var scrllInterval = null;

var scrllFF       = document.getElementById && !document.all;

function scrollAreaUp(){
	scrollAreaStop();
	doScrollUp();
	scrllInterval = window.setInterval('doScrollUp();',125);
	return true;	
}

function doScrollUp(){
	var area = document.getElementById("main_scroll");
	if (scrllFF){
		if (area.scrollTop >= 10)
			area.scrollTop -= 12;
		else {
			area.scrollTop = 0;
			if (scrllInterval) window.clearInterval(scrllInterval);
		}
	}else{
		if (area.scrollTop >= 10)
			area.scrollTop -= 12;
		else {
			area.scrollTop = 0;
			if (scrllInterval) window.clearInterval(scrllInterval);
		}
	}
}

function doScrollDown(){
	var area = document.getElementById("main_scroll");
	var sctop = area.scrollTop;
	area.scrollTop += 12;
	if (area.scrollTop == sctop){
		if (scrllInterval) window.clearInterval(scrllInterval);
	}	
}

function scrollAreaDown(){
	scrollAreaStop();
	doScrollDown();
	scrllInterval = window.setInterval('doScrollDown();',125);
	return true;
}

function scrollAreaStop(){
	if (scrllInterval)
		window.clearInterval(scrllInterval);
	return true;		
}

function scrollInit(){
	var imgup = document.getElementById("scroll_up");
	var imgdn = document.getElementById("scroll_dn");
	if (scrllFF){
		imgup.addEventListener('onmouseover',scrollAreaUp,false);
		imgdn.addEventListener('onmouseout',scrollAreaDown,false);
	}else{
		imgup.attachEvent('onmouseover',scrollAreaUp);
		imgdn.attachEvent('onmouseout',scrollAreaDown);	
	}
}

function switchImage(imgID,imgFile){
	var img = document.getElementById(imgID);
	img.src = imgFile;
	return true;
}