var scrolling;
function startScroll(id, dir) {  
	var speed = 0;  
	if (dir == 'up') {    
	speed = -3;  
} else if(dir == 'down') {    
	speed = 3;  
}  
	performScroll(id, speed);
}
function performScroll(id, speed) {  
	var el = document.getElementById(id);  
	el.scrollTop += speed;  
	scrolling = setTimeout("performScroll('" + id + "', " + speed + ")", 20);
}
function stopScroll() {  
	clearTimeout(scrolling);
}