jquery 自定义模块

// 轮播图模块
(function($) {
    $.fn.carousel = function(options) {
        var settings = $.extend({
            interval: 3000,
            autoplay: true
        }, options);

        return this.each(function() {
            var $carousel = $(this);
            var $items = $carousel.find('.carousel-item');
            var index = 0;

            function showItem(index) {
                $items.hide().eq(index).show();
            }

            function nextItem() {
                index = (index + 1) % $items.length;
                showItem(index);
            }

            if (settings.autoplay) {
                setInterval(nextItem, settings.interval);
            }

            showItem(index);
        });
    };
}(jQuery));

// 使用轮播图模块
$(document).ready(function() {
    $('.carousel').carousel({
        interval: 5000,
        autoplay: true
    });
});

<script src="jquery.js"></script>
<script src="carousel.js"></script>
<script src="main.js"></script>

(function($) {
    // 模块代码
}(jQuery));

// 发布订阅模式
var pubsub = {};
pubsub.publish = function(topic, data) {
    if (!pubsub[topic]) return;
    pubsub[topic].forEach(function(callback) {
        callback(data);
    });
};

pubsub.subscribe = function(topic, callback) {
    if (!pubsub[topic]) pubsub[topic] = [];
    pubsub[topic].push(callback);
};