06-scroll-Animation（滚动动画效果）

html

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <link rel="stylesheet" href="style.css">
</head>
<body>
    <h1>Scroll to see the animation</h1>
    <div class="box">
        <h2>Content</h2>
    </div>
    <div class="box">
        <h2>Content</h2>
    </div>
    <div class="box">
        <h2>Content</h2>
    </div>
    <div class="box">
        <h2>Content</h2>
    </div>
    <div class="box">
        <h2>Content</h2>
    </div>
    <div class="box">
        <h2>Content</h2>
    </div>
    <div class="box">
        <h2>Content</h2>
    </div>
    <div class="box">
        <h2>Content</h2>
    </div>
    <div class="box">
        <h2>Content</h2>
    </div>
    <div class="box">
        <h2>Content</h2>
    </div>
    <div class="box">
        <h2>Content</h2>
    </div>
    <div class="box">
        <h2>Content</h2>
    </div>
    <div class="box">
        <h2>Content</h2>
    </div>
    <div class="box">
        <h2>Content</h2>
    </div>

    <script src="./script.js"></script>
</body>
</html>

css

@import url('https://fonts.googleapis.com/css2?family=Roboto:wght@400;700&display=swap');

* {
  box-sizing: border-box;
}

body{
    background-color: #efedd6;
    font-family: 'Roboto',sans-serif;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    margin: 0;
    overflow-x: hidden;
}

h1{
    margin: 10px;
}

.box{
    background-color: steelblue;
    color: #fff;
    display: flex;
    align-items: center;
    justify-content: center;
    width: 400px;
    height: 200px;
    margin: 10px;
    border-radius: 10px;
    box-shadow: 2px 4px 5px rgba(0,0,0,0.3);
    transform: translateX(400%);
    transition: transform 0.4s ease;
}

.box:nth-of-type(even){
    transform: translateX(-400%);
}

.box.show{
    transform: translateX(0);
}

.box h2{
    font-size: 45px;
}

const boxes = document.querySelectorAll('.box')

window.addEventListener('scroll',checkBoxes)

checkBoxes()

function checkBoxes(){
    const triggerBottom = window.innerHeight / 5 * 4

    boxes.forEach(box=>{
        const boxTop = box.getBoundingClientRect().top
        if(boxTop < triggerBottom){
            box.classList.add('show')
        }else{
            box.classList.remove('show')
        }
    })
}