<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Document</title>
<style>
div{
300px;
height: 300px;
margin-bottom: 20px;
}
</style>
</head>
<body>
<div>
<img src="http://www.zj1024.com/images/loading.gif" data-src="http://www.zj1024.com/item/works/shuyuan/images/shuyuan6.jpg">
</div>
<div>
<img src="http://www.zj1024.com/images/loading.gif" data-src="http://www.zj1024.com/item/works/shuyuan/images/shuyuan1.jpg">
</div>
<div>
<img src="http://www.zj1024.com/images/loading.gif" data-src="http://www.zj1024.com/item/works/shuyuan/images/shuyuan6.jpg">
</div>
<div>
<img src="http://www.zj1024.com/images/loading.gif" data-src="http://www.zj1024.com/item/works/shuyuan/images/shuyuan1.jpg">
</div>
<div>
<img src="http://www.zj1024.com/images/loading.gif" data-src="http://www.zj1024.com/item/works/shuyuan/images/shuyuan6.jpg">
</div>
<div>
<img src="http://www.zj1024.com/images/loading.gif" data-src="http://www.zj1024.com/item/works/shuyuan/images/shuyuan1.jpg">
</div>
<div>
<img src="http://www.zj1024.com/images/loading.gif" data-src="http://www.zj1024.com/item/works/shuyuan/images/shuyuan6.jpg">
</div>
<div>
<img src="http://www.zj1024.com/images/loading.gif" data-src="http://www.zj1024.com/item/works/shuyuan/images/shuyuan1.jpg">
</div>
<div>
<img src="http://www.zj1024.com/images/loading.gif" data-src="http://www.zj1024.com/item/works/shuyuan/images/shuyuan6.jpg">
</div>
<div>
<img src="http://www.zj1024.com/images/loading.gif" data-src="http://www.zj1024.com/item/works/shuyuan/images/shuyuan1.jpg">
</div>
</body>
<script>
;(function(window,document){
var num = document.getElementsByTagName('img').length;
var img = document.getElementsByTagName('img');
var n = 0; //存储图片加载到的位置，避免每次都从第一张图片开始遍历
lazyload(); //页面载入完毕加载可是区域内的图片
function lazyload() { //监听页面滚动事件
var seeHeight = document.documentElement.clientHeight; //可见区域高度
var scrollTop = document.documentElement.scrollTop || document.body.scrollTop; //滚动条距离顶部高度
for (var i = n; i < num; i++) {
if (img[i].offsetTop < seeHeight + scrollTop) {
if (img[i].getAttribute("src") == "http://www.zj1024.com/images/loading.gif") {
img[i].src = img[i].getAttribute("data-src");
}
n = i + 1;
}
}
}
// 简单的节流函数
//fun 要执行的函数
//delay 延迟
//time 在time时间内必须执行一次
function throttle(fun, delay, time) {
var timeout,
startTime = new Date();
return function() {
var context = this,
args = arguments,
curTime = new Date();
clearTimeout(timeout);
// 如果达到了规定的触发时间间隔，触发 handler
if (curTime - startTime >= time) {
fun.apply(context, args);
startTime = curTime;
// 没达到触发间隔，重新设定定时器
} else {
timeout = setTimeout(function(){
fun.apply(context, args);
}, delay);
}
};
};
// 实际想绑定在 scroll 事件上的 handler
// 采用了节流函数
window.addEventListener('scroll',throttle(lazyload,500,1000));
})(window,document);
</script>
</html>