var box=document.getElementById("div1"),can=true;
box.innerHTML+=box.innerHTML;
box.onmouseover=function(){can=false};
box.onmouseout=function(){can=true};
new function (){
var stop=box.scrollTop%202==0&&!can;
if(!stop)box.scrollTop==parseInt(box.scrollHeight/2)?box.scrollTop=0:box.scrollTop++;
setTimeout(arguments.callee,box.scrollTop%202?15:2800);
};