JavaScript實現無縫輪播圖的示例代碼

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花費一個下午從0到1實現的輪播圖，當然還有很多需要改進的地方（歡迎提出需要改進的地方），等我再努力努力，將其封裝成一個組件。

上效果

一、實現過程

1）首先實現基本佈局

 <div class="carousel-container">
    //圖片列表
    <div class="carousel-list"></div>
    //上一張
    <div class="carousel-arrow carousel-arrow-left">&lt</div>
    //下一張
    <div class="carousel-arrow carousel-arrow-right">&gt</div>
    //導航點
    <div class="indicator">
      <span class="active"></span>
      <span></span>
      <span></span>
    </div>
  </div>

2）主要樣式

簡單佈局樣式就不說瞭，主要講如何將圖片橫向排列起來

先給容器設置相對定位，通過overflow將超出部分隱藏

.carousel-container {
      position: relative;
      width: 500px;
      height: 300px;
      /* overflow: hidden; */
      background-color: #ccc;
 }

然後圖片列表設置相對定位和flex盒子，這樣每一個滑塊就橫向排列成一排瞭

.carousel-container .carousel-list {
      position: relative;
      display: flex;
      height: 100%;
      width: 100%;
 }

左右滑動按鈕通過絕對定位+transform的方式移動到兩邊，導航點也是一樣，就不一一詳說瞭

二、如何實現無縫呢 （重點來瞭）

思路：

1、先實現向後滾動無縫連接，將最後一張復制一份放到最前面，當滾動到最後一張時，再次滾動，將要滾動到第一張時，先取消過渡transition，瞬間跳到最前面復制的那張上，然後繼續運行動畫到第一張，這樣看起來就無縫瞭

2、向前滾動無縫連接，思路同上，復制第一張圖片放到最後，當滾動到第一張，再次滾動時，瞬間跳到最後復制的那張圖片上，繼續滾動到輪播圖的最後一張上。

主要代碼

先獲取到dom元素，currentIndex是當前輪播到的圖片下標

let currentIndex = 0;
const doms = {
      carouselList: document.querySelector('.carousel-list'),
      arrowLeft: document.querySelector('.carousel-arrow-left'),
      arrowRight: document.querySelector('.carousel-arrow-right'),
      indicator: document.querySelectorAll('.indicator span')
    }

先初始化dom，復制圖片

// 復制第一張放最後，最後一張圖片放第一張之前
    function init() {
      let lastImg = doms.carouselList.lastElementChild.cloneNode(true)
      let firstImg = doms.carouselList.firstElementChild.cloneNode(true)

      doms.carouselList.appendChild(firstImg)
      doms.carouselList.insertBefore(lastImg, doms.carouselList.firstElementChild)
      lastImg.style.position = 'absolute'
      lastImg.style.transform = 'translateX(-100%)'
    }
    //執行一下
    init()

實現到任意一張圖片的方法

function moveTo(index) {
      doms.carouselList.style.transform = `translateX(-${index * 100}%)`
      doms.carouselList.style.transition = '.5s'

      // 去掉導航點選中效果
      let active = document.querySelector('.indicator span.active')
      active.classList.remove('active')
      // 添加選中效果
      doms.indicator[index].classList.add('active')
      currentIndex = index
    }

給導航點綁定點擊跳轉事件

// 給導航點添加事件
    doms.indicator.forEach((item, i) => {
      item.onclick = function () {
        moveTo(i);
      }
    })

給前後按鈕綁上執行事件,判斷邊界圖片，及時取消過渡效果，瞬間跳到復制的圖片位置，調用moveTo到第一張或最後一張圖片上。

let indicatorLength = doms.indicator.length;
    function preSlide() {
      if (currentIndex === 0) {
        doms.carouselList.style.transition = 'none'
        doms.carouselList.style.transform = `translateX(-${indicatorLength * 100}%)`
        doms.carouselList.clientHeight
        moveTo(indicatorLength - 1)
      } else {
        moveTo(currentIndex - 1)
      }
    }
    function nextSlide() {
      if (currentIndex === doms.indicator.length - 1) {
        doms.carouselList.style.transition = 'none'
        doms.carouselList.style.transform = 'translateX(100%)'
        doms.carouselList.clientHeight
        moveTo(0)
      } else {
        moveTo(currentIndex + 1)
      }
    }

    doms.arrowLeft.onclick = function () {
      preSlide();
    }

    doms.arrowRight.onclick = function () {
      nextSlide()
    }

最後使用定時器調用nertSlide方法就實現自動播放瞭

function start(time = 2000) {
      setInterval(() => {
        nextSlide()
      }, time)
    }
    start()

完整代碼

<!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>
  <style>
    * {
      margin: 0;
      padding: 0;
      box-sizing: border-box;
    }

    .carousel-container {
      margin: 0 auto;
      position: relative;
      width: 500px;
      height: 300px;
      /* overflow: hidden; */
      background-color: #ccc;
    }

    .carousel-container .carousel-list {
      position: relative;
      display: flex;
      height: 100%;
      width: 100%;
    }

    .carousel-container .carousel-list .slide {
      flex: 0 0 100%;
      height: 100%;
      width: 100%;
    }

    .slide a {
      display: flex;
      justify-content: center;
      align-items: center;
      height: 100%;
      width: 100%;
    }

    .slide a img {
      width: 100%;
    }

    .carousel-container .carousel-arrow {
      display: none;
      position: absolute;
      width: 36px;
      height: 36px;
      border-radius: 50%;
      color: white;
      text-align: center;
      line-height: 36px;
      cursor: pointer;

      background-color: rgba(31, 45, 61, .2);
    }

    .carousel-container:hover .carousel-arrow {
      display: block;
    }

    .carousel-container:hover .carousel-arrow:hover {
      background-color: rgba(31, 45, 61, .4);
    }

    .carousel-container .carousel-arrow-left {
      top: 50%;
      left: 2%;
      transform: translateY(-50%);
    }

    .carousel-container .carousel-arrow-right {
      top: 50%;
      right: 2%;
      transform: translateY(-50%);
    }

    .carousel-container .indicator {
      display: flex;
      position: absolute;
      left: 50%;
      top: 90%;
      transform: translateX(-50%)
    }

    .carousel-container .indicator span {
      margin: 2px 5px;
      padding: 3px;
      width: 5px;
      height: 5px;
      border: 1px solid white;
      border-radius: 5px;
    }

    .active {
      background-color: #fff;
    }
  </style>
</head>


<body>
  <div class="carousel-container">
    <div class="carousel-list">
      <div class="slide">
        <a href="">
          <img
            src="https://ts4.cn.mm.bing.net/th?id=OIP-C.kB-Ovasi0GW67-rmwnAcwAHaEo&w=316&h=197&c=8&rs=1&qlt=90&o=6&dpr=1.25&pid=3.1&rm=2">
        </a>
      </div>
      <div class="slide">
        <a href="">
          <img
            src="https://ts1.cn.mm.bing.net/th?id=OIP-C.QPH1IBosDYBqaU3O6wV3YAHaEo&w=316&h=197&c=8&rs=1&qlt=90&o=6&dpr=1.25&pid=3.1&rm=2"></a>
      </div>
      <div class="slide">
        <a href="">
          <img
            src="https://ts2.cn.mm.bing.net/th?id=OIP-C.P3NSGTdAYdyqy5zJpb5QXQHaEo&w=316&h=197&c=8&rs=1&qlt=90&o=6&dpr=1.25&pid=3.1&rm=2"
            alt=""></a>
      </div>
    </div>
    <div class="carousel-arrow carousel-arrow-left">&lt</div>
    <div class="carousel-arrow carousel-arrow-right">&gt</div>
    <div class="indicator">
      <span class="active"></span>
      <span></span>
      <span></span>
    </div>
  </div>
</body>

<script>
  window.onload = function () {
    const doms = {
      carouselList: document.querySelector('.carousel-list'),
      arrowLeft: document.querySelector('.carousel-arrow-left'),
      arrowRight: document.querySelector('.carousel-arrow-right'),
      indicator: document.querySelectorAll('.indicator span')
    }
    let currentIndex = 0;

    function moveTo(index) {
      doms.carouselList.style.transform = `translateX(-${index * 100}%)`
      doms.carouselList.style.transition = '.5s'

      // 去掉導航點選中效果
      let active = document.querySelector('.indicator span.active')
      active.classList.remove('active')
      // 添加選中效果
      doms.indicator[index].classList.add('active')
      currentIndex = index
    }

    // 給導航點添加事件
    doms.indicator.forEach((item, i) => {
      item.onclick = function () {
        moveTo(i);
      }
    })
    // 復制第一張放最後，最後一張圖片放第一張之前
    function init() {
      let lastImg = doms.carouselList.lastElementChild.cloneNode(true)
      let firstImg = doms.carouselList.firstElementChild.cloneNode(true)

      doms.carouselList.appendChild(firstImg)
      doms.carouselList.insertBefore(lastImg, doms.carouselList.firstElementChild)
      lastImg.style.position = 'absolute'
      lastImg.style.transform = 'translateX(-100%)'
    }

    let indicatorLength = doms.indicator.length;
    function preSlide() {
      if (currentIndex === 0) {
        doms.carouselList.style.transition = 'none'
        doms.carouselList.style.transform = `translateX(-${indicatorLength * 100}%)`
        doms.carouselList.clientHeight
        moveTo(indicatorLength - 1)
      } else {
        moveTo(currentIndex - 1)
      }
    }
    function nextSlide() {
      if (currentIndex === doms.indicator.length - 1) {
        doms.carouselList.style.transition = 'none'
        doms.carouselList.style.transform = 'translateX(100%)'
        doms.carouselList.clientHeight
        moveTo(0)
      } else {
        moveTo(currentIndex + 1)
      }
    }

    doms.arrowLeft.onclick = function () {
      preSlide();
    }

    doms.arrowRight.onclick = function () {
      nextSlide()
    }

    function start(time = 2000) {
      setInterval(() => {
        nextSlide()
      }, time)
    }
    start()
    init()

  }
</script>

</html>

到此這篇關於JavaScript實現無縫輪播圖的示例代碼的文章就介紹到這瞭,更多相關JavaScript無縫輪播圖內容請搜索WalkonNet以前的文章或繼續瀏覽下面的相關文章希望大傢以後多多支持WalkonNet！

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