js实现淘宝首页的banner栏效果

<div class="bg clearfix">
 <div class="title">
 <a class="on" href="javascript:" >最热团购</a>
 <a href="javascript:" >商城特惠</a>
 <a href="javascript:" >名品推荐</a>
 <a href="javascript:" >缤纷活动</a>
 </div>
 <ul>
 <li class="active">
 <img class="active" src="img/1.jpg" alt="">
 <img src="img/2.jpg" alt="">
 <img src="img/3.jpg" alt="">
 <img src="img/4.jpg" alt="">
 <h3>
 <a class="hov" href="javascript:" >优惠1</a>
 <a href="javascript:" >优惠2</a>
 <a href="javascript:" >优惠3</a>
 <a href="javascript:" >优惠4</a>
 </h3>
 </li>
 <li >
 <img class="active" src="img/2.jpg" alt="">
 <img src="img/3.jpg" alt="">
 <img src="img/4.jpg" alt="">
 <img src="img/5.jpg" alt="">
 <h3>
 <a class="hov" href="javascript:" >优惠1</a>
 <a href="javascript:" >优惠2</a>
 <a href="javascript:" >优惠3</a>
 <a href="javascript:" >优惠4</a>
 </h3>
 </li>
 <li>
 <img class="active" src="img/3.jpg" alt="">
 <img src="img/4.jpg" alt="">
 <img src="img/5.jpg" alt="">
 <img src="img/6.jpg" alt="">
 <h3>
 <a class="hov" href="javascript:" >优惠1</a>
 <a href="javascript:" >优惠2</a>
 <a href="javascript:" >优惠3</a>
 <a href="javascript:" >优惠4</a>
 </h3>
 </li>
 <li >
 <img class="active" src="img/6.jpg" alt="">
 <img src="img/5.jpg" alt="">
 <img src="img/4.jpg" alt="">
 <h3>
 <a class="hov" href="javascript:" >优惠1</a>
 <a href="javascript:" >优惠2</a>
 <a href="javascript:" >优惠3</a>
 </h3>
 </li>
 </ul>
</div>

@charset "UTF-8";
body{
 font-size: 12px;
 font-family: "宋体";
}
.clearfix:after { content: "."; display: block; clear: both; height: 0; overflow: hidden; visibility: hidden; }
.clearfix{zoom: 1;}
*{
 padding: 0;
 margin: 0;
}
img{
 vertical-align: text-top;
}
ul li{
 list-style: none;
}
a{
 text-underline: none;
 text-decoration: none;
 color: #fff;
 font-weight: bold;
}
.bg{
 width: 850px;
 margin: 0 auto;
 height: 291px;
 border: 1px solid #f2f2f2;
 background: #fff;
}
.title{
 display: flex;
 flex-direction: column;
 width: 100px;
 height: 100%;
 float: left;
}
.title>a{
 width: 100%;
 display: flex;
 flex: auto;
 justify-content: center;
 align-items: center;
 background: #ccc;
 color: #000;
 font-size: 16px;
 border-bottom: 1px solid #fff;
 text-align: center;
}
.title>a:last-of-type{
 border-bottom:none ;
}
ul{
 float: left;
}
ul li{
 position: relative;
 display: none;
}
ul>li>img{
 display: none;
}
ul .active{
 display: block;
}
ul>li>h3{
 position: absolute;
 width: 100%;
 bottom: 0;
 left: 0;
 display: flex;
 
}
ul>li>h3>a{
 flex: auto;
 padding: 10px 0;
 justify-content: center;
 align-items: center;
 text-align: center;
 border-right: 1px solid #fff;
 background: cornflowerblue;
}
ul>li>h3>a:last-of-type{
 border-right: none;
}
.title .on{
 background: #fff;
}
li>h3 .hov{
 background: brown;
}

<script>
 window.οnlοad=function () {
 var oLeft=document.getElementsByClassName("title")[0];
 var oLefta=oLeft.getElementsByTagName("a");
 var oUl=document.getElementsByTagName("ul")[0];
 var oLi=oUl.getElementsByTagName("li");
 for(var i=0;i<oLefta.length;i++){
 oLefta[i].index=i;
 e(oLi[i]);
 oLefta[i].οnclick=function () {
 var That=this;
 for(var j=0;j<oLefta.length;j++){
 oLefta[j].className='';
 oLi[j].className='';
 }
 oLefta[That.index].className="on";
 oLi[That.index].className="active";
 }
 }
 function e(Li) {
 var oLia=Li.getElementsByTagName('a');
 var oImg=Li.getElementsByTagName("img");
 for(var k=0;k<oLia.length;k++){
 oLia[k].index=k;
 oLia[k].οnclick=function () {
 for(var z=0;z<oImg.length;z++){
 oImg[z].className='';
 oLia[z].className='';
 }
 oImg[this.index].className='active';
 oLia[this.index].className='hov';
 }
 
 }
 
 
 }
 }
</script>