For suspicious types (including me):

    javascript:(function(){javascript:(function() {
      var xhr = new XMLHttpRequest();
      xhr.onreadystatechange = function() {
        if (xhr.readyState === 4) {
          alert('HTTP Status Code: ' + xhr.status);
        }
      };
      xhr.open('GET', window.location.href, true);
      xhr.send();
    })();})();