图片懒加载插件

<script src="https://rawgit.com/tuupola/jquery_lazyload/2.x/lazyload.js"></script>
<img class="lazyload" src="thumbnail/example.jpg" data-src="example.jpg" />
<script>
    window.addEventListener("load", function (event) {
        let timeout = setTimeout(function () {
            azyload();
        }, 5000);
    });
</script>