var tmrID;

var offsetY = 50;
var beforeY = 50;


// 移動開始処理
function setMenu(){

	clearInterval(tmrID);

	tmrID=setTimeout("mvMenu()",500)

}

// 移動距離計算処理
function mvMenu(){

	var scrollY;	// スクロールされた高さ
	var moveToY;	// 移動先のＹ座標
	var moveByY;	// 今回移動する値（相対値）

	scrollY = document.body.scrollTop;
	moveToY = scrollY+offsetY;
	moveByY = Math.floor((moveToY - beforeY) / 3);
	beforeY = beforeY+moveByY;

	moveByLayer("lyrMenu",0,moveByY);

	if(Math.abs((moveToY-beforeY)) > 1){
		tmrID=setTimeout("mvMenu()",1)
	}

}


// レイヤーを移動する
function moveByLayer(idName,x,y){

	if(document.getElementById){
		var oj = document.getElementById(idName).style;
		oj.left = (parseInt(oj.left) + x ) + 'px';
		oj.top  = (parseInt(oj.top)  + y ) + 'px';
	}else if(document.all){
		document.all(idName).style.pixelLeft += x;
		document.all(idName).style.pixelTop  += y;
	}else if(document.layers){
		document.layers[idName].moveBy(x,y);
	}

}

window.onscroll=setMenu;


var scrj = 1;
function softScrollBack() {
   if(navigator.appName == "Microsoft Internet Explorer" && document.compatMode == "CSS1Compat") {
      var scdist = document.body.parentNode.scrollTop;
   } else {
      var scdist = document.body.scrollTop;
   }
   if(scrj<50 && scdist) {
      scdist = (scdist>2) ? Math.ceil(scdist*.2) : 1;
      scrj++;
      scrollBy(0,-scdist);
      setTimeout("softScrollBack()",20);
   } else {
      scrollTo(0,0);
      scrj = 1;
   }
}