var _scroll_topmargin = 0;        // 이동 메뉴의 상단 한계 픽셀
var _scroll_ing_topmargin = 10;         // 움직이는 도중의 상단과의 간격
var _scroll_activate_speed = 500;        // 초기 움직임을 감지하는 시간차이 (1/1000초)
var _scroll_ing_activate_speed = 2;        // 움직이기 시작한 이후에 감지하는 시간차이 (1/1000초)
var _move_layer;
 
var isDOM = (document.getElementById ? true : false); 
var isNS4 = (document.layers ? true : false);
var isNS = navigator.appName == "Netscape";
 
function _auto_move_layer() {
	var source_y, target_y, offset_y, time_out;
	if (isNS4) {
		source_y   = document.getElementById(_move_layer).top;
		target_y     = windows.pageYOffset + _scroll_ing_topmargin;
	} else if (isDOM) {
		source_y   = parseInt (document.getElementById(_move_layer).style.top.replace("px",""), 10);
		target_y = (isNS ? window.pageYOffset : document.documentElement.scrollTop) + _scroll_ing_topmargin;
	}
	if(target_y<_scroll_topmargin) target_y = _scroll_topmargin;
	time_out = _scroll_activate_speed;
	if (source_y != target_y) {
		offset_y = Math.ceil(Math.abs(target_y - source_y) / 20);
		if (target_y < source_y) offset_y = -offset_y;
		if (isNS4) document.getElementById(_move_layer).top += offset_y;
		else if (isDOM) document.getElementById(_move_layer).style.top = parseInt (document.getElementById(_move_layer).style.top.replace("px",""), 10) + offset_y+"px";
		time_out = _scroll_ing_activate_speed;
	}
	setTimeout ("_auto_move_layer()", time_out);
}
 
function init_move_layer(move_layer,start_top,topmargin,activate_speed,speed_move_layer) {
	if(start_top) _scroll_topmargin = start_top; 
	if(topmargin) _scroll_ing_topmargin = topmargin;
	if(activate_speed) if(speed_move_layer) _scroll_activate_speed = activate_speed;
	if(speed_move_layer) _scroll_ing_activate_speed = speed_move_layer;
	_move_layer = move_layer;
	var topmargin = parseInt(get_Style(_move_layer,"top").replace("px",""), 10);	
	_scroll_topmargin = topmargin;
	document.getElementById(_move_layer).style.top = (isNS ? window.pageYOffset : document.body.scrollTop) + _scroll_topmargin+"px";
	document.getElementById(_move_layer).style.visibility = "visible";
	_auto_move_layer();
}