How to get base domain from the URL in JavaScript

Question

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 googl

Answer 1

Just just this java script function:

  <script>

    function RedirectUrl() {
      var domain= window.location.hostname;
      var re=/[-\w]+\.(?:[-\w]+\.xn--[-\w]+|[-\w]{3,}|[-\w]+\.[-\w]{2})$/i;
      var Topdomain = re.exec(domain);
      return Topdomain;
    }
    </script>

Answer 2

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

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

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
}

Answer 3

You can try this method

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

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

extractHostname(url); //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>