Verify internet connection

hasConnection.js

const HTTP_STATUS_OK = 200,
      HTTP_STATUS_NOT_MODIFIED = 304,
      HTTP_STATUS_MULTIPLE_CHOICE = 300,
      HTTP_METHOD = "HEAD",
      hasConnection = (host = window.location.protocol + "//" + window.location.hostname) => {
        if(window.navigator)
          return navigator.onLine;
        else{
          const xhr = new (window.ActiveXObject || XMLHttpRequest)("Microsoft.XMLHTTP");
          xhr.open(HTTP_METHOD, host, false);
          try{
            xhr.send();
            return (xhr.status >= HTTP_STATUS_OK && (xhr.status < HTTP_STATUS_MULTIPLE_CHOICE || xhr.status === HTTP_STATUS_NOT_MODIFIED));
          }catch(e){
            return false;
          }
        }
        return false;
};

Segundo commit atendendo ao pedido do meu amigo Marcelo "Murchila"