JSFiddle - React, Tailwind, and code Playground

HTML

<div id="focusBox" >
   <ul id="focus_pic" style="top:0;left:0;">
       <li><a target="_blank" href="#"><img src="1.jpg" width="530" height="180"></a></li>
       <li><a target="_blank" href="#"><img src="2.jpg" width="530" height="180"></a></li>
       <li><a target="_blank" href="#"><img src="3.jpg" width="530" height="180"></a></li>
       <li><a target="_blank" href="#"><img src="4.jpg" width="530" height="180"></a></li>
       <li><a target="_blank" href="#"><img src="5.jpg" width="530" height="180"></a></li>
   </ul>
 </div>

CSS

#focusBox{ width:530px; height:180px;  position:relative; margin:0 auto; zoom:1; overflow:hidden;}
    #focusBox img{border:none; margin:0;padding:0;}
    #focusBox ul { list-style:none; padding:0; margin:0; position: absolute;}
    #focusBox #focus_pic li{ height:180px; width:530px; margin:0; padding:0; float:left}
    #focusBox #focus_btn { right:5px; bottom:5px; z-index:2;}
    #focusBox #focus_btn li{ float:left;border-radius:20px; font-size:12px; width:25px; height:25px; line-height:25px; font-weight:bold; text-align:center; background:#fff; color:#000; margin-right:2px; cursor:pointer;}
    #focusBox #focus_btn li.active{ background:#f60; color:#fff;}

JavaScript

function focusBox(id,oo){
        this.$ = function(id){return document.getElementById(id)};
        this.id = id;
        this.oo = oo;//oo.v, oo.width, oo.height, oo.btnId, oo.on, oo.autoTime
        this.index = 0;
        return this.init();
    }

    focusBox.prototype = {
        init : function(){//初始化设置
            this.picLis = this.$(this.id).getElementsByTagName("li");//图片lis
            this.createBtn(this.oo.btnId);//创建数字按钮
            this.btnLis = this.$(this.oo.btnId).getElementsByTagName("li");//按钮lis
            this.oo.v==0 ? this.$(this.id).style.width = this.oo.width*this.btnLis.length + "px" : this.$(this.id).style.width = this.oo.width +"px";//判断滚动方向 修改ul的宽度
            this.btnHover();
            this.autoPlay();
        },
        autoPlay : function(){//定时器
            this.moveIndex(this.index);
            for(var i=0; i<this.btnLis.length; i++){
                this.btnLis[i].className = "";//清除按钮的样式
            }
            this.btnLis[this.index].className = "active";
        },
        moveIndex : function(index){//移动index
            clearInterval(this.autoTimer);//清楚定时
            var posx = this.oo.v==0 ? -this.index*this.oo.width : 0,
                posy = this.oo.v==1 ? -this.index*this.oo.height : 0,
                that = this;
            this.Timer = setInterval(function(){that.moveTo(posx, posy)}, 10);
        },
        moveTo : function(posx, posy){//移动坐标
            var left = parseInt(this.$(this.id).style.left),
                top = parseInt(this.$(this.id).style.top);

            left = left>posx ? left-Math.ceil((left-posx)/10) : left+Math.ceil((posx-left)/10);//当目标位置大于当前位置的时候，一次移动LEFT坐标
            top = top>posy ? top-Math.ceil((top-posy)/10) : top+Math.ceil((posy-top)/10);

            this.$(this.id).style.top = top + "px";
            this.$(this.id).style.left = left + "px";

            if(left==posx && top==posy){
                clearInterval(this.Timer);
                this.index++;
               ...