var Parent = document.getElementById("Parent");
    var ChildA = document.getElementById("Child_A");
    var parentWidth = 888;
    var count=2; 
    ChildA.innerHTML = ChildA.innerHTML + " " + ChildA.innerHTML;
    while (Parent.scrollWidth<=parentWidth)
    {    
        count *=2;
        ChildA.innerHTML = ChildA.innerHTML + " " + ChildA.innerHTML;
      
    }
    
var speed=30;

function Marquee()
{
    
    if (ChildA.offsetWidth/count-Parent.scrollLeft<0)//NB calculate the optimal position
    {
        Parent.scrollLeft -= ChildA.offsetWidth/count;
    }
    else
    {
    		
        Parent.scrollLeft++ ;
        
    }
   
}
var MyMar=setInterval(Marquee,speed)
Parent.onmouseover=function() {clearInterval(MyMar)}
Parent.onmouseout=function() {MyMar=setInterval(Marquee,speed)}