var y = 0;
var opa = 0;
var fade = 100;
var scr = 100;

function	topimg() {
	opa = 0;
	y = 0;
	img = new Array();
	img[0]="http://www.seibu-bansetsu.com/img/topimg/01.png";
	img[1]="http://www.seibu-bansetsu.com/img/topimg/02.png";
	img[2]="http://www.seibu-bansetsu.com/img/topimg/03.png";
	img[3]="http://www.seibu-bansetsu.com/img/topimg/04.png";
	img[4]="http://www.seibu-bansetsu.com/img/topimg/05.png";
	img[5]="http://www.seibu-bansetsu.com/img/topimg/06.png";
	img[6]="http://www.seibu-bansetsu.com/img/topimg/07.png";
	img[7]="http://www.seibu-bansetsu.com/img/topimg/08.png";
	img[8]="http://www.seibu-bansetsu.com/img/topimg/09.png";
	img[9]="http://www.seibu-bansetsu.com/img/topimg/10.png";
	rand = Math.floor(Math.random()*img.length);
	document.getElementById("topImgBg").style.backgroundImage = "url("+img[rand]+")";
	document.getElementById("topImgBg").style.zIndex = 1;
	scrollup();
}

function fadein() {
	opa = opa+1;
	document.getElementById("topImgBg").style.filter = "alpha(opacity:"+opa+")"; // IE のソース
	document.getElementById("topImgBg").style.opacity = opa/100; //Mozilla Firefoxのソース
	if (opa <= 100) {
		setTimeout("fadein()", fade);
	}
}



function	scrollup() {
	fadein();
	x = 0;
	y = y-1;
	document.getElementById("loading").style.textIndent = -9999+"px";
	document.getElementById("topImgBg").style.backgroundPosition = x+"px "+y+"px";
	if(y > -284) {
		setTimeout("scrollup()", scr);
	}else{
		scrolldown();
		document.getElementById("topImg").style.backgroundImage = "url("+img[rand]+")";
		document.getElementById("topImg").style.zIndex = 0;
	}
}


function	scrolldown() {
	x = 0;
	y = y+1;
	document.getElementById("topImgBg").style.backgroundPosition = x+"px "+y+"px";
	if(y < 0) {
		setTimeout("scrolldown()", scr);
	}else{
		topimg();
	}
}