jquery实现图片翻页效果

代码如下:
$(function($){

    $.fn.changeList = function(options){

        var defaults = {

                    tag : 'li', // tab name

                    subName : '.utilTabSub', // sub class name

                    eventType : 'click', // event type

                    num : 4,

                    showType : 'show' // show effect type

                },

                opts = $.extend({}, defaults, options),

                that = $(this),

                subUl = that.find(opts.subName),

                subItems = subUl.find('li'),

                size = subItems.length,

                liW = subItems.outerWidth(true),

                ulW = liW * size,

                page = size + 1,

                n = opts.num,

                randNum = 0,

                m = 0;

        if(size > n){

            that.find(opts.tag)[opts.eventType](function() {

                randNum = mathRand(n, size);

                subItems.hide();

                $.each(randNum, function (i, el) {

                    subItems.eq(el).fadeIn(800);