轮播

作者: lacduang | 来源:发表于2019-10-12 00:23 被阅读0次

    css

    <style>
        html, body, div, ul, li {
          margin: 0;
          padding: 0;
        }
        ul, ol {
          list-style: none;
        }
        a {
          text-decoration: none;
          color: #000;
        }
        .slidshow {
          width: 600px;
          height: 300px;
          margin: 100px auto;
          overflow: hidden;
          border: 1px solid #CCC;
          position: relative;
        }
        .slidshow .slide-img-wrap {
          width: 2400px;
          position: absolute;
          left: 0;
          z-index: 1;
        }
        .slidshow .slide-img-wrap li{
          float: left;
          width: 600px;
          height: 300px;
        }
        .slidshow .slide-img-wrap li img {
          width: 600px;
          height: 300px;
        }
    
        /* 设置下一个和上一个的按钮 */
        .slidshow .slide-btn-wrap {
          position: absolute;
          z-index: 100;
          top: 50%;
          left: 0;
          width: 600px;
          height: 30px;
          margin-top: -15px;
        }
        .slidshow .slide-btn-wrap a {
          display: block;
          height: 30px;
          text-align: center;
          color: #999;
          font-size: 30px;
          line-height: 25px;
          font-weight: bold;
          background: rgba(99, 99, 99, 0.5);
          margin: 0 10px;
        }
        .slidshow .slide-btn-wrap a:hover {
          background: rgb(99, 99, 99, 0.8)
        }
        .slidshow .slide-btn-wrap .next {
          float: right;
        }
        .slidshow .slide-btn-wrap .prev {
          float: left;
        }
    
        /* 设置圆点选择 */
        .slidshow .slide-sel-btn {
          position: absolute;
          top: 90%;
          height: 10px;
          width: 64px;
          z-index: 100;
          margin-left: 268px;
        }
        .slidshow .slide-sel-btn a.on {
          background: orange;
        }
        .slidshow .slide-sel-btn a {
          width: 8px;
          height: 8px;
          margin-right: 8px;
          border-radius: 50%;
          background-color: #fff;
          float:left;
        }
      </style>
    

    html

    <body>
      <div class="slidshow">
        <!-- 滑动的图片 -->
        <ul class="slide-img-wrap">
          <li index="0" class="on"><a href="#"><img src="./img/1.jpg" alt=""></a></li>
          <li index="1"><a href="#"><img src="./img/2.jpg" alt=""></a></li>
          <li index="2"><a href="#"><img src="./img/3.jpg" alt=""></a></li>
          <li index="3"><a href="#"><img src="./img/4.jpg" alt=""></a></li>
        </ul>
    
        <!-- 上一张和下一张的按钮 -->
        <div class="slide-btn-wrap">
          <a href="javascript:;" class="prev">&lt;</a>
          <a href="javascript:;" class="next">&gt;</a>
        </div>
    
        <div class="slide-sel-btn">
          <a index="0" href="javascript:;" class="on"></a>
          <a index="1" href="javascript:;"></a>
          <a index="2" href="javascript:;"></a>
          <a index="3" href="javascript:;"></a>
        </div>
      </div>
    </body>
    

    js

    <script>
        window.onload = function() {
          let btnPrev = document.querySelector('.slide-btn-wrap .prev')
          let btnNext = document.querySelector('.slide-btn-wrap .next')
    
          btnPrev.onclick = function(e) {
            slideShowPrev()
            autoSlide()
          }
    
          btnNext.onclick = function(e) {
            slideShowNext()
            // 当再一次点击按钮时, 速度会加快 应重新调用autoSlide方法
            autoSlide()
          }
          
          // 具体选中圆圈的跳转的具体页面
          let selBtnDiv = document.querySelector('.slide-sel-btn')
          selBtnDiv.onclick = function(e) {
            e = e || window.event
            let target = e.target || e.srcElement
            if(target === this) {
              return 
            }
            // 如果是点击子元素的a标签
            let nextIndex = target.getAttribute('index')
            nextIndex = parseInt(nextIndex)
    
            // 之前设置样式类的a标签
            let curA = document.querySelector('.slide-sel-btn .on')
            let curIndex = parseInt(curA.getAttribute('index'))
            slide(curIndex, nextIndex)
            // 
            autoSlide()
          }
    
          // 实现自动滚动效果
          autoSlide()
        }
    
        // 执行上一张图片
        function slideShowPrev() {
          // 滑动下一张图片
          let curLi = document.querySelector('.slide-img-wrap .on')
          let curIndex = curLi.getAttribute('index')
          curIndex = parseInt(curIndex)
    
          let nextIndex = (curIndex -1 + 4) % 4
          slide(curIndex, nextIndex)
        }
    
        // 执行下一张图片
        function slideShowNext() {
          // 滑动下一张图片
          let curLi = document.querySelector('.slide-img-wrap .on')
          let curIndex = curLi.getAttribute('index')
          curIndex = parseInt(curIndex)
    
          // 让索引进行循环   0,1,2,3,0,1,2,3。。。
          let nextIndex = (curIndex + 1) % 4
          slide(curIndex, nextIndex)
        }
    
        var timer
        // 自动轮播
        function autoSlide() {
          // 先去掉时钟
          if(timer) {
            clearInterval(timer)
            timer = null;
          }
    
          timer = setInterval(function() {
            slideShowNext()
          }, 2000)
        }
    
    
        function slide(curIndex, nextIndex) {
          // 0 left: 0
          // 1 left: -600px;
          // 2 left: -1200px;
          // 3 left: -1800px;
          let nextLeft = nextIndex * (-600)
          // 要让下一张图片的左放到盒子的最左侧
          let imgList= document.querySelector('.slide-img-wrap')
          let curLeft = imgList.offsetLeft
    
          // 进行动画的轮播
          slideAnimation(curLeft, nextLeft, imgList, 300)
    
          // imgList.style.left = nextLeft + 'px'
    
          // 把li标签和span标签的选中的那个标签的 class 的 on 设置一下
          let liArray = document.querySelectorAll('.slide-img-wrap li')
          liArray[curIndex].className = ' '
          liArray[nextIndex].className = 'on'
    
          // slid-sel-btn 下面的 a 标签 重新设置 on
          let slideSelBtnArray = document.querySelectorAll('.slide-sel-btn a')
          slideSelBtnArray[curIndex].className = ''
          slideSelBtnArray[nextIndex].className = 'on'
        }
    
        function slideAnimation(curLeft, endLeft, element, duration) {
          let distance = endLeft - curLeft          // 总的滑动距离
          let wPerMs = distance / duration          // 没毫秒需要移动的距离
          let startTime = Date.now()
    
          let animateTimer = setInterval(function() {
            let curTime = Date.now()
            let delateTime = curTime - startTime
    
            element.style.left = (element.offsetLeft + delateTime * wPerMs) + 'px'
            duration = duration - delateTime
            if(duration <= 0){
              element.style.left = endLeft + 'px'
              clearInterval(animateTimer)
              return 
            }
            // 把当前时间设置成起始时间
            startTime = curTime
          }, 1000/60)
        }
      </script>
    

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          本文标题:轮播

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