借助marquee实现弹幕效果

<div class="right_liuyan">
     <marquee id="liuyan" scrollAmount=2 width=200 height=300 direction=up > 
         <div class="danmu">
         <p>竟然还有文字识别！！！</p>
         </div>
     <br />
     
     <div class="danmu">
         <p>这家网店的书就是好</p>
         </div>
         <br />
         
         <div class="danmu">
         <p>为啥都是计算机的书？</p>
         </div>
         <br />
     
     <div class="danmu">
         <p>还有手机版！！！！！！还有手机版！！！！！</p>
         </div>
         <br />
         
     </marquee>
     
     <input id="dan_input" type="text" value="">
     <button onclick="return addDanMu()">添加弹幕</button>
     
        
        
</div>

.danmu{
    background-color:rgb(231, 231, 231);
    border-radius:10px;
    font-size:15px;
    padding:10px 15px;
}