jQuery Valuechange event and handler

jquery.valuechange.js

/* Valuechange event and handler
 * See: http://learn.jquery.com/events/event-extensions/
 */
(function($) {

    var name = "valuechange";

    $.event.special[name] = {

        // Event is bound
        add: function(handleObj) {

            var eventNames = ["input", "propertychange", "drop", "paste", "keyup"],
                namespace = "." + name + (handleObj.namespace ? '.' + handleObj.namespace : ''),
                element = $(this);

            var events = $.map(eventNames, function(eventName) {
                return eventName + namespace;
            }).join(" ");

            // bind events raised by value changing
            element.on(events, handleObj.selector, function(event) {

                var 
                    value = event.target.value,
                    data = jQuery.data(event.target),
                    previousValue = (data.previousValue || "");

                if (previousValue !== value) {
                    event.type = handleObj.origType;
                    $.event.dispatch.apply(this, arguments);
                    event.type = handleObj.type;
                    data.previousValue = value;
                }
            });
        },

        // Event is unbound
        remove: function(handleObj) {

            // unbind events raised by value changing
            var namespace = "." + name + (handleObj.namespace ? '.' + handleObj.namespace : ''),
                element = $(this);

            element.off(namespace, handleObj.selector);
        }
    };
})(jQuery);