FireFox图片不能滚动

 在网上拷了一段图片无缝隙滚动的代码：   var speed=30;demo2.innerHTML=demo1.innerHTML;function Marquee(){if(demo2.offsetTop-demo.scrollTop<=0)demo.scrollTop-=demo1.offsetHeight ;else{demo.scrollTop++ ;}}var MyMar=setInterval(Marquee,speed);demo.onmouseover=function() {clearInterval(MyMar);}demo.onmouseout=function() {MyMar=setInterval(Marquee,speed);}这段代码在IE、GOOGLE浏览器下均可正常显示，但在firefox下不能滚动，于是通过firefox的错误控制台渐渐发现端倪，原来，firefox下不能直接识别demo,demo1,demo2，于是，改成document.getElementById("demo")即可。整个代码段改为：var speed=30;document.getElementById("demo2").innerHTML=document.getElementById("demo1").innerHTML;function Marquee(){if(document.getElementById("demo2").offsetTop-document.getElementById("demo").scrollTop<=0)document.getElementById("demo").scrollTop-=document.getElementById("demo1").offsetHeight;else{document.getElementById("demo").scrollTop++ ;}}var MyMar=setInterval(Marquee,speed);document.getElementById("demo").onmouseover=function() {clearInterval(MyMar);}document.getElementById("demo").onmouseout=function() {MyMar=setInterval(Marquee,speed);}这下无论哪个浏览器下都正常了。呵呵！