纯js实现，完整代码如下：
<!doctype html>
<html lang="en">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<meta name="keywords" content="关键字1,关键字2" />
<meta name="Description" content="描述信息" />
<title>循环滚动</title>
<!--CSS/JS-->
<style type="text/css">
*{margin:0;padding:0;}
ul,li{list-style:none;display:block;}
#scrollBox{height:150px;width:300px;margin:100px auto;background:#f09;overflow:hidden;}
#scrollBox #con1,#con2{width:280px;float:left;}
#scrollBox li{height:15px;line-height:15px;text-align:center;} </style> </head>
<body>
<!--div-->
<div id="scrollBox">
<ul id="con1">
<li>我是测试内容1！！<li>
<li>我是测试内容2！！<li>
<li>我是测试内容3！！<li>
<li>我是测试内容4！！<li>
<li>我是测试内容5！！<li>
<li>我是测试内容6！！<li>
<li>我是测试内容7！！<li>
<li>我是测试内容8！！<li>
<li>我是测试内容9！！<li>
</ul>
<ul id="con2"></ul>
</div>
<script type="text/javascript">
var area =document.getElementById('scrollBox');
var con1 = document.getElementById('con1');
var con2 = document.getElementById('con2');
con2.innerHTML=con1.innerHTML;
function scrollUp(){
if(area.scrollTop>=con1.offsetHeight){
area.scrollTop=0;
}else{
area.scrollTop++
}
}
var time = 50;
var mytimer=setInterval(scrollUp,time);
area.onmouseover=function(){
clearInterval(mytimer);
}
area.onmouseout=function(){
mytimer=setInterval(scrollUp,time);
}
</script>
</body> </html>
预览效果请点击：我的github