var speed=20;
var d = document.getElementById("case1");
d.innerHTML = d.innerHTML+d.innerHTML;

var mymar = setInterval(marquee,speed); 
var mqe = document.getElementById("case");

mqe.onmouseover=function() {clearInterval(mymar)}
mqe.onmouseout=function() {mymar=setInterval(marquee,speed)}

function marquee(){
 
    if(d.offsetHeight/2 == mqe.scrollTop){
    
       mqe.scrollTop-=d.offsetHeight;  
      
    }
    else{
      
       mqe.scrollTop++;
       
    }
}