如何从 JavaScript 中的 URL 获取基本域

How to get base domain from the URL in JavaScript

提问by anishenos

I would like to extract the base domain from the url in javascript. For example for the list of urls listed below I need to get google.com(or google.co.inas the case may be) as the result.

我想从 javascript 中的 url 中提取基本域。例如，对于下面列出的网址列表，我需要获取google.com（或google.co.in，视情况而定）作为结果。

www.google.com
www.google.co.in
www.images.google.com
www.images.google.co.in
google.com
google.co.in
images.google.com
images.google.co.in

www.google.com
www.google.co.in
www.images.google.com
www.images.google.co.in
google.com
google.co.in
images.google.com
images.google.co.in

Any one got some idea on how to do it. There is no direct method to find the base url in javascript i guess.

任何人都知道如何做到这一点。我猜没有直接的方法可以在 javascript 中找到基本 url。

回答by Eduardo

This one works only if you are at the url you want to get the TLD.

仅当您位于要获取 TLD 的网址时，此方法才有效。

This function guarantees you get the top-level hostname because that's the one a browser allows you to store cookies. So we basically test if for a given prefix we are able to set cookies, if so we return that otherwise we try the next prefix until we find the one the browser allows cookies in.

此函数可确保您获得顶级主机名，因为这是浏览器允许您存储 cookie 的主机名。所以我们基本上测试我们是否能够为给定的前缀设置 cookie，如果是，我们返回，否则我们尝试下一个前缀，直到我们找到浏览器允许 cookie 的那个。

Will fail if the browser is configured to disallow cookies, or possibly in restricted hostnames such as localhost

如果浏览器被配置为禁止 cookie，或者可能在受限制的主机名中，例如 localhost

function get_top_domain(){
  var i,h,
    weird_cookie='weird_get_top_level_domain=cookie',
    hostname = document.location.hostname.split('.');
  for(i=hostname.length-1; i>=0; i--) {
    h = hostname.slice(i).join('.');
    document.cookie = weird_cookie + ';domain=.' + h + ';';
    if(document.cookie.indexOf(weird_cookie)>-1){
      // We were able to store a cookie! This must be it
      document.cookie = weird_cookie.split('=')[0] + '=;domain=.' + h + ';expires=Thu, 01 Jan 1970 00:00:01 GMT;';
      return h;
    }
  }
}

回答by Simon Buchan

This depends on just how rigorous you need to be. The full list of valid top-level domains is given here, but the rules given hereare possibly more helpful.

这取决于您需要多严格。有效的顶级域的完整列表给出了这里，但给出的规则在这里都可能更有帮助。

A simple, probably incomplete regex:

一个简单的，可能不完整的正则表达式：

/[-\w]+\.(?:[-\w]+\.xn--[-\w]+|[-\w]{3,}|[-\w]+\.[-\w]{2})$/i

Usage is something like this (I'm not great with Javascript regex):

用法是这样的（我不擅长 Javascript 正则表达式）：

var match = HOSTDOMAIN.exec('www.google.co.in');
if (match == null) {
    alert('not a valid domain!');
} else {
    domain = match[0];
}

回答by lingeshram

You can try this method

你可以试试这个方法

var url = 'https://www.petzlover.com/us/search?pet=1&breed=262';

var url = ' https://www.petzlover.com/us/search?pet=1&breed=262';

extractHostname(url,true); //petzlover.com

提取主机名（网址，真）；//petzlover.com

extractHostname(url); //www.petzlover.com

提取主机名（网址）；//www.petzlover.com

function extractHostname(url,tld) {
      let hostname;

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

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

      //find & remove "?"
      hostname = hostname.split('?')[0];

      if(tld){
        let hostnames = hostname.split('.');
        hostname = hostnames[hostnames.length-2] + '.' + hostnames[hostnames.length-1];
      }

      return hostname;
  }

let url = 'https://www.petzlover.com/us/search?pet=1&breed=262';

let longUrl = 'https://www.fr.petzlover.com/us/search?pet=1&breed=262';

let topLevelDomain = extractHostname(url,true); //petzlover.com
let subDomain = extractHostname(url); //www.petzlover.com
let lengthySubDomain = extractHostname(longUrl); //www.fr.petzlover.com

document.getElementById('top-level-domain').innerHTML = topLevelDomain;
document.getElementById('sub-domain').innerHTML = subDomain;
document.getElementById('lengthy-sub-domain').innerHTML = lengthySubDomain;

    function extractHostname(url,tld) {
          let hostname;
    
          //find & remove protocol (http, ftp, etc.) and get hostname
          if (url.indexOf("://") > -1) {
              hostname = url.split('/')[2];
          }else {
              hostname = url.split('/')[0];
          }
    
          //find & remove port number
          hostname = hostname.split(':')[0];

          //find & remove "?"
          hostname = hostname.split('?')[0];
    
          if(tld){
            let hostnames = hostname.split('.');
            hostname = hostnames[hostnames.length-2] + '.' + hostnames[hostnames.length-1];
          }
    
          return hostname;
      }

span{
  font-weight:bold;
  font-size:16px;
}

<div>Top Level Domain: <span id="top-level-domain"></span> </div>
<div>Including sub Domain: <span id="sub-domain"></span> </div>
<div>Including lengthy sub Domain: <span id="lengthy-sub-domain"></span> </div>

回答by Mauricio Gracia Gutierrez

This is quite long but you can use the function extractRootDomainand the sintax is typescript

这很长，但您可以使用该函数extractRootDomain，并且语法是打字稿

extractHostname(url: stringType) {
let hostname: string;

// find & remove protocol (http, ftp, etc.) and get hostname

if (url.indexOf("//") > -1) {
  hostname = url.split("/")[2];
} else {
  hostname = url.split("/")[0];
}

// find & remove port number
hostname = hostname.split(":")[0];
// find & remove "?"
hostname = hostname.split("?")[0];

return hostname;
}

// To address those who want the "root domain," use this function:
extractRootDomain(url: string) {
let domain = this.extractHostname(url);
const splitArr = domain.split(".");
const arrLen = splitArr.length;

// extracting the root domain here
// if there is a subdomain
if (arrLen > 2) {
  domain = splitArr[arrLen - 2] + "." + splitArr[arrLen - 1];
  // check to see if it's using a Country Code Top Level Domain (ccTLD) (i.e. ".me.uk")
  if (
    (splitArr[arrLen - 2].length === 2 &&
    splitArr[arrLen - 1].length === 2)
    || this.isTopLevelDomain(domain)
  ) {
    // this is using a ccTLD
    domain = splitArr[arrLen - 3] + "." + domain;
  }
}
return domain;
}

isTopLevelDomain(url: string) {
const tld = [
  "edu.ac",
  "c.se",
  "d.se",
  "e.se",
  "f.se",
  "g.se",
  "h.se",
  "i.se",
  "k.se",
  "m.se",
  "n.se",
  "o.se",
  "s.se",
  "t.se",
  "u.se",
  "w.se",
  "x.se",
  "y.se",
  "z.se",
  "ac.ae",
  "co.ag",
  "co.ao",
  "ed.ao",
  "gv.ao",
  "it.ao",
  "og.ao",
  "pb.ao",
  "gv.at",
  "ac.at",
  "co.at",
  "or.at",
  "id.au",
  "oz.au",
  "nt.au",
  "sa.au",
  "wa.au",
  "pp.az",
  "ac.be",
  "tv.bo",
  "am.br",
  "fm.br",
  "tv.br",
  "co.bw",
  "ab.ca",
  "bc.ca",
  "mb.ca",
  "nb.ca",
  "nf.ca",
  "nl.ca",
  "ns.ca",
  "nt.ca",
  "nu.ca",
  "on.ca",
  "pe.ca",
  "qc.ca",
  "sk.ca",
  "yk.ca",
  "co.cc",
  "co.ck",
  "ac.cn",
  "ah.cn",
  "bj.cn",
  "cq.cn",
  "fj.cn",
  "gd.cn",
  "gs.cn",
  "gz.cn",
  "gx.cn",
  "ha.cn",
  "hb.cn",
  "he.cn",
  "hi.cn",
  "hl.cn",
  "hn.cn",
  "jl.cn",
  "js.cn",
  "jx.cn",
  "ln.cn",
  "nm.cn",
  "nx.cn",
  "qh.cn",
  "sc.cn",
  "sd.cn",
  "sh.cn",
  "sn.cn",
  "sx.cn",
  "tj.cn",
  "xj.cn",
  "xz.cn",
  "yn.cn",
  "zj.cn",
  "us.com",
  "ac.cr",
  "co.cr",
  "ed.cr",
  "fi.cr",
  "go.cr",
  "or.cr",
  "sa.cr",
  "tm.cy",
  "ac.cy",
  "ac.fj",
  "co.fk",
  "ac.fk",
  "tm.fr",
  "co.gg",
  "ac.gn",
  "iz.hr",
  "co.hu",
  "tm.hu",
  "ac.id",
  "co.id",
  "or.id",
  "go.id",
  "ac.il",
  "co.il",
  "co.im",
  "ac.im",
  "co.in",
  "ac.in",
  "ac.ir",
  "co.ir",
  "co.je",
  "ac.jp",
  "ad.jp",
  "co.jp",
  "ed.jp",
  "go.jp",
  "gr.jp",
  "lg.jp",
  "ne.jp",
  "or.jp",
  "co.kr",
  "or.kr",
  "co.ls",
  "id.lv",
  "id.ly",
  "co.ma",
  "tm.mc",
  "tm.mg",
  "co.mu",
  "ac.mw",
  "co.mw",
  "ac.nz",
  "co.nz",
  "co.om",
  "ac.com",
  "ac.pa",
  "tm.ro",
  "nt.ro",
  "pp.ru",
  "ac.ru",
  "ac.rw",
  "co.rw",
  "tv.sd",
  "pp.se",
  "tm.se",
  "fh.se",
  "ab.se",
  "ac.se",
  "bd.se",
  "ac.th",
  "co.th",
  "in.th",
  "go.th",
  "mi.th",
  "or.th",
  "ac.tj",
  "co.tj",
  "go.tj",
  "av.tr",
  "dr.tr",
  "co.tt",
  "co.tz",
  "ac.tz",
  "go.tz",
  "or.tz",
  "ne.tz",
  "ck.ua",
  "cn.ua",
  "cv.ua",
  "dp.ua",
  "dn.ua",
  "if.ua",
  "kh.ua",
  "ks.ua",
  "km.ua",
  "kv.ua",
  "kr.ua",
  "lg.ua",
  "mk.ua",
  "od.ua",
  "pl.ua",
  "rv.ua",
  "te.ua",
  "vn.ua",
  "zp.ua",
  "zt.ua",
  "co.ug",
  "ac.ug",
  "sc.ug",
  "go.ug",
  "ne.ug",
  "or.ug",
  "ac.uk",
  "co.uk",
  "me.uk",
  "bl.uk",
  "ak.us",
  "al.us",
  "ar.us",
  "az.us",
  "ca.us",
  "co.us",
  "ct.us",
  "dc.us",
  "de.us",
  "fl.us",
  "ga.us",
  "hi.us",
  "ia.us",
  "id.us",
  "il.us",
  "in.us",
  "ks.us",
  "ky.us",
  "la.us",
  "ma.us",
  "md.us",
  "me.us",
  "mi.us",
  "mn.us",
  "mo.us",
  "ms.us",
  "mt.us",
  "nc.us",
  "nd.us",
  "ne.us",
  "nh.us",
  "nj.us",
  "nm.us",
  "nv.us",
  "ny.us",
  "oh.us",
  "ok.us",
  "or.us",
  "pa.us",
  "ri.us",
  "sc.us",
  "sd.us",
  "tn.us",
  "tx.us",
  "ut.us",
  "vt.us",
  "va.us",
  "wa.us",
  "wi.us",
  "wv.us",
  "wy.us",
  "co.ve",
  "ac.vn",
  "ac.yu",
  "co.yu",
  "ac.za",
  "co.za",
  "tm.za",
  "co.zm",
  "ac.zm",
  "co.zw",
  "ac.zw",
  "gov.ac",
  "net.ac",
  "mil.ac",
  "org.ac",
  "nom.ad",
  "net.ae",
  "gov.ae",
  "org.ae",
  "mil.ae",
  "sch.ae",
  "pro.ae",
  "gov.af",
  "edu.af",
  "net.af",
  "com.af",
  "com.ag",
  "org.ag",
  "net.ag",
  "nom.ag",
  "off.ai",
  "com.ai",
  "net.ai",
  "org.ai",
  "gov.al",
  "edu.al",
  "org.al",
  "com.al",
  "net.al",
  "upt.al",
  "com.an",
  "net.an",
  "org.an",
  "edu.an",
  "com.ar",
  "gov.ar",
  "int.ar",
  "mil.ar",
  "net.ar",
  "org.ar",
  "ip6.arpa",
  "uri.arpa",
  "urn.arpa",
  "asn.au",
  "com.au",
  "net.au",
  "org.au",
  "act.au",
  "nsw.au",
  "qld.au",
  "tas.au",
  "vic.au",
  "gov.au",
  "edu.au:",
  "com.aw",
  "com.az",
  "net.az",
  "int.az",
  "gov.az",
  "biz.az",
  "org.az",
  "edu.az",
  "mil.az",
  "com.bb",
  "edu.bb",
  "gov.bb",
  "net.bb",
  "org.bb",
  "com.bd",
  "edu.bd",
  "net.bd",
  "gov.bd",
  "org.bd",
  "mil.bd",
  "gov.bf",
  "com.bm",
  "edu.bm",
  "org.bm",
  "gov.bm",
  "net.bm",
  "com.bn",
  "edu.bn",
  "org.bn",
  "net.bn",
  "com.bo",
  "org.bo",
  "net.bo",
  "gov.bo",
  "gob.bo",
  "edu.bo",
  "mil.bo",
  "int.bo",
  "agr.br",
  "art.br",
  "edu.br",
  "com.br",
  "esp.br",
  "far.br",
  "g12.br",
  "gov.br",
  "imb.br",
  "ind.br",
  "inf.br",
  "mil.br",
  "net.br",
  "org.br",
  "psi.br",
  "rec.br",
  "srv.br",
  "tmp.br",
  "tur.br",
  "etc.br",
  "adm.br",
  "adv.br",
  "arq.br",
  "ato.br",
  "bio.br",
  "bmd.br",
  "cim.br",
  "cng.br",
  "cnt.br",
  "ecn.br",
  "eng.br",
  "eti.br",
  "fnd.br",
  "fot.br",
  "fst.br",
  "ggf.br",
  "jor.br",
  "lel.br",
  "mat.br",
  "med.br",
  "mus.br",
  "not.br",
  "ntr.br",
  "odo.br",
  "ppg.br",
  "pro.br",
  "psc.br",
  "qsl.br",
  "slg.br",
  "trd.br",
  "vet.br",
  "zlg.br",
  "dpn.br",
  "nom.br",
  "com.bs",
  "net.bs",
  "org.bs",
  "com.bt",
  "edu.bt",
  "gov.bt",
  "net.bt",
  "org.bt",
  "org.bw",
  "gov.by",
  "mil.by",
  "com.cd",
  "net.cd",
  "org.cd",
  "com.ch",
  "net.ch",
  "org.ch",
  "gov.ch",
  "com.cn",
  "edu.cn",
  "gov.cn",
  "net.cn",
  "org.cn",
  "com.co",
  "edu.co",
  "org.co",
  "gov.co",
  "mil.co",
  "net.co",
  "nom.co",
  "com.cu",
  "edu.cu",
  "org.cu",
  "net.cu",
  "gov.cu",
  "inf.cu",
  "gov.cx",
  "com.cy",
  "biz.cy",
  "ltd.cy",
  "pro.cy",
  "net.cy",
  "org.cy",
  "com.dm",
  "net.dm",
  "org.dm",
  "edu.dm",
  "gov.dm",
  "edu.do",
  "gov.do",
  "gob.do",
  "com.do",
  "org.do",
  "sld.do",
  "web.do",
  "net.do",
  "mil.do",
  "art.do",
  "com.dz",
  "org.dz",
  "net.dz",
  "gov.dz",
  "edu.dz",
  "pol.dz",
  "art.dz",
  "com.ec",
  "net.ec",
  "fin.ec",
  "med.ec",
  "pro.ec",
  "org.ec",
  "edu.ec",
  "gov.ec",
  "mil.ec",
  "com.ee",
  "org.ee",
  "fie.ee",
  "pri.ee",
  "eun.eg",
  "edu.eg",
  "sci.eg",
  "gov.eg",
  "com.eg",
  "org.eg",
  "net.eg",
  "mil.eg",
  "com.es",
  "nom.es",
  "org.es",
  "gob.es",
  "edu.es",
  "com.et",
  "gov.et",
  "org.et",
  "edu.et",
  "net.et",
  "biz.et",
  "biz.fj",
  "com.fj",
  "net.fj",
  "org.fj",
  "pro.fj",
  "gov.fj",
  "mil.fj",
  "org.fk",
  "gov.fk",
  "nom.fk",
  "net.fk",
  "nom.fr",
  "prd.fr",
  "com.fr",
  "com.ge",
  "edu.ge",
  "gov.ge",
  "org.ge",
  "mil.ge",
  "net.ge",
  "pvt.ge",
  "net.gg",
  "org.gg",
  "com.gh",
  "edu.gh",
  "gov.gh",
  "org.gh",
  "mil.gh",
  "com.gi",
  "ltd.gi",
  "gov.gi",
  "mod.gi",
  "edu.gi",
  "org.gi",
  "com.gn",
  "gov.gn",
  "org.gn",
  "net.gn",
  "com.gp",
  "net.gp",
  "edu.gp",
  "org.gp",
  "com.gr",
  "edu.gr",
  "net.gr",
  "org.gr",
  "gov.gr",
  "com.hk",
  "edu.hk",
  "gov.hk",
  "idv.hk",
  "net.hk",
  "org.hk",
  "com.hn",
  "edu.hn",
  "org.hn",
  "net.hn",
  "mil.hn",
  "gob.hn",
  "com.hr",
  "com.ht",
  "net.ht",
  "pro.ht",
  "org.ht",
  "art.ht",
  "pol.ht",
  "rel.ht",
  "med.ht",
  "edu.ht",
  "org.hu",
  "sex.hu",
  "gov.ie",
  "org.il",
  "net.il",
  "k12.il",
  "gov.il",
  "idf.il",
  "ltd.co.im",
  "plc.co.im",
  "net.im",
  "gov.im",
  "org.im",
  "nic.im",
  "net.in",
  "org.in",
  "gen.in",
  "ind.in",
  "nic.in",
  "edu.in",
  "res.in",
  "gov.in",
  "mil.in",
  "gov.ir",
  "net.ir",
  "org.ir",
  "sch.ir",
  "gov.it",
  "net.je",
  "org.je",
  "edu.jm",
  "gov.jm",
  "com.jm",
  "net.jm",
  "org.jm",
  "com.jo",
  "org.jo",
  "net.jo",
  "edu.jo",
  "gov.jo",
  "mil.jo",
  "mie.jp",
  "per.kh",
  "com.kh",
  "edu.kh",
  "gov.kh",
  "mil.kh",
  "net.kh",
  "org.kh",
  "com.kw",
  "edu.kw",
  "gov.kw",
  "net.kw",
  "org.kw",
  "mil.kw",
  "edu.ky",
  "gov.ky",
  "com.ky",
  "org.ky",
  "net.ky",
  "org.kz",
  "edu.kz",
  "net.kz",
  "gov.kz",
  "mil.kz",
  "com.kz",
  "net.lb",
  "org.lb",
  "gov.lb",
  "edu.lb",
  "com.lb",
  "com.lc",
  "org.lc",
  "edu.lc",
  "gov.lc",
  "com.li",
  "net.li",
  "org.li",
  "gov.li",
  "gov.lk",
  "sch.lk",
  "net.lk",
  "int.lk",
  "com.lk",
  "org.lk",
  "edu.lk",
  "ngo.lk",
  "soc.lk",
  "web.lk",
  "ltd.lk",
  "grp.lk",
  "com.lr",
  "edu.lr",
  "gov.lr",
  "org.lr",
  "net.lr",
  "org.ls",
  "gov.lt",
  "mil.lt",
  "gov.lu",
  "mil.lu",
  "org.lu",
  "net.lu",
  "com.lv",
  "edu.lv",
  "gov.lv",
  "org.lv",
  "mil.lv",
  "net.lv",
  "asn.lv",
  "com.ly",
  "net.ly",
  "gov.ly",
  "plc.ly",
  "edu.ly",
  "sch.ly",
  "med.ly",
  "org.ly",
  "net.ma",
  "gov.ma",
  "org.ma",
  "org.mg",
  "nom.mg",
  "gov.mg",
  "prd.mg",
  "com.mg",
  "edu.mg",
  "mil.mg",
  "com.mk",
  "org.mk",
  "com.mo",
  "net.mo",
  "org.mo",
  "edu.mo",
  "gov.mo",
  "org.mt",
  "com.mt",
  "gov.mt",
  "edu.mt",
  "net.mt",
  "com.mu",
  "biz.mv",
  "com.mv",
  "edu.mv",
  "gov.mv",
  "int.mv",
  "mil.mv",
  "net.mv",
  "org.mv",
  "pro.mv",
  "com.mw",
  "edu.mw",
  "gov.mw",
  "int.mw",
  "net.mw",
  "org.mw",
  "com.mx",
  "net.mx",
  "org.mx",
  "edu.mx",
  "gob.mx",
  "com.my",
  "net.my",
  "org.my",
  "gov.my",
  "edu.my",
  "mil.my",
  "edu.ng",
  "com.ng",
  "gov.ng",
  "org.ng",
  "net.ng",
  "gob.ni",
  "com.ni",
  "edu.ni",
  "org.ni",
  "nom.ni",
  "net.ni",
  "mil.no",
  "vgs.no",
  "fhs.no",
  "com.np",
  "org.np",
  "edu.np",
  "net.np",
  "gov.np",
  "mil.np",
  "gov.nr",
  "edu.nr",
  "biz.nr",
  "org.nr",
  "com.nr",
  "net.nr",
  "cri.nz",
  "gen.nz",
  "iwi.nz",
  "mil.nz",
  "net.nz",
  "org.nz",
  "com.om",
  "edu.om",
  "sch.om",
  "gov.om",
  "net.om",
  "org.om",
  "mil.om",
  "biz.om",
  "pro.om",
  "med.om",
  "com.pa",
  "sld.pa",
  "gob.pa",
  "edu.pa",
  "org.pa",
  "net.pa",
  "abo.pa",
  "ing.pa",
  "med.pa",
  "nom.pa",
  "com.pe",
  "org.pe",
  "net.pe",
  "edu.pe",
  "mil.pe",
  "gob.pe",
  "nom.pe",
  "com.pf",
  "org.pf",
  "edu.pf",
  "com.pg",
  "net.pg",
  "com.ph",
  "gov.ph",
  "com.pk",
  "net.pk",
  "edu.pk",
  "org.pk",
  "fam.pk",
  "biz.pk",
  "web.pk",
  "gov.pk",
  "gob.pk",
  "gok.pk",
  "gon.pk",
  "gop.pk",
  "gos.pk",
  "com.pl",
  "biz.pl",
  "net.pl",
  "art.pl",
  "edu.pl",
  "org.pl",
  "ngo.pl",
  "gov.pl",
  "mil.pl",
  "waw.pl",
  "gda.pl",
  "biz.pr",
  "com.pr",
  "edu.pr",
  "gov.pr",
  "net.pr",
  "org.pr",
  "pro.pr",
  "law.pro",
  "med.pro",
  "cpa.pro",
  "edu.ps",
  "gov.ps",
  "sec.ps",
  "plo.ps",
  "com.ps",
  "org.ps",
  "net.ps",
  "com.pt",
  "edu.pt",
  "gov.pt",
  "int.pt",
  "net.pt",
  "org.pt",
  "net.py",
  "org.py",
  "gov.py",
  "edu.py",
  "com.py",
  "com.ro",
  "org.ro",
  "nom.ro",
  "rec.ro",
  "www.ro",
  "com.ru",
  "net.ru",
  "org.ru",
  "msk.ru",
  "int.ru",
  "gov.rw",
  "net.rw",
  "edu.rw",
  "com.rw",
  "int.rw",
  "mil.rw",
  "gov.rw",
  "com.sa",
  "edu.sa",
  "sch.sa",
  "med.sa",
  "gov.sa",
  "net.sa",
  "org.sa",
  "pub.sa",
  "com.sb",
  "gov.sb",
  "net.sb",
  "edu.sb",
  "com.sc",
  "gov.sc",
  "net.sc",
  "org.sc",
  "edu.sc",
  "com.sd",
  "net.sd",
  "org.sd",
  "edu.sd",
  "med.sd",
  "gov.sd",
  "org.se",
  "fhv.se",
  "mil.se",
  "com.sg",
  "net.sg",
  "org.sg",
  "gov.sg",
  "edu.sg",
  "per.sg",
  "idn.sg",
  "edu.sv",
  "com.sv",
  "gob.sv",
  "org.sv",
  "red.sv",
  "gov.sy",
  "com.sy",
  "net.sy",
  "net.th",
  "biz.tj",
  "com.tj",
  "edu.tj",
  "int.tj",
  "net.tj",
  "org.tj",
  "web.tj",
  "gov.tj",
  "mil.tj",
  "com.tn",
  "gov.tn",
  "org.tn",
  "ind.tn",
  "nat.tn",
  "ens.tn",
  "fin.tn",
  "net.tn",
  "gov.to",
  "gov.tp",
  "com.tr",
  "biz.tr",
  "net.tr",
  "org.tr",
  "web.tr",
  "gen.tr",
  "bbs.tr",
  "tel.tr",
  "gov.tr",
  "bel.tr",
  "pol.tr",
  "mil.tr",
  "k12.tr",
  "edu.tr",
  "com.tt",
  "org.tt",
  "net.tt",
  "biz.tt",
  "pro.tt",
  "edu.tt",
  "gov.tt",
  "gov.tv",
  "edu.tw",
  "gov.tw",
  "mil.tw",
  "com.tw",
  "net.tw",
  "org.tw",
  "idv.tw",
  "com.ua",
  "gov.ua",
  "net.ua",
  "edu.ua",
  "org.ua",
  "gov.uk",
  "ltd.uk",
  "mil.uk",
  "mod.uk",
  "net.uk",
  "nic.uk",
  "nhs.uk",
  "org.uk",
  "plc.uk",
  "sch.uk",
  "jet.uk",
  "nel.uk",
  "nls.uk",
  "sch.uk",
  "dni.us",
  "fed.us",
  "isa.us",
  "nsn.us",
  "edu.uy",
  "gub.uy",
  "org.uy",
  "com.uy",
  "net.uy",
  "mil.uy",
  "com.ve",
  "net.ve",
  "org.ve",
  "web.ve",
  "com.vi",
  "org.vi",
  "edu.vi",
  "gov.vi",
  "com.vn",
  "net.vn",
  "org.vn",
  "edu.vn",
  "gov.vn",
  "int.vn",
  "biz.vn",
  "pro.vn",
  "com.ye",
  "net.ye",
  "org.yu",
  "edu.yu",
  "edu.za",
  "gov.za",
  "law.za",
  "mil.za",
  "nom.za",
  "org.za",
  "alt.za",
  "net.za",
  "ngo.za",
  "web.za",
  "org.zm",
  "gov.zm",
  "sch.zm",
  "org.zw",
  "gov.zw",
  "name.ae",
  "e164.arpa",
  "iris.arpa",
  "priv.at",
  "info.au",
  "conf.au",
  "name.az",
  "info.az",
  "coop.br",
  "info.cy",
  "name.cy",
  "asso.dz",
  "info.ec",
  "name.et",
  "info.et",
  "info.fj",
  "name.fj",
  "asso.fr",
  "gouv.fr",
  "asso.gp",
  "from.hr",
  "name.hr",
  "firm.ht",
  "shop.ht",
  "info.ht",
  "asso.ht",
  "coop.ht",
  "gouv.ht",
  "info.hu",
  "priv.hu",
  "2000.hu",
  "bolt.hu",
  "city.hu",
  "film.hu",
  "news.hu",
  "shop.hu",
  "suli.hu",
  "szex.hu",
  "muni.il",
  "firm.in",
  "gifu.jp",
  "nara.jp",
  "saga.jp",
  "oita.jp",
  "kobe.jp",
  "assn.lk",
  "conf.lv",
  "asso.mc",
  "army.mil",
  "navy.mil",
  "aero.mv",
  "coop.mv",
  "info.mv",
  "name.mv",
  "coop.mw",
  "name.my",
  "stat.no",
  "priv.no",
  "info.nr",
  "geek.nz",
  "govt.nz",
  "info.pl",
  "wroc.pl",
  "lodz.pl",
  "info.pr",
  "isla.pr",
  "name.pr",
  "nome.pt",
  "publ.pt",
  "info.ro",
  "arts.ro",
  "firm.ro",
  "info.sd",
  "sshn.se",
  "fhsk.se",
  "name.tj",
  "intl.tn",
  "info.tn",
  "info.tr",
  "name.tr",
  "info.tt",
  "name.tt",
  "game.tw",
  "ebiz.tw",
  "club.tw",
  "kiev.ua",
  "lviv.ua",
  "sumy.ua",
  "kids.us",
  "info.ve",
  "info.vn",
  "name.vn",
  "city.za",
  "uniti.al",
  "soros.al",
  "inima.al",
  "csiro.au",
  "press.cy",
  "aland.fi",
  "adult.ht",
  "perso.ht",
  "sport.hu",
  "agrar.hu",
  "forum.hu",
  "games.hu",
  "hotel.hu",
  "lakas.hu",
  "media.hu",
  "video.hu",
  "iwate.jp",
  "akita.jp",
  "gunma.jp",
  "chiba.jp",
  "tokyo.jp",
  "fukui.jp",
  "aichi.jp",
  "shiga.jp",
  "kyoto.jp",
  "osaka.jp",
  "hyogo.jp",
  "ehime.jp",
  "kochi.jp",
  "hotel.lk",
  "music.mobi",
  "herad.no",
  "maori.nz",
  "store.ro",
  "brand.se",
  "parti.se",
  "press.se",
  "lutsk.ua",
  "rovno.ua",
  "icnet.uk",
  "tirana.al",
  "school.fj",
  "presse.fr",
  "casino.hu",
  "jogasz.hu",
  "reklam.hu",
  "tozsde.hu",
  "utazas.hu",
  "aomori.jp",
  "miyagi.jp",
  "toyama.jp",
  "nagano.jp",
  "kagawa.jp",
  "sendai.jp",
  "nagoya.jp",
  "museum.mv",
  "museum.mw",
  "museum.no",
  "idrett.no",
  "school.nz",
  "museum.om",
  "krakow.pl",
  "poznan.pl",
  "gdansk.pl",
  "slupsk.pl",
  "lublin.pl",
  "komvux.se",
  "lanarb.se",
  "lanbib.se",
  "crimea.ua",
  "odessa.ua",
  "police.uk",
  "health.vn",
  "school.za",
  "in-addr.arpa",
  "ekloges.cy",
  "erotica.hu",
  "erotika.hu",
  "ibaraki.jp",
  "tochigi.jp",
  "saitama.jp",
  "niigata.jp",
  "tottori.jp",
  "shimane.jp",
  "okayama.jp",
  "fukuoka.jp",
  "okinawa.jp",
  "sapporo.jp",
  "weather.mobi",
  "kommune.no",
  "wroclaw.pl",
  "olsztyn.pl.torun.pl",
  "komforb.se",
  "tourism.tn",
  "donetsk.ua",
  "kharkov.ua",
  "kherson.ua",
  "lugansk.ua",
  "poltava.ua",
  "vinnica.ua",
  "vatican.va",
  "ingatlan.hu",
  "konyvelo.hu",
  "hokkaido.jp",
  "yamagata.jp",
  "kanagawa.jp",
  "ishikawa.jp",
  "shizuoka.jp",
  "wakayama.jp",
  "nagasaki.jp",
  "kumamoto.jp",
  "miyazaki.jp",
  "yokohama.jp",
  "kawasaki.jp",
  "warszawa.pl",
  "szczecin.pl",
  "nikolaev.ua",
  "ternopil.ua",
  "uzhgorod.ua",
  "zhitomir.ua",
  "fukushima.jp",
  "yamanashi.jp",
  "hiroshima.jp",
  "yamaguchi.jp",
  "tokushima.jp",
  "kagoshima.jp",
  "folkebibl.no",
  "bialystok.pl",
  "cherkassy.ua",
  "chernigov.ua",
  "parliament.cy",
  "kitakyushu.jp",
  "fylkesbibl.no",
  "chernovtsy.ua",
  "kirovograd.ua",
  "sebastopol.ua",
  "parliament.uk",
  "zaporizhzhe.ua",
  "khmelnitskiy.ua",
  "naturbruksgymn.se",
  "dnepropetrovsk.ua",
  "kommunalforbund.se",
  "ivano-frankivsk.ua",
  "british-library.uk",
  "national-library-scotland.uk",
] ;

return tld.includes(url) ;
}

回答by Jithin balakrishnan

It loops through the parts of a full hostname and tries to set a cookie on that domain, it will set a cookie at the highest level possible. This function is helpful if you are trying to set the cookie in the base domain

它遍历完整主机名的各个部分并尝试在该域上设置 cookie，它将在可能的最高级别设置 cookie。如果您尝试在基本域中设置 cookie，此功能很有用

Note: test this code in the respective website browser console, otherwise doesn't work.

注意：在相应的网站浏览器控制台中测试此代码，否则不起作用。

function getDomain () {
        var domain =document.domain;
        var i = 0;
        var parts = domain.split('.');
        var value = 'km_' + (new Date()).getTime();
        while (i < (parts.length - 1) && document.cookie.indexOf(value + '=' + value) == -1) {
            domain = parts.slice(-1 - (++i)).join('.');
            document.cookie = value + "=" + value + ";domain=" + domain + ";";
        }
        document.cookie = value + "=;expires=Thu, 01 Jan 1970 00:00:01 GMT;domain=" + domain + ";";
        return domain
}

回答by pguardiario

I had to deal with this today and I settled on:

我今天不得不处理这个问题，我决定：

'www.images.google.co.in'.match(/[^.\s\/]+\.([a-z]{3,}|[a-z]{2}.[a-z]{2})$/)[0]
//=> google.co.in

Note that the rules have changed since many of these answers were submitted.

请注意，自从提交了许多这些答案以来，规则已经发生了变化。

回答by jasonleonhard

How to get base domain from the URL in JavaScript

如何从 JavaScript 中的 URL 获取基本域

document.location.origin

document.location.origin

Result: "https://stackoverflow.com"

结果： "https://stackoverflow.com"

And sometimes you might also want these:

有时您可能还需要这些：

document.location.hostname

document.location.hostname

Result: "stackoverflow.com"

结果： "stackoverflow.com"

document.location.pathname

document.location.pathname

Result: "/questions/6449340/how-to-get-base-domain-from-the-url-in-javascript/58887093"

结果： "/questions/6449340/how-to-get-base-domain-from-the-url-in-javascript/58887093"

回答by nested.condition

(function (){
    var d = document.domain.split('.');
    var i = d.indexOf('google'); 
    return d.slice(i).join('.');
})();