jquery.on.off.js

(function($){
"use strict";

var undelegateOrUnbind = function(events, selector, handler){
  return ($.type(selector) !== 'string') ? this.unbind(events, handler) : this.undelegate(selector, events, handler);
};

// Stub in "on/off" for jQuery >= 1.4.3 and < 1.7
if (!$.fn.on && $.fn.delegate && ($.fn.jquery !== '1.4.2')) {
  $.fn.on = function(events, selector, data, handler){
    var $collection = this;
    var useBind = $.type(selector) !== 'string';
    // Handle either a string of event names or a map of events-and-callbacks for the 1st parameter
    if ($.isPlainObject(events)) {
      if (useBind) {
        return $collection.bind(events);
      }
      if ($.isPlainObject(data)) {
        $.each(events, function(eventName, callback){
          $collection.delegate(selector, eventName, data, callback);
        });
        return $collection;
      }
      return $collection.delegate(selector, events);
    }
    if (useBind) {
      return $.fn.bind.apply($collection, arguments);
    }
    return $collection.delegate(selector, events, data, handler);
  };
  $.fn.off = function(events, selector, handler){
    var $collection = this;
    if ($.isPlainObject(events)) {
      $.each(events, function(eventName, callback){
        undelegateOrUnbind.apply($collection, [eventName, selector, callback]);
      });
      return $collection;
    }
    return undelegateOrUnbind.apply($collection, arguments);
  };
}

})(jQuery);