Continuous loop scroll up code

<div align= "Center" id= "demo" style= "overflow:hidden;height:200px;width:250px;border:1px solid #6699cc; Font-size:14px;color: #336699 line-height:22px;text-align:left;padding:10px "
    <div ID = "Demo1"
        seamless upward scrolling, compatible with IE and ff<br/>
  computer hardware and software application network <BR/
  Web site: http://www.45it.com<br/>
        focus on computer learning
     </div>
    <div id= "Demo2" ></DIV>
</div>
<script language= "JavaScript" type= "Text/javascript"
<!--
var demo = document.getElementById ("demo");
Var Demo1 = document.getElementById ("Demo1");
var Demo2 = document.getElementById ("Demo2");
Var speed=30;   //scrolling speed value, the greater the value the slower
Var nnn=200/demo1.offsetheight
for (i=0;i<nnn;i++) { demo1.innerhtml+= "<br/>" + demo1.innerhtml}
demo2.innerhtml = demo1.innerhtml   //GLong Demo2 is demo1
function Marquee () {
    if (demo2.offsettop-demo.scrolltop<=0)     //When scrolling to the junction of Demo1 and Demo2
        demo.scrolltop-=demo1.offsetheight    //demo jump to the top
    else{
        demo.scrolltop++    //If horizontal, change all height top to width left
   }
}
var my Mar = SetInterval (marquee,speed);       //Set timer
Demo.onmouseover = function ( {clearinterval (MyMar)}   ///mouse over to clear the timer to achieve the purpose of scrolling stop
Demo.onmouseout = function () {MyMar = SetInterval (Marquee,speed)}    //Reset timer when mouse is moved
;
</script>