                        課程
                    
                        /前端開發(fā)
                        
                            /JavaScript
                        
                        /信息滾動效果制作

我的代碼怎么運行處BUG了，滾動不到最后就又開始滾動了而且還越滾越快？

<!DOCTYPE?html>
<html>
<head>
<meta?charset="UTF-8">
<title>Document</title>
<style?type="text/css">
????????body?{
font-size:?12px;
line-height:?24px;
text-algin:?center;????????/*?頁面內(nèi)容居中?*/
}
*?{
margin:?0px;
padding:?0px;????????????/*??去掉所有標簽的marign和padding的值??*/
}
????????#box{
?????????width:410px;
?????????height:?230px;
?????????margin:?0?auto;
??????????margin-top:?50px;
??????????border:?5px?solid?gray;
??????????border-radius:?10px;
??????????overflow:?hidden;
????????}
????????#box?h3{
?????????background:?red;
?????????height:?65px;
?????????line-height:?65px;;
?????????color:?white;
?????????font-size:25px;
?????????padding:10px;
?????????padding-left:?20px;
?????????margin-top:0;
????????}
????????#box?h3?a{
?????????font-size:?10px;
?????????text-decoration:?none;
?????????float:?right;
?????????color:?white;
????????}
????????#moocBox{
?????????width:?410px;
?????????height:?150px;
?????????margin-top:?5px;
?????????overflow:?hidden;?????
????????}
????????#moocBox?ul{
????????????list-style-type:?none;
????????????padding:?0?40px;
????????}
????????#moocBox?ul?li{
?????????margin-top:?5px;
?????????height:?24px;
????????}
????????#moocBox?ul?li?a{
?????????text-decoration:?none;
?????????color:black;
?????????font-size:?12px;
????????}
????????#moocBox?ul?li?a:hover{
?????????color:red;
????????}
????????#moocBox?ul?span{
?????????color:?gray;
?????????float:?right;
????????}
</style>??
</head>
<body>
<div?id="box">
???????<h3>最新課程?<a?href="#">更多》》</a></h3>
<div?id="moocBox">
<ul?id="cn1">
<li><a?href="#">1.學會html5?絕對的屌絲逆襲（案例）</a><span>2013-09-18</span></li>
???????<li><a?href="#">2.tab頁面切換效果（案例）</a><span>2013-10-09</span></li>
???????<li><a?href="#">3.圓角水晶按鈕制作（案例）</a><span>2013-10-21</span></li>
???????<li><a?href="#">4.HTML+CSS基礎課程(系列)</a><span>2013-11-01</span></li>
???????<li><a?href="#">5.分頁頁碼制作（案例）</a><span>2013-11-06</span></li>
???????<li><a?href="#">6.導航條菜單的制作（案例）</a><span>2013-11-08</span></li>
???????<li><a?href="#">7.信息列表制作(案例)</a><span>2013-11-15</span></li>
???????<li><a?href="#">8.下拉菜單制作(案例)</a><span>2013-11-22</span></li>
???????<li><a?href="#">9.如何實現(xiàn)“新手引導”效果</a><span>2013-12-06</span></li>
</ul>
</div>
</div>
</body>
????<script?type="text/javascript">
?????var?box=document.getElementById("moocBox");
?????box.innerHTML+=box.innerHTML;
?????var?iHegiht=24;
?????function?startMove(){
?????box.scrollTop++;
?????time=setInterval("scrollUp()",50)
?????}
?????function?scrollUp(){
?????box.scrollTop++;
?????if(box.scrollTop?%?iHegiht==0){
?????clearInterval(time);
?????setTimeout("startMove()",2000)
?????}else{
?????box.scrollTop++;
?????if?(box.scrollTop>=box.offsetHeight/2)?{
?????box.scrollTop=0;
?????}
?????}
?????}
?????setTimeout("startMove()",2000);//初始化
????</script>
</html>