<link rel="stylesheet" type="text/css" media="screen" href="path/noname-gallery.css">

<script src="path/noname-gallery.js"></script>

<div id="imgBox">
    <img src="" alt="">
    <img src="" alt="">
    <img src="" alt="">
    <img src="" alt="">
    <img src="" alt="">
    <img src="" alt="">
</div>

<script>
    const imgBox = document.querySelector('#imgBox);
    const imgList = document.querySelectorAll('#imgBox img');

    // event delegate
    imgBox.addEventListener('click', function (e) {
        if (e.target.tagName === 'IMG') {
            const options = {
                list: [].slice.call(imgList, 0),
                index: [].indexOf.call(e.target.parentNode.children, e.target)
            }
            // init and open gallery
            const gallery = new NonameGallery(options);
            gallery.init();
        }
    });
</script>