// rollover

var yomotsuRollover = {
	
	preLoad : {},
	main : function() {
		var img = document.images, i, preLoadImg;
		
		for (i = 0; i <img.length; i++) {
			if ((img[i].src.match(/.*_off\./))||(img[i].style.filter)){
				
				var preLoadImg = new Image;
				preLoadImg.src = img[i].src.replace('_off.', '_on.');
				yomotsuRollover.preLoad[img[i].src] = preLoadImg.src;

				img[i].onmouseover = yomotsuRollover.over;
				img[i].onmouseout  = yomotsuRollover.out;
			}
		}
	},
	
	over : function() {
		var imgSrc, preLoadImgSrc;
		if((this.style.filter)&&(this.style.filter.match(/_off\.png/))){//(IE5.5-6 && png)
			imgSrc = (this.style.filter.match(/src=.*\)/)+"").slice(5,-2);
			preLoadImgSrc = yomotsuRollover.preLoad[imgSrc];
			this.style.filter = this.style.filter.replace(imgSrc, preLoadImgSrc);
		}
		else{
			this.src = yomotsuRollover.preLoad[this.src];
		}
	},

	out : function(){
		if((this.style.filter)&&(this.style.filter.match(/_on\.png/))){//(IE5.5-6 && png)
			this.style.filter = this.style.filter.replace('_on.png', '_off.png');
		}
		else{
			this.src = this.src.replace('_on.', '_off.');
		}
	},

	addEvent : function(){
		try {
			window.addEventListener('load', this.main, false);
		} catch (e) {
			window.attachEvent('onload', this.main);
		}
	}
}

yomotsuRollover.addEvent();



// scroll


function pageScrollToTop(){
	var speed1 = 4;
	var speed2 = 5;
	var sec = 20;
	var y;
	var cy;
	var gy = 0;
	var scrollEngine;
	if(document.all){
		cy = document.documentElement.scrollTop;
	}
	else if(document.layers || document.getElementById){
		cy = pageYOffset;
	}
	y = cy-gy;
	if(Math.abs(y)>50){
		cy = Math.round(cy-(y/speed1));
		window.scroll(0,cy);
		scrollEngine = setTimeout("pageScrollToTop()",sec);	
	}else if(Math.abs(y)>2){
		cy = Math.round(cy-(y/speed2));
		window.scroll(0,cy);
		scrollEngine = setTimeout("pageScrollToTop()",sec);	
	}else{
		window.scroll(0,0);
		clearTimeout(scrollEngine);
	}
}