var starnum=40;  
var vscrolladjust = 1;

var starcolors=['#dddddd','#000099', '#2222aa'];

var star=new Array();
var so=new Object();
so.ie4=(document.all&&!document.getElementById)?true:false;
so.ns4=(document.layers)?true:false;
so.ie5=(document.all&&document.getElementById)?true:false;
so.ns6=(document.getElementById&&!document.layers&&!document.all)?true:false;
so.w3c=(document.getElementById)?true:false;
so.tmpx=0; so.tmpy=0;
so.xdir=0; so.ydir=0;
so.deltax=0; so.deltay=0;
so.xoffset=0; so.yoffset=0;
so.w_x=0; so.w_y=0;
so.scrlx=0; so.scrly=0;

if (so.ns6) {
  vscrolladjust = 0.015;
}

function getid(str){
if(so.ns4)return document.layers[str];
else if(so.ie4)return document.all[str];
else if(so.w3c)return document.getElementById(str);
}

function findwindowparams(){
so.w_x=(so.ie4||so.ie5)?document.body.clientWidth:window.innerWidth;
so.w_y=(so.ie4||so.ie5)?document.body.clientHeight:window.innerHeight;
so.xoffset=Math.floor(so.w_x/2);
so.yoffset=Math.floor(so.w_y/2);
for(i=1;i<=starnum;i++)getstartpos(i);
}

function getstartpos(n){
var sN=star[n];
sN.deltay=Math.floor(Math.random()*15);
sN.deltax=Math.floor(Math.random()*15);
sN.sv=(sN.deltax+sN.deltay)/2+1;
sN.xdir=(Math.floor(Math.random()*2)==1)?true:false;
sN.ydir=(Math.floor(Math.random()*2)==1)?true:false;
sN.ctr=0;
var tsx=(so.ie4||so.ie5)?document.body.scrollLeft:pageXOffset;
var tsy=(so.ie4||so.ie5)?document.body.scrollTop:pageYOffset;
tsy *= vscrolladjust;
if(so.ns4){
sN.clip.width=sN.clip.height=0;
sN.moveTo(so.xoffset+tsx,so.yoffset+tsy);
}else{
sN.style.width=sN.style.height=0; 
sN.style.top=so.yoffset+tsy+'px';
sN.style.left=so.xoffset+tsx+'px';
}}

function movestar(){
for(i=1;i<=starnum;i++){
var sN=star[i];
sN.ctr+=sN.sv/70;
so.tmpx=sN.deltax*sN.ctr+sN.ctr;
so.tmpy=sN.deltay*sN.ctr+sN.ctr;
so.scrlx=(so.ie4||so.ie5)?document.body.scrollLeft:pageXOffset;
so.scrly=(so.ie4||so.ie5)?document.body.scrollTop:pageYOffset;
so.scrly *= vscrolladjust;
var tc=(sN.ctr>.9)?Math.max(1,(sN.ctr/1)):0;
var tx=(so.ns4)?sN.left:parseInt(sN.style.left);
var ty=(so.ns4)?sN.top:parseInt(sN.style.top);
if(so.ns4){
sN.clip.width=sN.clip.height=tc;
if((tx+so.tmpx+tc>=so.w_x+so.scrlx)||(ty+so.tmpy+tc>=so.w_y+so.scrly)||(tx-so.tmpx*1.2<=so.scrlx)||(ty-so.tmpy*1.5<=so.scrly))getstartpos(i);
else sN.moveBy(((sN.xdir)?so.tmpx:-so.tmpx), ((sN.ydir)?so.tmpy:-so.tmpy));
}else{
sN.style.width=sN.style.height=tc;
if((tx+so.tmpx+tc>=so.w_x+so.scrlx)||(ty+so.tmpy+tc>=so.w_y+so.scrly)||(tx-so.tmpx*1.2<=so.scrlx)||(ty-so.tmpy*1.5<=so.scrly))getstartpos(i);
else{
sN.style.top=ty+((sN.ydir)?so.tmpy:-so.tmpy)+'px';
sN.style.left=tx+((sN.xdir)?so.tmpx:-so.tmpx)+'px';
}}}}

window.onresize=function(){
if(so.ns4)setTimeout('history.go(0)',200);
else findwindowparams();
}

window.onload=function(){
for(i=1;i<=starnum;i++)star[i]=getid('star'+i);
findwindowparams();
var d=(so.ns6)?50:80;
setInterval('movestar()',d);
}

function writestars(){
var tc;
var txt='';
for(i=1;i<=starnum;i++){
tc=starcolors[Math.floor(Math.random()*starcolors.length)];
txt+='<div id="star'+i+'" class="star" style="background-color:'+tc+'; layer-background-color:'+tc+'"></div>';
}
return txt;
}

document.write(writestars());