scroll_fadein.js

window.addEventListener("load", () => {
    window.onscroll = (event) => {
        const objs = document.getElementsByClassName("scroll-fadein")
        for (let i = 0; i < objs.length; i++) {
            const bottomObj = objs[i].offsetTop + objs[i].scrollHeight;
            const bottomWindow = window.scrollY + window.outerHeight;
            if (bottomWindow > bottomObj) {
                objs[i].style.opacity = "1"
            }
        }
    }

})