alpha-by-domain.txt';

  const xhr = new XMLHttpRequest();

  xhr.addEventListener('error', rej);
  xhr.addEventListener('load', function() { 
    const MAX_TLD_LENGTH = 63;

    var tlds = xhr.responseText.split('\n');
    tlds = tlds.map(function(_) { return _.trim().toLowerCase(); });
    tlds = tlds.filter(Boolean);
    tlds = tlds.filter(function(_) { return _.length < MAX_TLD_LENGTH; });

    res(tlds);
  });

  xhr.open('GET', TLD_LIST_URL);
  xhr.send();
})

getCanonicalHost('mail.google.com').then(console.log);
getCanonicalHost('some.google.com.ar').then(console.log);
getCanonicalHost('some.another.google.com.ar').then(console.log);
getCanonicalHost('foo.bar.google.com').then(console.log);
getCanonicalHost('foo.bar.google.com.ar').then(console.log);
getCanonicalHost('bar.google.ar').then(console.log);

Answer 5

Just use the code snippet below.

/(?<=\.).+/.exec(location.hostname)[0]

Answer 6

Simplest solution:

var domain='https://'+window.location.hostname.split('.')[window.location.hostname.split('.').length-2]+'.'+window.location.hostname.split('.')[window.location.hostname.split('.').length-1];
alert(domain);

Answer 7

I created this function which uses URL to parse. It cheats by assuming all hostnames will have either 4 or less parts.

const getDomainWithoutSubdomain = url => {
  const urlParts = new URL(url).hostname.split('.')

  return urlParts
    .slice(0)
    .slice(-(urlParts.length === 4 ? 3 : 2))
    .join('.')
}

[
  'https://www.google.com',
  'https://www.google.co.uk',
  'https://mail.google.com',
  'https://www.bbc.co.uk/news',
  'https://github.com',
].forEach(url => {
  console.log(getDomainWithoutSubdomain(url))
})

Answer 8

Here is a working JSFiddle

My solution works with the assumption that the root hostname you are looking for is of the type "abc.xyz.pp".

extractDomain() returns the hostname with all the subdomains. getRootHostName() splits the hostname by . and then based on the assumption mentioned above, it uses the shift() to remove each subdomain name. Finally, whatever remains in parts[], it joins them by . to form the root hostname.

Javascript

var urlInput = "http://one.two.roothost.co.uk/page.html";

function extractDomain(url) {
    var domain;
    //find & remove protocol (http, ftp, etc.) and get domain
    if (url.indexOf("://") > -1) {
        domain = url.split('/')[2];
    } else {
        domain = url.split('/')[0];
    }

    //find & remove port number
    domain = domain.split(':')[0];

    return domain;
}

function getRootHostName(url) {
    var parts = extractDomain(url).split('.');
    var partsLength = parts.length - 3;

    //parts.length-3 assuming root hostname is of type abc.xyz.pp
    for (i = 0; i < partsLength; i++) {
        parts.shift(); //remove sub-domains one by one
    }
    var rootDomain = parts.join('.');

    return rootDomain;
}

document.getElementById("result").innerHTML = getRootHostName(urlInput);

HTML

<div id="result"></div>

EDIT 1: Updated the JSFiddle link. It was reflecting the incorrect code.

Answer 9

What about...

    function getDomain(){
        if(document.domain.length){
            var parts = document.domain.replace(/^(www\.)/,"").split('.');

            //is there a subdomain? 
            while(parts.length > 2){
                //removing it from our array 
                var subdomain = parts.shift();
            }

            //getting the remaining 2 elements
            var domain = parts.join('.');

            return domain.replace(/(^\.*)|(\.*$)/g, "");
        }
        return '';
    }

Answer 10

My solution worked for me: Get "gocustom.com" from "shop.gocustom.com"

var site_domain_name = 'shop.gocustom.com';
alert(site_domain_name);
var strsArray = site_domain_name.split('.');
var strsArrayLen = strsArray.length;
alert(strsArray[eval(strsArrayLen - 2)]+'.'+strsArray[eval(strsArrayLen - 1)])

Answer 11

You can try this in JavaScript:

alert(window.location.hostname);

It will return the hostname.