example.js

// before
$(document).delegate("#login-form", "submit:successful", function(e) {
  var subEvent = new jQuery.Event("login:success");

  $(this).trigger(subEvent);

  if (subEvent.isDefaultPrevented()) {
    e.preventDefault();
  }
});

// after
$(document).delegate("#login-form", "submit:successful", function(e) {
  $(this).trigger(e.sub('login:success'));
});

jquery_sub_event.js

(function() {
  Event.prototype.sub = function(type){
    var subEvent = new Event(this);
    subEvent.type = type;
    return subEvent;
  };
})(jQuery.Event);