var ScrollTimer = null;
var ScrollPause = 30;
var ScrollStep = 5;

function Scroll(_id,_direction){
var Navigation = document.getElementById(_id);

switch(_direction){
case "left":
Navigation.scrollLeft = (Navigation.scrollLeft < 0) ? 0 : Navigation.scrollLeft - ScrollStep;
break ;
case "right":
Navigation.scrollLeft = Navigation.scrollLeft + ScrollStep;
break ;
case "up":
Navigation.scrollTop = (Navigation.scrollTop < 0) ? 0 : Navigation.scrollTop - ScrollStep;
break ;
case "down":
Navigation.scrollTop = Navigation.scrollTop + ScrollStep;
break ;
 }
}

function StartScroll(_id,_direction){
 ScrollTimer = setInterval("Scroll('" + _id + "','" + _direction + "')", ScrollPause);
}

function StopScroll(){
 clearInterval(ScrollTimer);
}