// Lower is faster 
var scrollSpeed = 60;

function controlScrollUp() {
	scrollingDirection = 'UP';
	stopAllScroller();
	scrollUp();
}
function controlScrollDown() {
	scrollingDirection = 'DOWN';
	stopAllScroller();
	scrollDown();
}

function scrollUp() {
	if(iens6&&parseInt(oContent.style.top)>=(contentHeight*(-1)+100)){
		oContent.style.top=parseInt(oContent.style.top)-step;
	}else if(ns4&&oContent.top>=(contentHeight*(-1)+100)){
		oContent.top-=step;
	} else {
		shiftToUp();
	}  
	scrollTimerUp = setTimeout("scrollUp()",scrollSpeed);	
	
}

function scrollDown() {
	if(iens6&&parseInt(oContent.style.top)<=0){
		oContent.style.top=parseInt(oContent.style.top)+step;
	}else if(ns4&&oContent.top<=0){ 
		oContent.top+=step;
	} else {
		shiftToDown();
	}  
	scrollTimerDown = setTimeout("scrollDown()",scrollSpeed);	
}
<!-- function to stop all scroll timers -->
function stopAllScroller() {
	if(window.scrollTimerUp){
		clearTimeout(scrollTimerUp);
	}
	if(window.scrollTimerDown){
		clearTimeout(scrollTimerDown);
	}
}

function playScroller() {
	if(scrollingDirection=="UP"){
		controlScrollUp();
	} else if (scrollingDirection=="DOWN") {
		controlScrollDown();
	} else {
		controlScrollUp();
	}
}

function shiftToUp(){
	stopAllScroller();
	if (iens6) {
		oContent.style.top=0;
	}else{
		oContent.top=0;
	}
}
function shiftToDown(){
	stopAllScroller();
	if (iens6) {
		oContent.style.top=-(contentHeight-100);
	} else {
		oContent.top=-(contentHeight-100);
	}
}

function getContentHeight(){
	if (iens6) {
		contentHeight = oContent.offsetHeight ;
		contentHeight = contentHeight==0 ? 1630 : contentHeight;

	}
}
window.onLoad=getContentHeight();
window.onLoad=controlScrollUp();