刚学前端，最近遇到一个jQuery的问题，还请路过的大神帮忙解决下

<style type="text/css">
        * {
            margin: 0;
            padding: 0;
            text-decoration: none;
            list-style-type: none;
        }
        /*切换按钮*/
        .arrow{
            width: 50px;
            height: 50px;
            color: #000;
            font-size: 30px;
            border-radius:25px ;
            background:rgba(255,255,255,0.7);
            z-index:2;
            top: 145px;
            font-weight:bold ;
            position: absolute;
            text-align: center;
            line-height: 46px;
            display: none;
        }
        #prev{
            left: 0px;
        }
        #next{right: 0px;}
        .arrow:hover{background:rgba(255,255,255,0.3);color: #4d4f08;}
        #box:hover .arrow {display: block;}
        
        /*轮播图部分*/
        #box{
            width: 900px;
            height: 400px;
            margin: 0 auto;
            position: relative;
            border: 1px solid #ccc;
        }
        #list{
            width: 100%;
            height: 350px;
            float: left;
            /*overflow: hidden;*/
            cursor: pointer;
        }
        #list img{
            width: 900px;
            height: 100%;
            float: left;
            z-index: 1;
            margin-right: -100%;
        }
        #buttons { 
            position: absolute; 
            height: 10px; 
            width: 100%; 
            z-index: 2;
            bottom: 20px; 
            
        }
        #buttons ul{
            height: 10px; 
            width: 130px; 
            margin: 0 auto;
        }
         #buttons ul li {
             cursor: pointer; 
            float: left; 
            border: 1px solid #fff;
            width: 7px;
            height: 7px;
            border-radius: 50%; 
            background: #a4a3a3; 
            margin:3px 6px;
            }
        #buttons .on{background-color: #e42929;}
         #buttons li:hover{background-color: #e42929;}
    </style>

<div id="box">
            <div id="list">
                <img src="img/001.jpg" alt="1">
                <img src="img/002.jpg" alt="2">
                <img src="img/003.jpg" alt="3">
                <img src="img/004.jpg" alt="4">
                <img src="img/005.jpg" alt="5">
                <img src="img/006.jpg" alt="6">
            </div>
            <div id="buttons">
                <ul>
                    <li index="1" class="on"></li>
                    <li index="2"></li>
                    <li index="3"></li>
                    <li index="4"></li>
                    <li index="5"></li>
                    <li index="6"></li>
                </ul>
            </div>
            <a href="javascript:;" id="prev" class="arrow">&lt;</a>
            <a href="javascript:;" id="next" class="arrow">&gt;</a>
        </div>

$(function(){
            $("#list img:gt(0)").hide()
            $("#buttons ul li").on("click",function(){
                $(this).addClass("on").siblings().removeClass("on")
                var TheIndex=$(this).index()
                $("#list img").eq(TheIndex).fadeIn().siblings().fadeOut()
            })
            
//            $("#prev").on("click",function(){
//                
//            })
        })