[Aetae]

var comment = (function createCurrentURLComment(window){
  var prefix = ' saved from url=',
      postfix = ' ',
      document = window.document,
      location = window.location,
      comment = document.createComment(prefix + location.href + postfix);
   
  document.documentElement.before(comment);

  window.addEventListener('popstate', function(){
    comment.data = prefix + location.href + postfix;
  }, false);
   
  return comment
}(window));