html樣式

<div class='box'>
  <ul id="imgul">                      //把圖片按順序放入盒子
    <li><img src="./imgs/1.jpg" alt=""></li>
    <li><img src="./imgs/2.jpg" alt=""></li>
    <li><img src="./imgs/3.jpg" alt=""></li>
    <li><img src="./imgs/4.jpg" alt=""></li>
    <li><img src="./imgs/5.jpg" alt=""></li>
  </ul>
  <span id="left">
    < </span> <span id="right"> >                 //左右倆邊的小按鈕
  </span>    
  <ol>                                            //小按鈕
    <li>1</li>
    <li>2</li>
    <li>3</li>
    <li>4</li>
    <li>5</li>
  </ol>
</div>

css樣式

* {
  margin: 0;
  padding: 0;
  list-style: none;
}   //清除默認(rèn)y樣式

.box {
  position: relative;
  width: 600px;
  height: 370px;
  margin: 50px auto;
  overflow: hidden;
}     //給盒子寬高，然后給圖片溢出隱藏

.box #imgul {
  width: 600px;
  height: 370px;
}

.box #imgul li {
  width: 600px;
  height: 370px;
}

.box #imgul li img {
  width: 600px;
  height: 370px;
  display: block;
  float: left;
}

.box span {
  position: absolute;
  top: 50%;
  margin-top: -30px;
  width: 30px;
  height: 60px;
  background-color: rgba(0, 0, 0, 0.6);
  color: #fff;
  font-size: 40px;
}

.box #left {
  left: 0px;
}

.box #right {
  right: 0px;
}

.box ol {
  position: absolute;
  bottom: 20px;
  left: 30px;
}

.box ol li {
  width: 20px;
  height: 20px;
  background: yellow;
  font-size: 15px;
  line-height: 20px;
  float: left;
  margin: 0px 3px;
  text-align: center;
}

.box ol .active {
  background: #fff;
  color: red;
}

js樣式

 function $(names) {
      return document.getElementById(names);
    }
    var left = $('left'); //左按鈕
    var right = $('right'); //右按鈕
    var box = document.getElementsByClassName('box')[0];
    var li_list = document.querySelectorAll('#imgul li'); //獲取圖片的li
    var ol_list = document.querySelectorAll('ol li');
    var timer = null; //聲明定時(shí)器
    var count = 0;

    function auto() { //執(zhí)行自動(dòng)輪播
      count++;
      if (count > li_list.length - 1) {
        count = 0;
      }
      for (var i = 0; i < li_list.length; i++) {
        li_list[i].style = 'display:none;';
        ol_list[i].className = '';
      }
      li_list[count].style = 'display:block;'
      ol_list[count].className = 'active';

    }
    timer = setInterval(auto, 500); //調(diào)用定時(shí)器

    // 點(diǎn)擊右側(cè)，切換下一個(gè)
    right.onclick = function () {
      auto();
    }
    // 點(diǎn)擊左側(cè)，切換上一個(gè)
    left.onclick = function () {
      count--;
      if (count < 0) {
        count = li_list.length - 1;
      }
      console.log(count);
      for (var i = 0; i < li_list.length; i++) {
        li_list[i].style = 'display:none;';
        ol_list[count].className = '';
      }
      li_list[count].style = 'display:block;';
      ol_list[count].className = 'active';
    }

    box.onmouseover = function () { //鼠標(biāo)劃上去，停止輪播
      clearInterval(timer);
    }
    box.onmouseout = function () { //鼠標(biāo)劃出，繼續(xù)輪播
      timer = setInterval(auto, 500); //調(diào)用定時(shí)器
    }


    //點(diǎn)擊小按鈕，切換圖片
    for (var j = 0; j < ol_list.length; j++) {
      ol_list[j].ind = j; //為每個(gè)小按鈕添加下標(biāo)
      ol_list[j].onclick = function () { //進(jìn)入點(diǎn)擊事件
        for (var i = 0; i < li_list.length; i++) { //干掉所有人
          li_list[i].style = 'display:none;';
          ol_list[i].className = '';
        }
        li_list[this.ind].style = 'display:block;'; //留下我自己
        ol_list[this.ind].className = 'active'; //留下我自己
        count = this.ind; // 把當(dāng)前的角標(biāo)值賦值給count 希望他從當(dāng)前再開始
      }
    }