web前端利用jq实现折叠菜单

{
            margin: 0px;
            padding: 0;
        }
        .nav{
            list-style: none;
            width: 300px;
            margin: 100px auto;
            background: #ffb2a7;
        }
        .nav>li{
            border: 1px solid #000000;
            line-height: 35px;
            border-bottom: none;
            position:relative;
            text-align: center;
        }
        .nav>li:last-child{
            border-bottom: 1px solid #000000;
            border-bottom-right-radius: 10px;
            border-bottom-left-radius: 10px;
        }
        .nav>li:first-child{
            border-top-right-radius: 10px;
            border-top-left-radius: 10px;
        }
        .nav>li>ul{
            list-style: none;
            background: #f8615a;
            display: none;
        }
        .nav>li>ul>li{
            border-top: 1px solid #ffb2a7;
            line-height: 35px;
        }
        .nav>li>ul>li:hover{
            background: #b80d57;
        }
        .nav>li>span{
            background:url("./img/下拉前.png") no-repeat center center;
           display: inline-block;
            width: 32px;
            height: 32px;
            position:absolute;
            right: 10px;
            top: 5px;
        }
    
    {
                $(".nav>li").click(function(){
                    var $sub =$(this).children(".sub");
                    $sub.slideDown(1000);
                    var otherSub=$(this).siblings().children(".sub");
                    otherSub.slideUp(1000);
                })
            });
            


    

一级菜单一
            

二级菜单
                
二级菜单
            

        
一级菜单二
            

二级菜单
                
二级菜单
            

        
一级菜单三
            

二级菜单
                
二级菜单
            

        
一级菜单四
            

二级菜单
                
二级菜单