JavaScript轮播图实现步骤详解

  

    

      
    
    

      
    
    

      
    
  
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>

.carousel {
  position: relative;
  width: 600px;
  height: 400px;
  overflow: hidden;
  margin: 0 auto;
}
.carousel-inner {
display: flex;
width: 100%;
height: 100%;
transition: transform 0.5s ease;
}
.carousel-item {
min-width: 100%;
height: 100%;
}
.carousel-item img {
width: 100%;
height: 100%;
object-fit: cover;
}
.carousel-item:not(.active) {
display: none;
}
.carousel-prev, .carousel-next {
position: absolute;
top: 50%;
transform: translateY(-50%);
background: rgba(0,0,0,0.5);
color: white;
border: none;
padding: 10px;
cursor: pointer;
}
.carousel-prev { left: 10px; }
.carousel-next { right: 10px; }
.carousel-indicators {
position: absolute;
bottom: 10px;
left: 50%;
transform: translateX(-50%);
display: flex;
gap: 8px;
}
.carousel-indicators span {
width: 12px;
height: 12px;
background: #ccc;
border-radius: 50%;
cursor: pointer;
}
.carousel-indicators span.active {
background: white;
}

class Carousel {
  constructor(container) {
    this.container = document.querySelector(container);
    this.items = this.container.querySelectorAll('.carousel-item');
    this.indicators = this.container.querySelectorAll('.carousel-indicators span');
    this.prevBtn = this.container.querySelector('.carousel-prev');
    this.nextBtn = this.container.querySelector('.carousel-next');
this.currentIndex = 0;
this.interval = null;
this.autoPlayInterval = 3000; // 自动播放间隔

this.init();
}
init() {
this.showItem(this.currentIndex);
this.bindEvents();
this.startAutoPlay();
}
showItem(index) {
// 隐藏所有项
this.items.forEach(item => item.classList.remove('active'));
this.indicators.forEach(ind => ind.classList.remove('active'));
// 显示当前项
this.items[index].classList.add('active');
this.indicators[index].classList.add('active');
}
next() {
this.currentIndex = (this.currentIndex + 1) % this.items.length;
this.showItem(this.currentIndex);
}
prev() {
this.currentIndex = (this.currentIndex - 1 + this.items.length) % this.items.length;
this.showItem(this.currentIndex);
}
bindEvents() {
this.nextBtn.addEventListener('click', () => {
this.next();
this.resetAutoPlay();
});
this.prevBtn.addEventListener('click', () => {
  this.prev();
  this.resetAutoPlay();
});

this.indicators.forEach((indicator, index) => {
  indicator.addEventListener('click', () => {
    this.currentIndex = index;
    this.showItem(index);
    this.resetAutoPlay();
  });
});

// 悬停时暂停自动播放
this.container.addEventListener('mouseenter', () => this.pauseAutoPlay());
this.container.addEventListener('mouseleave', () => this.startAutoPlay());
}
startAutoPlay() {
this.interval = setInterval(() => {
this.next();
}, this.autoPlayInterval);
}
pauseAutoPlay() {
if (this.interval) {
clearInterval(this.interval);
this.interval = null;
}
}
resetAutoPlay() {
this.pauseAutoPlay();
this.startAutoPlay();
}
}
// 初始化轮播图
new Carousel('#myCarousel');