js轮播图左右按钮切换代码

JavaScript 轮播图的左右按钮切换功能通常涉及到 DOM 操作、事件监听和定时器等概念。以下是一个简单的示例代码，展示了如何实现一个基本的轮播图，并包含左右按钮的切换功能。

基础概念

DOM 操作：通过 JavaScript 操作 HTML 文档对象模型，实现对页面元素的增删改查。
事件监听：为按钮添加点击事件，当用户点击按钮时触发相应的函数。
定时器：使用 setInterval 或 setTimeout 实现自动轮播效果。

示例代码

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>轮播图示例</title>
    <style>
        .carousel {
            width: 600px;
            overflow: hidden;
            position: relative;
        }
        .carousel-inner {
            display: flex;
            transition: transform 0.5s ease-in-out;
        }
        .carousel-item {
            min-width: 100%;
            box-sizing: border-box;
        }
        .carousel-item img {
            width: 100%;
            display: block;
        }
        .carousel-control {
            position: absolute;
            top: 50%;
            transform: translateY(-50%);
            background: rgba(0, 0, 0, 0.5);
            color: white;
            border: none;
            padding: 10px;
            cursor: pointer;
        }
        .prev {
            left: 10px;
        }
        .next {
            right: 10px;
        }
    </style>
</head>
<body>
    <div class="carousel" id="carousel">
        <div class="carousel-inner" id="carouselInner">
            <div class="carousel-item"><img src="image1.jpg" alt="Image 1"></div>
            <div class="carousel-item"><img src="image2.jpg" alt="Image 2"></div>
            <div class="carousel-item"><img src="image3.jpg" alt="Image 3"></div>
        </div>
        <button class="carousel-control prev" id="prevBtn">Prev</button>
        <button class="carousel-control next" id="nextBtn">Next</button>
    </div>

    <script>
        const carouselInner = document.getElementById('carouselInner');
        const items = document.querySelectorAll('.carousel-item');
        const prevBtn = document.getElementById('prevBtn');
        const nextBtn = document.getElementById('nextBtn');
        let currentIndex = 0;

        function updateCarousel() {
            const offset = -currentIndex * 100;
            carouselInner.style.transform = `translateX(${offset}%)`;
        }

        prevBtn.addEventListener('click', () => {
            currentIndex = (currentIndex > 0) ? currentIndex - 1 : items.length - 1;
            updateCarousel();
        });

        nextBtn.addEventListener('click', () => {
            currentIndex = (currentIndex < items.length - 1) ? currentIndex + 1 : 0;
            updateCarousel();
        });

        // 自动轮播（可选）
        setInterval(() => {
            currentIndex = (currentIndex < items.length - 1) ? currentIndex + 1 : 0;
            updateCarousel();
        }, 3000);
    </script>
</body>
</html>