jquery sortable ul在ul不工作

Question

有点困惑。我有一大堆代码可以对嵌套的li进行排序。我将代码复制到另一个页面，只是更改了一些类名以匹配新的页面元素。对于我的生活，我无法弄清楚为什么相同的代码不能在新页面上工作。这是代码：

var is_sortable = true;

$(function () {
    $('.packaging_move').bind("mousedown", packaging_add_sort);

    function packaging_add_sort() {
        //CHECK TO SEE IF THERE IS AN ACTIVE SORTABLE
        if (is_sortable) {
            //GET THE PARENT AND CURRENT ELEMENTS TO THE CLICKED ITEM
            var parent = $(this).parent('div').parent('div').parent('li').parent('ul');
            var current = $(this).parent('div').parent('div').parent('li');
            //MAKE TRANSPARENT
            current.animate({
                opacity: 0.60
            }, 100);
            //PREVENT ANOTHER SORTABLE
            is_sortable = false;

            //CREATE SORTABLE
            parent.sortable({
                axis: 'y',
                update: function () {
                    var parent_id = parent.attr("id");
                    var list = parent.sortable('serialize');
                    $.post("index.php?plugin=packaging&page=index", {
                        action: "packaging_rank",
                        parent: parent_id,
                        items: list
                    });
                    parent.sortable('destroy');
                    is_sortable = true;
                },
                stop: function () {
                    current.animate({
                        opacity: 1.0
                    }, 100);
                    parent.sortable('destroy');
                    is_sortable = true;
                },
            }).disableSelection();

            //IF THERE IS AN EXISTING SORTABLE SHOW ERROR
        } else {
            zlcms_alert("Sorting Error", "You currently have an instance of sorting initiated.  You may only sort one item at a time. Please complete the previous sort and try again.")
        }
    }
}