Get top-level domain (TLD) of current page

getTLD.js

function getTLD(){
  var cookieName = '_tmp_detect_tld',
      globalNamespacePageloadCache = cookieName;
  return window[globalNamespacePageloadCache] || ( window[globalNamespacePageloadCache] = (function(){
    var i, domain, parts = location.hostname.split('.'), 
        UNDEFINED = '{{UNDEFINED}}', cKeyValPair, c;
    if( window.navigator && navigator.cookieEnabled === false ){ return UNDEFINED+' cookies disabled'; }
    for( i=parts.length-1; i>=0; i-- ){
      domain = parts.slice(i).join('.');
      cKeyValPair = cookieName+'_'+domain+'=1';
      document.cookie = c = cKeyValPair+';domain=.'+domain+';path=/;SameSite=None;Secure;';
      if( document.cookie.indexOf(cKeyValPair)>-1 ){
        document.cookie = c+'expires=Thu, 01 Jan 1970 00:00:01 GMT;';
        // Session cookie might not be deleted in Chrome
        //if( document.cookie.indexOf(cKeyValPair)>-1 ){ return UNDEFINED+' failed to remove cookie'; }
        return domain;
      }
    }
    return UNDEFINED;
  })());
}