/**************************************************************
1. 스크롤
2. 작성자 : 2007.11.15 Append by KMS
3. 사용법
LeftPhotoScroll=new ktpageScroll();	
//함수 선언
LeftPhotoScroll.name="LeftPhotoScroll";		
//이름 선언
LeftPhotoScroll.AddLayer('Bin_Scroll','photoscroll');
//사용할 레이어 입력('초기위치 레이어','스크롤될 레이어')
LeftPhotoScroll.InitScrollPhoto(_hkADHT,_hkBTTM);
//스크롤 시작('스크롤 레이어 높이','하단 경계영역');
**************************************************************/
function ktpageScroll()
{
	//왼쪽 따라다니는 메뉴
	this._hkGAP 	=10;        // 위쪽 여백
	this._hkINIT 	=0;   		// 시작위치(메뉴높이 + 최상단에서 메뉴까지거리)
	this._hkBTTM 	=0;			// 하단 경계 높이
	this._hkADHT	=0;			// 스크롤 레이어 높이
	this._hkMaxSCHT	=0;			// 전체 스크롤 영역

	this._hkRefreshVal = 120;	// 스크롤 타임
	this._hkScrollSpeed = 2;	// 스크롤 스피드
	this._hkTimer;

	this._FLayer;
	this._SLayer;
	this.name="ktpageScroll";
	
	this.AddLayer = function(FLayer,SLayer){
		this._FLayer = document.getElementById(FLayer);
		this._SLayer = document.getElementById(SLayer);
	};
	
	this.RefreshScrollPhoto = function() {
		var _hkStartPoint, _hkEndPoint, _hkRefreshTime,_hkScrollAmount;

		_hkStartPoint = parseInt(this._SLayer.style.top, 10);
		_hkEndPoint = document.body.scrollTop + this._hkGAP;

		if(_hkEndPoint < this._hkINIT) _hkEndPoint = this._hkINIT;
		if(_hkEndPoint > (this._hkMaxSCHT-this._hkADHT-this._hkBTTM)) _hkEndPoint = this._hkMaxSCHT-this._hkADHT-this._hkBTTM;

		_hkRefreshTime = this._hkRefreshVal;
		if(_hkStartPoint != _hkEndPoint && _hkEndPoint <= (this._hkMaxSCHT - this._hkADHT - this._hkBTTM) && _hkEndPoint >= this._hkINIT) {
			this._hkScrollAmount = Math.ceil(Math.abs(_hkEndPoint - _hkStartPoint) / 15);
			this._SLayer.style.top = _hkStartPoint + ((_hkEndPoint<_hkStartPoint) ? -this._hkScrollAmount : this._hkScrollAmount);
			_hkRefreshTime = this._hkScrollSpeed;
		}
		this._hkTimer = setTimeout(this.name+".RefreshScrollPhoto()",_hkRefreshTime);
	};
	
	this.InitScrollPhoto = function(_hkADHT,_hkBTTM){
		this._hkADHT=_hkADHT;
		this._hkBTTM=_hkBTTM;
		this._hkINIT=this._FLayer.offsetTop+this._hkGAP;
		this._SLayer.style.top = this._hkINIT+"px";
		this._hkMaxSCHT=document.body.scrollHeight;
		this.RefreshScrollPhoto();
	};
}