有人能给我解释一下这个代码的意思么??谢谢了...
</div>
<div id=demo2></div>
<script>
var t=demo.scrollTop
demo2.innerText=demo1.innerText
function qswhMarquee(){
if(demo2.offsetTop-demo.scrollTop<=0)
demo.scrollTop-=demo1.offsetHeight
else
demo.scrollTop++
}
setInterval(qswhMarquee,30)
</script>