JavaScript实现0~9数字滚动抽奖效果

<html> 
 <head> 
  <title>定时器0~9抽奖系统</title> 
  <meta charset="UTF-8" /> 
  <script type="text/javascript" src="https://cdn.bootcss.com/jquery/3.2.1/jquery.min.js"></script> 
  <script type="text/javascript"> 
   $(function(){ 
    $("#start").click(function(){ 
     fn(); 
     timer = setInterval('fn()',200);//向DIV中填充内容 
    }); 
    $("#stop").click(function(){ 
     clearInterval(timer);//清除定时器 
    }); 
   }); 
   var i=0; 
   function fn(){ 
    $("#box").html(i); 
    i++; 
    if(i==10){ 
     i=0; 
    } 
   } 
  </script> 
 </head> 
 <body> 
  <div> 
   <button id="start" type="button">开始</button> 
   <button id="stop" type="button">停止</button> 
  </div> 
  <br /> 
  <div id="box" style="width:200px;height:100px;border:1px solid;line-height:100px;font-size:80px;text-align:center;"></div> 
 </body> 
</html>