Jquery实现逐屏加载图片

引用jquery.scrollLoading.js

$(document).ready(function () {

            //实现图片慢慢浮现出来的效果

            $("img").load(function () {

                //图片默认隐藏

                $(this).hide();

                //使用fadeIn特效

                $(this).fadeIn("5000");

            });

            // 异步加载图片，实现逐屏加载图片

            $(".scrollLoading").scrollLoading();

});

//data-url表示将要异步加载的图片，src表示首先加载的图片

<img class="scrollLoading" data-url="image/logo.jpg" src="/Images/120.gif" />

jquery.scrollLoading.js内容

(function ($) {

    // alert($.fn.scrollLoading);

    $.fn.scrollLoading = function (options) {

        var defaults = {

            attr: "data-url"

        };

        var params = $.extend({}, defaults, options || {});

        params.cache = [];

        $(this).each(function () {

            var node = this.nodeName.toLowerCase(), url = $(this).attr(params["attr"]);

            if (!url) { return; }

            var data = {

                obj: $(this),

                tag: node,

                url: url

            };

            params.cache.push(data);

        });

        var loading = function () {

            var st = $(window).scrollTop(), sth = st + $(window).height();

            $.each(params.cache, function (i, data) {

                var o = data.obj, tag = data.tag, url = data.url;

                if (o) {

                    post = o.position().top; posb = post + o.height();

                    if ((post > st && post < sth) || (posb > st && posb < sth)) {

                        if (tag === "img") {

                            o.attr("src", url);

                        } else {

                            o.load(url);

                        }

                        data.obj = null;

                    }

                }

            });

            return false;

        };

        loading();

        $(window).bind("scroll", loading);

    };

})(jQuery);