Ленивая загрузка картинок

document.addEventListener("DOMContentLoaded", function() {
    const imageObserver = new IntersectionObserver((entries, imgObserver) => {
        entries.forEach((entry) => {
            if (entry.isIntersecting) {

                const lazyImage = entry.target;

                if (lazyImage.tagName == 'IMG') {
                    lazyImage.src = lazyImage.dataset.src;
                } else {
                    lazyImage.style.backgroundImage = 'url('+ lazyImage.dataset.src +')';
                }

                lazyImage.classList.remove("gr_images_lazy_load");
                imgObserver.unobserve(lazyImage);
            }
        })
    });
    const arr = document.querySelectorAll(".gr_images_lazy_load");

    arr.forEach((v) => {
        imageObserver.observe(v);
    })
});