var speed_top=50; //数字越大速度越慢
var tab_top=document.getElementById("demo_top");
var tab1_top=document.getElementById("demo_top1");
var tab2_top=document.getElementById("demo_top2");
tab2_top.innerHTML=tab1_top.innerHTML; //克隆demo_top1为demo_top2
function Marquee_top(){
if(tab2_top.offsetTop-tab_top.scrollTop<=0)//当滚动至demo_top1与demo_top2交界时
tab_top.scrollTop-=tab1_top.offsetHeight //demo_top跳到最顶端
else{
tab_top.scrollTop++
}
}
var MyMar_top=setInterval(Marquee_top,speed_top);
tab_top.onmouseover=function() {clearInterval(MyMar_top)};//鼠标移上时清除定时器达到滚动停止的目的
tab_top.onmouseout=function() {MyMar_top=setInterval(Marquee_top,speed_top)};//鼠标移开时重设定时器