//<!-- Begin
var MAX=1;		//星の数
var SPEED=12		//星が一度に進むドット数
var RAD=0.2;		//星が一度に回転する角度
var WAIT=20;
var scx=0,scy=0;
if(!img) img="star.gif";
var imgObj=new Image();
imgObj.src=img;
var IW,IH;
var load=false;

function SnakePart(x,y,m,before)
{
	this.x=x;
	this.y=y;
	this.m=m;
	this.before=before;
}
function mousemove()
{
	ms.x=window.event.x+scx;
	ms.y=window.event.y+scy;
}
function nextState(snake)
{
	var sx=snake.x-snake.before.x
		,sy=snake.y-snake.before.y;
	var mk=Math.atan(sy/sx);

	if(sx>0 && sy>0) mk+=Math.PI;
	if(sy<0 && sx>0) mk+=Math.PI;
	var b=snake.m-mk, c=mk-snake.m;
	if(c>0 && c<Math.PI*2) b=Math.PI*2-c;
	if(b>0 && b<Math.PI) snake.m-=RAD;
	else snake.m+=RAD;
	snake.m=snake.m%(Math.PI*2);
	snake.x+=Math.cos(snake.m)*SPEED;
	snake.y+=Math.sin(snake.m)*SPEED;
}
function doubleArray(array,n)
{
	for(i=0;i<array.length;i++)
		array[i]=new Array(n);
}

var ns4up=document.layers;
var ie4up=document.all;
var w=600,h=600;
sp=new Array(MAX);
var ms=new SnakePart(w/2,h/2,0,null);
sp[0]=new SnakePart(Math.random()*w,Math.random()*h,Math.random()*(Math.PI*2)-Math.PI,ms);

for(i=1;i<sp.length;i++)
	sp[i]=new SnakePart(Math.random()*w,Math.random()*h,Math.random()*(Math.PI*2)-Math.PI,sp[i-1]);

if(ie4up)
{
	document.write('<div id="iec" style="position:absolute;top:0px;left:0px">');
	document.write('<div id="ch" style="position:relative">');
}
for(i=0;i<MAX;i++)
{
	if(ns4up)
		document.write("<layer name='dot"+i+"' left=0 top=-100 visibility=show><img src='" + img + "' border=0></layer>");
	else if(ie4up)
		document.write("<img src=\"" + img + "\" style=\"position:absolute;top:-100px;left:0px\">");
}

if(ie4up)
	document.write('</div></div>');

function mainIE(){
	if(!load){
		IW=imgObj.width/2; IH=imgObj.height/2;
		if(IW>0 && IH>0) load=true;
	}
	for(i=0;i<sp.length;i++){
		nextState(sp[i]);
		if(Math.abs(sp[i].x-ms.x)>IW+3 || Math.abs(sp[i].y-ms.y)>IH+3){
			iec.all.ch.all[i].style.pixelLeft=sp[i].x-IW;
			iec.all.ch.all[i].style.pixelTop=sp[i].y-IH;
		}else
			sp[i].m+=Math.PI;
	}
}
function mainNS(){
	if(!load){
		IW=imgObj.width/2; IH=imgObj.height/2;
		if(IW>0 && IH>0) load=true;
	}
	for(i=0;i<sp.length;i++){
		nextState(sp[i]);
		if(Math.abs(sp[i].x-ms.x)>10 || Math.abs(sp[i].y-ms.y)>10){
			s="dot"+i;
			document.layers[s].left=sp[i].x-8;
			document.layers[s].top=sp[i].y-8;
		}else
			sp[i].m+=Math.PI;
	}
}
if (ns4up)
	setInterval("mainNS()", WAIT);
else if (ie4up)
	setInterval("mainIE()", WAIT);	

function onscroll()
{
	scx=getScrollPosX();
	scy=getScrollPosY();
}

function getScrollPosX() {
    if (ns4up) return pageXOffset;
    if (ie4up) return document.body.scrollLeft
}

function getScrollPosY() {
    if (ns4up) return pageYOffset;
    if (ie4up) return document.body.scrollTop;
}

// End -->