css动画效果页面滚动到相应位置

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>CSS Scroll Animation</title>
    <style>
        .box {
            width: 100px;
            height: 100px;
            background-color: red;
            margin-top: 500px;
            transition: transform 1s;
        }
        .box.active {
            transform: translateY(-100px);
        }
    </style>
</head>
<body>
    <div class="box"></div>
    <script>
        window.addEventListener('scroll', function() {
            const box = document.querySelector('.box');
            if (window.scrollY > 400) {
                box.classList.add('active');
            } else {
                box.classList.remove('active');
            }
        });
    </script>
</body>
</html>

function handleScroll() {
    const box = document.querySelector('.box');
    if (window.scrollY > 400) {
        box.classList.add('active');
    } else {
        box.classList.remove('active');
    }
    requestAnimationFrame(handleScroll);
}

window.addEventListener('scroll', handleScroll);

function handleScroll() {
    const box = document.querySelector('.box');
    const shouldActivate = window.scrollY > 400;
    if (shouldActivate !== box.classList.contains('active')) {
        if (shouldActivate) {
            box.classList.add('active');
        } else {
            box.classList.remove('active');
        }
    }
}

window.addEventListener('scroll', handleScroll);