估计网上能查到的最多的两种图片延迟加载方法就是jquery.scrollLoading.js与jquery.lazyload.js了，其中jquery.lazyload.js的调用方法因为有网友爆出的bug，改进了调用方法，另外修改了关于浏览器IE版本的判断。以下直接为代码，并没有什么修改。做个记号。
两种方法都采用jquery-1.8.3.min.js版本。
jquery.scrollLoading方法
html
<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8"/>
<title></title>
<script src="js/jquery-1.8.3.min.js"></script>
<script src="Scripts/jquery.scrollLoading.js"></script>
<script>
$(function(){
$(".scrollLoading").scrollLoading();
});
</script>
</head>
<body>
<h2>页面图片等元素滚动动态加载技术</h2>
<br />
<img class="scrollLoading" data-url="images/mm/00_00.jpg" src="data:images/pixel.gif" width="" height="" style="background:url(images/loading.gif) no-repeat center;" />
<br /><br /><br /><br /><br /><br />
<img class="scrollLoading" data-url="images/mm/00_01.jpg" src="data:images/pixel.gif" width="" height="" style="background:url(images/loading.gif) no-repeat center;" />
<br /><br /><br /><br /><br /><br />
<img class="scrollLoading" data-url="images/mm/00_02.jpg" src="data:images/pixel.gif" width="" height="" style="background:url(images/loading.gif) no-repeat center;" />
<br /><br /><br /><br /><br /><br />
<img class="scrollLoading" data-url="images/mm/00_03.jpg" src="data:images/pixel.gif" width="" height="" style="background:url(images/loading.gif) no-repeat center;" />
<br /><br /><br /><br /><br /><br />
<img class="scrollLoading" data-url="images/mm/00_04.jpg" src="data:images/pixel.gif" width="" height="" style="background:url(images/loading.gif) no-repeat center;" />
<br /><br /><br /><br /><br /><br />
<img class="scrollLoading" data-url="images/mm/00_05.jpg" src="data:images/pixel.gif" width="" height="" style="background:url(images/loading.gif) no-repeat center;" />
<br /><br /><br /><br /><br /><br />
<img class="scrollLoading" data-url="images/mm/00_06.jpg" src="data:images/pixel.gif" width="" height="" style="background:url(images/loading.gif) no-repeat center;" />
<br /><br /><br /><br /><br /><br />
<img class="scrollLoading" data-url="images/mm/00_07.jpg" src="data:images/pixel.gif" width="" height="" style="background:url(images/loading.gif) no-repeat center;" />
<br /><br /><br /><br /><br /><br />
<img class="scrollLoading" data-url="images/mm/00_08.jpg" src="data:images/pixel.gif" width="" height="" style="background:url(images/loading.gif) no-repeat center;" />
<br /><br /><br /><br /><br /><br />
<img class="scrollLoading" data-url="images/mm/00_09.jpg" src="data:images/pixel.gif" width="" height="" style="background:url(images/loading.gif) no-repeat center;" />
</body>
</html>
js
/*!
* jquery.scrollLoading.js
* by zhangxinxu http://www.zhangxinxu.com/wordpress/?p=1259
* 2010-11-19 v1.0
* 2012-01-13 v1.1 偏移值计算修改 position → offset
* 2012-09-25 v1.2 增加滚动容器参数, 回调参数
* 2014-08-11 v1.3 修复设置滚动容器参数一些bug, 以及误删posb值的一些低级错误
*/
(function($) {
$.fn.scrollLoading = function(options) {
var defaults = {
attr: "data-url",
container: $(window),
callback: $.noop
};
var params = $.extend({}, defaults, options || {});
params.cache = [];
$(this).each(function() {
var node = this.nodeName.toLowerCase(), url = $(this).attr(params["attr"]);
//重组
var data = {
obj: $(this),
tag: node,
url: url
};
params.cache.push(data);
}); var callback = function(call) {
if ($.isFunction(params.callback)) {
params.callback.call(call.get());
}
};
//动态显示数据
var loading = function() { var contHeight = params.container.height();
if (params.container.get() === window) {
contop = $(window).scrollTop();
} else {
contop = params.container.offset().top;
} $.each(params.cache, function(i, data) {
var o = data.obj, tag = data.tag, url = data.url, post, posb; if (o) {
post = o.offset().top - contop, posb = post + o.height();
if ((post >= && post < contHeight) || (posb > && posb <= contHeight)) {
if (url) {
//在浏览器窗口内
if (tag === "img") {
//图片，改变src
callback(o.attr("src", url));
} else {
o.load(url, {}, function() {
callback(o);
});
}
} else {
// 无地址，直接触发回调
callback(o);
}
data.obj = null;
}
}
});
}; //事件触发
//加载完毕即执行
loading();
//滚动执行
params.container.bind("scroll", loading);
};
})(jQuery);
jquery.lazyload.js方法
html
<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8"/>
<title></title>
<script src="js/jquery-1.8.3.min.js"></script>
<script src="js/jquery.lazyload.js"></script>
<script>
function checkbrowse() {
var ua = navigator.userAgent.toLowerCase();
var is = (ua.match(/\b(chrome|opera|safari|msie|firefox)\b/) || ['', 'mozilla'])[1];
var r = '(?:' + is + '|version)[\\/: ]([\\d.]+)';
var v = (ua.match(new RegExp(r)) || [])[1];
jQuery.browser.is = is;
jQuery.browser.ver = v;
return {
'is': jQuery.browser.is,
'ver': jQuery.browser.ver
}
}
var public = checkbrowse();
var showeffect = "";
if ((public['is'] == 'msie' && public['ver'] < 8.0)) {
showeffect = "show"
} else {
showeffect = "fadeIn"
} $(function(){
$("img").lazyload({
threshold : 200,
effect : showeffect
});
});
</script>
</head>
<body>
<h2>页面图片等元素滚动动态加载技术</h2>
<br />
<img original="images/mm/1.jpg" src="data:images/loading.gif" width="630" height="420" />
<br /><br /><br /><br /><br /><br />
<img original="images/mm/2.jpg" src="data:images/loading.gif" width="630" height="420" />
<br /><br /><br /><br /><br /><br />
<img original="images/mm/3.jpg" src="data:images/loading.gif" width="630" height="420" />
<br /><br /><br /><br /><br /><br />
<img original="images/mm/4.jpg" src="data:images/loading.gif" width="630" height="420" />
<br /><br /><br /><br /><br /><br />
<img original="images/mm/5.jpg" src="data:images/loading.gif" width="630" height="420" />
<br /><br /><br /><br /><br /><br />
<img original="images/mm/6.jpg" src="data:images/loading.gif" width="630" height="420" />
<br /><br /><br /><br /><br /><br />
<img original="images/mm/7.jpg" src="data:images/loading.gif" width="630" height="420" />
<br /><br /><br /><br /><br /><br />
<img original="images/mm/8.jpg" src="data:images/loading.gif" width="630" height="420" />
<br /><br /><br /><br /><br /><br />
<img original="images/mm/9.jpg" src="data:images/loading.gif" width="630" height="420" />
<br /><br /><br /><br /><br /><br />
<img original="images/mm/10.jpg" src="data:images/loading.gif" width="630" height="420" />
</body>
</html>
js
/*
* Lazy Load - jQuery plugin for lazy loading images
*
* Copyright (c) 2007-2009 Mika Tuupola
*
* Licensed under the MIT license:
* http://www.opensource.org/licenses/mit-license.php
*
* Project home:
* http://www.appelsiini.net/projects/lazyload
*
* Version: 1.5.0
*
*/
(function ($) {
//判断客户端浏览器
function checkbrowse() {
var ua = navigator.userAgent.toLowerCase();
var is = (ua.match(/\b(chrome|opera|safari|msie|firefox)\b/) || ['', 'mozilla'])[1];
var r = '(?:' + is + '|version)[\\/: ]([\\d.]+)';
var v = (ua.match(new RegExp(r)) || [])[1];
jQuery.browser.is = is;
jQuery.browser.ver = v;
return {
'is': jQuery.browser.is,
'ver': jQuery.browser.ver
}
} var public = checkbrowse();
$.fn.lazyload = function (options) {
var showeffect = "";
if ((public['is'] == 'msie' && public['ver'] < 8.0)) {
showeffect = "show";
} else {
showeffect = "fadeIn";
}
var settings = {
threshold: 0,
failurelimit: 0,
event: "scroll",
effect: showeffect,
container: window
}; if (options) {
$.extend(settings, options);
}
/* Fire one scroll event per scroll. Not one scroll event per image. */
var elements = this;
if ("scroll" == settings.event) {
$(settings.container).bind("scroll", function (event) {
var counter = 0;
elements.each(function () {
if ($.abovethetop(this, settings) ||
$.leftofbegin(this, settings)) {
/* Nothing. */
} else if (!$.belowthefold(this, settings) &&
!$.rightoffold(this, settings)) {
$(this).trigger("appear");
} else {
if (counter++ > settings.failurelimit) {
return false;
}
}
});
/* Remove image from array so it is not looped next time. */
var temp = $.grep(elements, function (element) {
return !element.loaded;
});
elements = $(temp);
});
}
this.each(function () {
var self = this;
//删除的代码
/* When appear is triggered load original image. */
$(self).one("appear", function () {
if (!this.loaded) {
$("<img />").bind("load", function () {
$(self).hide().attr("src", $(self).attr("original"))[settings.effect](settings.effectspeed);
self.loaded = true;
}).attr("src", $(self).attr("original"));
};
});
/* When wanted event is triggered load original image */
/* by triggering appear. */
if ("scroll" != settings.event) {
$(self).bind(settings.event, function (event) {
if (!self.loaded) {
$(self).trigger("appear");
}
});
}
});
/* Force initial check if images should appear. */
$(settings.container).trigger(settings.event);
return this;
};
/* Convenience methods in jQuery namespace. */
/* Use as $.belowthefold(element, {threshold : 100, container : window}) */
$.belowthefold = function (element, settings) {
if (settings.container === undefined || settings.container === window) {
var fold = $(window).height() + $(window).scrollTop();
} else {
var fold = $(settings.container).offset().top + $(settings.container).height();
}
return fold <= $(element).offset().top - settings.threshold;
};
$.rightoffold = function (element, settings) {
if (settings.container === undefined || settings.container === window) {
var fold = $(window).width() + $(window).scrollLeft();
} else {
var fold = $(settings.container).offset().left + $(settings.container).width();
}
return fold <= $(element).offset().left - settings.threshold;
};
$.abovethetop = function (element, settings) {
if (settings.container === undefined || settings.container === window) {
var fold = $(window).scrollTop();
} else {
var fold = $(settings.container).offset().top;
}
return fold >= $(element).offset().top + settings.threshold + $(element).height();
};
$.leftofbegin = function (element, settings) {
if (settings.container === undefined || settings.container === window) {
var fold = $(window).scrollLeft();
} else {
var fold = $(settings.container).offset().left;
}
return fold >= $(element).offset().left + settings.threshold + $(element).width();
};
/* Custom selectors for your convenience. */
/* Use as $("img:below-the-fold").something() */
$.extend($.expr[':'], {
"below-the-fold": "$.belowthefold(a, {threshold : 0, container: window})",
"above-the-fold": "!$.belowthefold(a, {threshold : 0, container: window})",
"right-of-fold": "$.rightoffold(a, {threshold : 0, container: window})",
"left-of-fold": "!$.rightoffold(a, {threshold : 0, container: window})"
});
})(jQuery);