基于JavaScript实现淘宝商品广告效果

ul{ margin: 0; padding: 0; }   li{ list-style: none; }    #ad{ width: 298px; height: 208px; border: 1px #ff6300 solid; padding: 4px 1px; text-align: center; }   #ad .listL{ float: left; }   #ad .listR{ float: right; }   #ad li{ width: 48px; height: 26px; border: 1px #ffadad solid; background: #fff7f7; color: #333; line-height: 26px; margin-bottom: 2px; cursor: pointer; }   #ad img{ height: 206px; width: 188px; background: url(images/loader_ico.gif) no-repeat center center; }   #ad .cur{ background: #ff8494; color: #fff } 

<div id="ad">   <ul class="listL">    <!-- <li class="cur"></li>    <li></li>    <li></li>    <li></li>    <li></li>    <li></li>    <li></li> -->   </ul>   <a href="#"><img src="" alt=""></a>   <ul class="listR">    <!-- <li></li>    <li></li>    <li></li>    <li></li>    <li></li>    <li></li>    <li></li> -->   </ul>  </div> 

window.onload = function(){   var oDiv = document.getElementById('ad');   var aUl = oDiv.getElementsByTagName('ul');   var oImg = oDiv.getElementsByTagName('img')[0];   var aImg = ['images/pic1.jpg','images/pic2.jpg','images/pic3.jpg','images/pic4.jpg','images/pic5.png','images/pic6.png','images/pic7.png','images/pic8.png','images/pic1.jpg','images/pic2.jpg','images/pic3.jpg','images/pic4.jpg','images/pic5.png','images/pic6.png'];   var aTxt = ['连衣裙','T恤','雪纺','铅笔裤','婚纱','外套','连体裤','包包','凉鞋','单鞋','太阳镜','丝袜','帆布鞋','情侣鞋'];   var len = aImg.length;   var oldNum = 0;   var num = 0;   var timer = null;   var speed = 1;    // 创建添加左右两侧li   for( var i = 0; i < len/2; i++){    aUl[0].innerHTML += '<li>'+ aTxt[i] +'</li>'    aUl[1].innerHTML += '<li>'+ aTxt[i + len/2] +'</li>'   }    var aLiL = aUl[0].getElementsByTagName('li');   var aLiR = aUl[1].getElementsByTagName('li');   var arrLi = [];   // 将遍历的所有li添加到数组arrLi中   for( var i = 0; i < aLiL.length; i++){    arrLi.push(aLiL[i]);   }   for( var i = 0; i < aLiR.length; i++){    arrLi.push(aLiR[i]);   }   // console.log(arrLi.length);    // 函数初始化   function init(n){    oImg.src = aImg[n];    arrLi[oldNum].className = '';    arrLi[n].className = 'cur';    oldNum = n;   }   init(0);    // 鼠标经过li，图片切换   for(var i = 0; i < len; i++){    arrLi[i].index = i;    arrLi[i].onmouseover = function(){     init(this.index);    }   };    // 定时切换   function fnTimer(n){    timer = setInterval(function(){          // type1:顺序切换     /* n ++;     if(n == len){      n = 0;     }*/      // type2：倒序切换     if(n == len-1){      speed = -1;     }else if(n== 0){      speed = 1;     }     n += speed;     init(n);    },1000);   };   fnTimer(0);    // 鼠标移入，清除定时器   oDiv.onmouseover = function(){    clearInterval(timer);   };    // 鼠标移出，开启定时器   oDiv.onmouseout = function(){    fnTimer(oldNum);   };   };