cms-system/cms-editor/templates/default_v5/assets/js/image.js

const images = document.querySelectorAll("img");

// 传给IntersectionObserver的回调函数
// 在目标元素能看见时触发一次，目标元素看不见了时再触发一次
const observer = new IntersectionObserver(entries => {
    entries.forEach(entry => {
        if (entry.isIntersecting) {
            const image = entry.target;
            const data_src = image.getAttribute("data-src");
            image.setAttribute("src", data_src);
            // 图片被加载后取消观察
            observer.unobserve(image);
        }
    });
});

images.forEach(image => {
    observer.observe(image);
});