学习技巧：JS不间断向下滚动

tznktg

<div id=demo style=overflow:hidden;height:300;width:500;background:#f4f4f4;color:#ffffff><div id=demo1>
<img src="http://www.geekg.com/files/images8/20070722233532H.jpg">
<img src="http://www.geekg.com/files/images6/20070718000229n.jpg">
<img src="http://www.geekg.com/files/images8/20070724004138e.jpg">
<img src="http://www.geekg.com/files/images8/200707240019131.jpg">
<img src="http://www.geekg.com/files/images8/20070722234005h.jpg">
  </div>
  <div id=demo2></div>
  </div>
    <script>
    var speed=30
    demo2.innerHTML=demo1.innerHTML
    demo.scrollTop=demo.scrollHeight
    function Marquee(){
    if(demo1.offsetTop-demo.scrollTop>=0)
    demo.scrollTop+=demo2.offsetHeight
    else{
    demo.scrollTop--
    }
    }
    var MyMar=setInterval(Marquee,speed)
    demo.onmouseover=function() {clearInterval(MyMar)}
    demo.onmouseout=function() {MyMar=setInterval(Marquee,speed)}
    </script>