var scrollRate = 4;
function scrollDown(div_name){
	var obj = document.getElementById(div_name);
	if(!obj.style.top) obj.style.top = "0px";
	obj.style.top = (parseInt(obj.style.top) - scrollRate) + "px";
}

function scrollUp(div_name){
	var obj = document.getElementById(div_name);
	if(!obj.style.top) obj.style.top = "0px";
	obj.style.top = (parseInt(obj.style.top) + scrollRate) + "px";
}

function scrollRight(div_name){
	var obj = document.getElementById(div_name);
	if(!obj.style.left) obj.style.left = "0px";
	obj.style.left = (parseInt(obj.style.left) - scrollRate) + "px";
}

function scrollLeft(div_name){
	var obj = document.getElementById(div_name);
	if(!obj.style.left) obj.style.left = "0px";
	obj.style.left = (parseInt(obj.style.left) + scrollRate) + "px";
}

function scrollDownBy(div_name, rate){
	var obj = document.getElementById(div_name);
	if(!obj.style.top) obj.style.top = "0px";
	obj.style.top = (parseInt(obj.style.top) - rate) + "px";
}

function scrollUpBy(div_name, rate){
	var obj = document.getElementById(div_name);
	if(!obj.style.top) obj.style.top = "0px";
	obj.style.top = (parseInt(obj.style.top) + rate) + "px";
}

function scrollRightBy(div_name, rate){
	var obj = document.getElementById(div_name);
	if(!obj.style.left) obj.style.left = "0px";
	obj.style.left = (parseInt(obj.style.left) - rate) + "px";
}

function scrollLeftBy(div_name, rate){
	var obj = document.getElementById(div_name);
	if(!obj.style.left) obj.style.left = "0px";
	obj.style.left = (parseInt(obj.style.left) + rate) + "px";
}

var scroll_updown_id = 0;
var scroll_leftright_id = 0;

function start_scrollUp(div_name){
	stop_scrollUpDown();
	scroll_updown_id = window.setInterval("scrollUp('"+div_name+"')",50);
}

function start_scrollDown(div_name){
	stop_scrollUpDown();
	scroll_updown_id = window.setInterval("scrollDown('"+div_name+"')",50);
}

function stop_scrollUpDown(){
	if(scroll_updown_id){
		window.clearInterval(scroll_updown_id);
		scroll_updown_id = 0;
	}
}

function start_scrollLeft(div_name){
	stop_scrollLeftRight();
	scroll_leftright_id = window.setInterval("scrollLeft('"+div_name+"')",50);
}

function start_scrollRight(div_name){
	stop_scrollLeftRight();
	scroll_leftright_id = window.setInterval("scrollRight('"+div_name+"')",50);
}

function stop_scrollLeftRight(){
	if(scroll_leftright_id){
		window.clearInterval(scroll_leftright_id);
		scroll_updown_id = 0;
	}
}