js 轮播效果实例分享

<!--图片轮播   Start--><div class="pics-ul">  <div class="pics-ulleft">                  <ul id="allImg">      <li><img src="img/img01.png"/></li>        <li><img src="img/img2.jpg"/></li>        <li><img src="img/img1.jpg"/></li>        <li><img src="img/img3.jpg"/></li>        <li><img src="img/img4.jpg"/></li>      </ul>    <a name="btn" id="prev" class="prev" style="display: block;"></a>    <a name="btn" id="next" class="next" style="display: block;"></a>     <ul id="btn" class="pagination">     <li class="hover"><a href="#0">1</a></li>     <li><a href="#1">2</a></li>     <li><a href="#2">3</a></li>     <li><a href="#3">4</a></li>     <li><a href="#4">5</a></li>     </ul>     </div>     <div class="pics-ulright"><img src="img/imgright.png"/></div>     </div><!--图片轮播   End-->  

/*图片轮播*/var but1 = document.getElementById("prev");var abtn = document.getElementById("btn").getElementsByTagName("li"); //获取所有的按钮var lis = document.getElementById('allImg').getElementsByTagName('li');var but2 = document.getElementById("next");var index = 0;var timer = null;but2.onclick = function() {  index++;  if (index > lis.length - 1) {    index = 0;  }  setImg(index);}but1.onclick = function() {  index--;  if (index < 0) {    index = lis.length - 1;  }  setImg(index);}function changeImg() {  if (index == lis.length - 1) { //当到最后一张图片时    index = 0  } else {    index++; //图片索引发生改变  }  setImg(index);}function setImg(index) {  for (j = 0; j < lis.length; j++) {    lis[j].style.display = "none";  }  lis[index].style.display = "block";  //按钮的样式要与图片对应  for (var i = 0; i < abtn.length; i++) {    abtn[i].className = ""  }  abtn[index].className = "hover";}//自动切换timer = setInterval(changeImg, 3000);//按钮for (var i = 0; i < abtn.length; i++) {  (function() {    var p = i    abtn[p].onclick = function() {      index = p;      setImg(index);    }  })();}