JS实现图片轮播效果实例详解【可自动和手动】

本文实例讲述了JS实现图片轮播效果。分享给大家供大家参考，具体如下：

本次轮播效果图如下：

具有以下功能：1.自动播放（鼠标进入显示区域时停止播放） 2.左右焦点切换 3.底下小按钮切换

以下为实现代码：

首先是html代码：

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>最简单的轮播效果</title>
</head>
<body>
<div class="box" id="box">
  <div class="inner">
    <!--轮播图-->
    <ul>
      <li><a href="#" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" ><img src="images/1.jpg" alt=""></a></li>
      <li><a href="#" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" ><img src="images/2.jpg" alt=""></a></li>
      <li><a href="#" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" ><img src="images/3.jpg" alt=""></a></li>
      <li><a href="#" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" ><img src="images/4.jpg" alt=""></a></li>
      <li><a href="#" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" ><img src="images/5.jpg" alt=""></a></li>
    </ul>
    <ol class="bar">
      小按钮数量无法确定，由js动态生成
    </ol>
    <!--左右焦点-->
    <div id="arr">
       <span id="left"> <</span>
       <span id="right">></span>
    </div>

  </div>
</div>

</body>
</html>

接下来是css样式：

<style>
    * {
      margin: 0;
      padding: 0
    }
    .box {
      width: 500px;
      height: 300px;
      border: 1px solid #ccc;
      margin: 100px auto;
      padding: 5px;

    }
    .inner{
      width: 500px;
      height: 300px;
      position: relative;
      overflow: hidden;
    }
    .inner img{
      width: 500px;
      height: 300px;
      vertical-align: top
    }
    ul {
      width: 1000%;
      position: absolute;
      list-style: none;
      left:0;
      top: 0;
    }
    .inner li{
      float: left;

    }

    ol {
      position: absolute;
      height: 20px;
      right: 20px;
      bottom: 20px;
      text-align: center;
      padding: 5px;
    }
    ol li{
      display: inline-block;
      width: 20px;
      height: 20px;
      line-height: 20px;
      background-color: #fff;
      margin: 5px;
      cursor: pointer;

    }
    ol .current{
      background-color: red;
    }
    #arr{
      display: none;
    }
    #arr span{
      width: 40px;
      height: 40px;
      position: absolute;
      left: 5px;
      top: 50%;
      margin-top: -20px;
      background: #fff;
      cursor: pointer;
      line-height: 40px;
      text-align: center;
      font-weight: bold;
      font-family: '黑体';
      font-size: 30px;
      color: #000;
      opacity: 0.5;
      border: 1px solid #fff;
    }
    #arr #right {
      right: 5px;
      left: auto;
    }

第三部分是最主要的js代码：

<script>
  /**
   *
   * @param id 传入元素的id
   * @returns {HTMLElement | null} 返回标签对象，方便获取元素
   */
  function my$(id) {
    return document.getElementById(id);
  }

  //获取各元素，方便操作
  var box=my$("box");
  var inner=box.children[0];
  var ulObj=inner.children[0];
  var list=ulObj.children;
  var olObj=inner.children[1];
  var arr=my$("arr");
  var imgWidth=inner.offsetWidth;
  var right=my$("right");
  var pic=0;
  //根据li个数，创建小按钮
  for(var i=0;i<list.length;i++){
    var liObj=document.createElement("li");

    olObj.appendChild(liObj);
    liObj.innerText=(i+1);
    liObj.setAttribute("index",i);

    //为按钮注册mouseover事件
    liObj.onmouseover=function () {
      //先清除所有按钮的样式

      for (var j=0;j<olObj.children.length;j++){
        olObj.children[j].removeAttribute("class");
      }
      this.className="current";
      pic=this.getAttribute("index");
      animate(ulObj,-pic*imgWidth);
    }

  }


  //设置ol中第一个li有背景颜色
  olObj.children[0].className = "current";
  //克隆一个ul中第一个li,加入到ul中的最后=====克隆
  ulObj.appendChild(ulObj.children[0].cloneNode(true));

  var timeId=setInterval(onmouseclickHandle,1000);
  //左右焦点实现点击切换图片功能
  box.onmouseover=function () {
    arr.style.display="block";
    clearInterval(timeId);
  };
  box.onmouseout=function () {
    arr.style.display="none";
    timeId=setInterval(onmouseclickHandle,1000);
  };

  right.onclick=onmouseclickHandle;
  function onmouseclickHandle() {
    //如果pic的值是5,恰巧是ul中li的个数-1的值,此时页面显示第六个图片,而用户会认为这是第一个图,
    //所以,如果用户再次点击按钮,用户应该看到第二个图片
    if (pic == list.length - 1) {
      //如何从第6个图,跳转到第一个图
      pic = 0;//先设置pic=0
      ulObj.style.left = 0 + "px";//把ul的位置还原成开始的默认位置
    }
    pic++;//立刻设置pic加1,那么此时用户就会看到第二个图片了
    animate(ulObj, -pic * imgWidth);//pic从0的值加1之后,pic的值是1,然后ul移动出去一个图片
    //如果pic==5说明,此时显示第6个图(内容是第一张图片),第一个小按钮有颜色,
    if (pic == list.length - 1) {
      //第五个按钮颜色干掉
      olObj.children[olObj.children.length - 1].className = "";
      //第一个按钮颜色设置上
      olObj.children[0].className = "current";
    } else {
      //干掉所有的小按钮的背景颜色
      for (var i = 0; i < olObj.children.length; i++) {
        olObj.children[i].removeAttribute("class");
      }
      olObj.children[pic].className = "current";
    }
  }
  left.onclick=function () {
    if (pic==0){
      pic=list.length-1;
      ulObj.style.left=-pic*imgWidth+"px";
    }
    pic--;
    animate(ulObj,-pic*imgWidth);
    for (var i = 0; i < olObj.children.length; i++) {
      olObj.children[i].removeAttribute("class");
    }
    //当前的pic索引对应的按钮设置颜色
    olObj.children[pic].className = "current";
  };

  //设置任意的一个元素,移动到指定的目标位置
  function animate(element, target) {
    clearInterval(element.timeId);
    //定时器的id值存储到对象的一个属性中
    element.timeId = setInterval(function () {
      //获取元素的当前的位置,数字类型
      var current = element.offsetLeft;
      //每次移动的距离
      var step = 10;
      step = current < target ? step : -step;
      //当前移动到位置
      current += step;
      if (Math.abs(current - target) > Math.abs(step)) {
        element.style.left = current + "px";
      } else {
        //清理定时器
        clearInterval(element.timeId);
        //直接到达目标
        element.style.left = target + "px";
      }
    }, 10);
  }
</script>

所有用图片如下：

1.jpg

2.jpg

3.jpg

4.jpg

5.jpg

下面是完整的代码：

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>最简单的轮播效果</title>
  <style>
    * {
      margin: 0;
      padding: 0
    }
    .box {
      width: 500px;
      height: 300px;
      border: 1px solid #ccc;
      margin: 100px auto;
      padding: 5px;

    }
    .inner{
      width: 500px;
      height: 300px;
      position: relative;
      overflow: hidden;
    }
    .inner img{
      width: 500px;
      height: 300px;
      vertical-align: top
    }
    ul {
      width: 1000%;
      position: absolute;
      list-style: none;
      left:0;
      top: 0;
    }
    .inner li{
      float: left;

    }

    ol {
      position: absolute;
      height: 20px;
      right: 20px;
      bottom: 20px;
      text-align: center;
      padding: 5px;
    }
    ol li{
      display: inline-block;
      width: 20px;
      height: 20px;
      line-height: 20px;
      background-color: #fff;
      margin: 5px;
      cursor: pointer;

    }
    ol .current{
      background-color: red;
    }
    #arr{
      display: none;
    }
    #arr span{
      width: 40px;
      height: 40px;
      position: absolute;
      left: 5px;
      top: 50%;
      margin-top: -20px;
      background: #fff;
      cursor: pointer;
      line-height: 40px;
      text-align: center;
      font-weight: bold;
      font-family: '黑体';
      font-size: 30px;
      color: #000;
      opacity: 0.5;
      border: 1px solid #fff;
    }
    #arr #right {
      right: 5px;
      left: auto;
    }
  </style>
</head>
<body>
<div class="box" id="box">
  <div class="inner">
    <!--轮播图-->
    <ul>
      <li><a href="#" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" ><img src="images/1.jpg" alt=""></a></li>
      <li><a href="#" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" ><img src="images/2.jpg" alt=""></a></li>
      <li><a href="#" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" ><img src="images/3.jpg" alt=""></a></li>
      <li><a href="#" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" ><img src="images/4.jpg" alt=""></a></li>
      <li><a href="#" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" ><img src="images/5.jpg" alt=""></a></li>

    </ul>

    <ol class="bar">

    </ol>
    <!--左右焦点-->
    <div id="arr">
          <span id="left">
            <
          </span>
      <span id="right">
            >
          </span>
    </div>

  </div>
</div>
<script>
  /**
   *
   * @param id 传入元素的id
   * @returns {HTMLElement | null} 返回标签对象，方便获取元素
   */
  function my$(id) {
    return document.getElementById(id);
  }

  //获取各元素，方便操作
  var box=my$("box");
  var inner=box.children[0];
  var ulObj=inner.children[0];
  var list=ulObj.children;
  var olObj=inner.children[1];
  var arr=my$("arr");
  var imgWidth=inner.offsetWidth;
  var right=my$("right");
  var pic=0;
  //根据li个数，创建小按钮
  for(var i=0;i<list.length;i++){
    var liObj=document.createElement("li");

    olObj.appendChild(liObj);
    liObj.innerText=(i+1);
    liObj.setAttribute("index",i);

    //为按钮注册mouseover事件
    liObj.onmouseover=function () {
      //先清除所有按钮的样式

      for (var j=0;j<olObj.children.length;j++){
        olObj.children[j].removeAttribute("class");
      }
      this.className="current";
      pic=this.getAttribute("index");
      animate(ulObj,-pic*imgWidth);
    }

  }


  //设置ol中第一个li有背景颜色
  olObj.children[0].className = "current";
  //克隆一个ul中第一个li,加入到ul中的最后=====克隆
  ulObj.appendChild(ulObj.children[0].cloneNode(true));

  var timeId=setInterval(onmouseclickHandle,1000);
  //左右焦点实现点击切换图片功能
  box.onmouseover=function () {
    arr.style.display="block";
    clearInterval(timeId);
  };
  box.onmouseout=function () {
    arr.style.display="none";
    timeId=setInterval(onmouseclickHandle,1000);
  };

  right.onclick=onmouseclickHandle;
  function onmouseclickHandle() {
    //如果pic的值是5,恰巧是ul中li的个数-1的值,此时页面显示第六个图片,而用户会认为这是第一个图,
    //所以,如果用户再次点击按钮,用户应该看到第二个图片
    if (pic == list.length - 1) {
      //如何从第6个图,跳转到第一个图
      pic = 0;//先设置pic=0
      ulObj.style.left = 0 + "px";//把ul的位置还原成开始的默认位置
    }
    pic++;//立刻设置pic加1,那么此时用户就会看到第二个图片了
    animate(ulObj, -pic * imgWidth);//pic从0的值加1之后,pic的值是1,然后ul移动出去一个图片
    //如果pic==5说明,此时显示第6个图(内容是第一张图片),第一个小按钮有颜色,
    if (pic == list.length - 1) {
      //第五个按钮颜色干掉
      olObj.children[olObj.children.length - 1].className = "";
      //第一个按钮颜色设置上
      olObj.children[0].className = "current";
    } else {
      //干掉所有的小按钮的背景颜色
      for (var i = 0; i < olObj.children.length; i++) {
        olObj.children[i].removeAttribute("class");
      }
      olObj.children[pic].className = "current";
    }
  }
  left.onclick=function () {
    if (pic==0){
      pic=list.length-1;
      ulObj.style.left=-pic*imgWidth+"px";
    }
    pic--;
    animate(ulObj,-pic*imgWidth);
    for (var i = 0; i < olObj.children.length; i++) {
      olObj.children[i].removeAttribute("class");
    }
    //当前的pic索引对应的按钮设置颜色
    olObj.children[pic].className = "current";
  };

  //设置任意的一个元素,移动到指定的目标位置
  function animate(element, target) {
    clearInterval(element.timeId);
    //定时器的id值存储到对象的一个属性中
    element.timeId = setInterval(function () {
      //获取元素的当前的位置,数字类型
      var current = element.offsetLeft;
      //每次移动的距离
      var step = 10;
      step = current < target ? step : -step;
      //当前移动到位置
      current += step;
      if (Math.abs(current - target) > Math.abs(step)) {
        element.style.left = current + "px";
      } else {
        //清理定时器
        clearInterval(element.timeId);
        //直接到达目标
        element.style.left = target + "px";
      }
    }, 10);
  }
</script>
</body>
</html>

希望本文所述对大家JavaScript程序设计有所帮助。