window.onload=function(){
function toDou(n){
return n<10?"0"+n:""+n;
}
var oImg=document.getElementsByTagName("img");
setInterval(clock,1000);
clock()
function clock(){
var oDate=new Date();
var oH=oDate.getHours();
var oF=oDate.getMinutes();
var oM=oDate.getSeconds();
var str=toDou(oH)+toDou(oF)+toDou(oM);
for(var i=0;i<oImg.length;i++){
move(oImg[i],{"marginTop":-35*str.charAt(i)});
}
}
}

<ul>
<li><img src="img/num.png" alt="javascript很炫的数字时钟滚动效果" /></li>
<li><img src="img/num.png" alt="javascript很炫的数字时钟滚动效果" /></li>
<li>:</li>
<li><img src="img/num.png" alt="javascript很炫的数字时钟滚动效果" /></li>
<li><img src="img/num.png" alt="javascript很炫的数字时钟滚动效果" /></li>
<li>:</li>
<li><img src="img/num.png" alt="javascript很炫的数字时钟滚动效果" /></li>
<li><img src="img/num.png" alt="javascript很炫的数字时钟滚动效果" /></li>
</ul>
*{ padding:0; margin:0; list-style:none;}
ul{width:200px; margin: 100px auto;}
li{ float:left; height:35px; overflow:hidden; line-height:35px;}