var speed=25

demo2.innerHTML=demo1.innerHTML

function Marquee(){

if(demo2.offsetWidth-demo.scrollLeft<=0)

 demo.scrollLeft-=demo1.offsetWidth

else{

 demo.scrollLeft++  
}  

}

var MyMar=setInterval(Marquee,speed)

demo.onmouseover=function(){clearInterval(MyMar)}

demo.onmouseout=function(){MyMar=setInterval(Marquee,speed)}