<div id="infinite-scroll">
    <div class="item"></div>
    <div class="item"></div>
    <div class="item"></div>
    <div class="item"></div>
    <div class="item"></div>
    <div class="item"></div>
    <div class="item"></div>
</div>

#infinite-scroll { width: 400px; height:400px; padding:5px; overflow-y: scroll;}
.item { margin:5px; height:150px; background-color: #ccc; }

const $scrollView = document.getElementById("infinite-scroll");
$scrollView.addEventListener("scroll", function (e) {
    const scrollTop = e.target.scrollTop;
    const contentHeight = e.target.scrollHeight - e.target.offsetHeight;
    if (contentHeight <= scrollTop) {
        alert("son!")
    }
})