六月份Chrome增加了对loading属性的支持，但对我来说不起作用。当图像不在viewport中时，它正在加载。

1. My network info in DevTools
   1.用户代理：Chrome/75.0.3770.80
   1.在Chrome：//flags中启用延迟图片加载
   1.我的测试页面：

<p style="margin-bottom: 1000px;">Please scroll down. The image is below the viewport.</p>
<p style="margin-bottom: 1000px;">Way to go&hellip;</p>

<h4>Lazy cat loaded lazily</h4>
<p>If your browser supports native lazy-loading, it loads the first 2 kB of the image in order to display a
    placeholder. Then, it loads the full-size image.</p>
<p>If your browser does not support native lazy-loading, it loads the lazysizes library and sets the
    <code>img</code>'s <code>src</code> to a low-quality image placeholder, which is also around 2 kB in size. Then,
    it loads the full-size image.</p>
<div class="alert alert-warning">The native lazy-loading's 2 kB range request do not work from within Codepen.
    However, you can make this work by copying this to an empty HTML file on your computer.</div>
<!-- <img src="https://demo.tiny.pictures/native-lazy-loading/lazy-cat.jpg?width=500"
    loading="lazy" alt="Lazy cat loaded lazily"> -->
<img src="images/article/photo.jpg" loading="lazy" alt="Lazy turtle">

<script>
    if ('loading' in HTMLImageElement.prototype) {
        console.log('YES');
    } else {
        console.log('NO');
    }
</script>

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你能告诉我，我做错了什么，或者这个属性是原始的，不工作？