Shelf input value

jQuery.shelf.js

(function ($) {
    function Shelf(value) {
        var _value = value;

        this.getValue = function () {
            return _value;
        };
        this.setValue = function (value) {
            _value = value;
        };
    }

    var plugin = "shelf",
        methods = {
            hide: function (replacement) {
                return this.each(function () {
                    var $this = $(this),
                        repl = new Shelf(replacement || ""),
                        event = $.Event("hide.shelf");

                    $this
                        .trigger(event, [repl]);

                    if (!event.isDefaultPrevented()) {
                        $this
                            .data($.fn[plugin].dataField, $this.val())
                            .val(repl.getValue())
                            .trigger("hidden.shelf");
                    }
                });
            },
            show: function () {
                return this.each(function () {
                    var $this = $(this),
                        shelf = new Shelf($this.data($.fn[plugin].dataField) || ""),
                        event = $.Event("show.shelf");

                    $this
                        .trigger(event, [shelf]);

                    if (!event.isDefaultPrevented()) {
                        $this
                            .removeData($.fn[plugin].dataField)
                            .val(shelf.getValue())
                            .trigger("shown.shelf", []);
                    }
                });
            }
        };

    $.fn[plugin] = function (method) {
        if (methods[method]) {
            return methods[method].apply(this, Array.prototype.slice.call(arguments, 1));
        } else {
            $.error("Method " + method + " does not exist on jQuery." + plugin);
        }
    };

    $.fn[plugin].dataField = plugin;
})(window.jQuery || window.Zepto);