Here's a different one for you, as used on my site:
//Snow - http://www.btinternet.com/~kurt.grigg/javascript
if ((document.getElementById) &&
window.addEventListener || window.attachEvent){
(function(){
//Configure here.
var num = 40; //Number of flakes
var timer = 30; //setTimeout speed. Varies on different comps
//End.
var y = [];
var x = [];
var fall = [];
var theFlakes = [];
var sfs = [];
var step = [];
var currStep = [];
var h,w,r;
var d = document;
var pix = "px";
var domWw = (typeof window.innerWidth == "number");
var domSy = (typeof window.pageYOffset == "number");
var idx = d.getElementsByTagName('div').length;
if (d.documentElement.style &&
typeof d.documentElement.style.MozOpacity == "string")
num = 12;
for (i = 0; i < num; i++){
sfs[i] = Math.round(1 + Math.random() * 1);
document.write('<div id="flake'+(idx+i)+'" style="position:absolute;top:0px;left:0px;width:'
+sfs[i]+'px;height:'+sfs[i]+'px;background-color:#ffffff;font-size:'+sfs[i]+'px"><\/div>');
currStep[i] = 0;
fall[i] = (sfs[i] == 1)?
Math.round(2 + Math.random() * 2): Math.round(3 + Math.random() * 2);
step[i] = (sfs[i] == 1)?
0.05 + Math.random() * 0.1 : 0.05 + Math.random() * 0.05 ;
}
if (domWw) r = window;
else{
if (d.documentElement &&
typeof d.documentElement.clientWidth == "number" &&
d.documentElement.clientWidth != 0)
r = d.documentElement;
else{
if (d.body &&
typeof d.body.clientWidth == "number")
r = d.body;
}
}
function winsize(){
var oh,sy,ow,sx,rh,rw;
if (domWw){
if (d.documentElement && d.defaultView &&
typeof d.defaultView.scrollMaxY == "number"){
oh = d.documentElement.offsetHeight;
sy = d.defaultView.scrollMaxY;
ow = d.documentElement.offsetWidth;
sx = d.defaultView.scrollMaxX;
rh = oh-sy;
rw = ow-sx;
}
else{
rh = r.innerHeight;
rw = r.innerWidth;
}
h = rh - 2;
w = rw - 2;
}
else{
h = r.clientHeight - 2;
w = r.clientWidth - 2;
}
}
function scrl(yx){
var y,x;
if (domSy){
y = r.pageYOffset;
x = r.pageXOffset;
}
else{
y = r.scrollTop;
x = r.scrollLeft;
}
return (yx == 0)?y:x;
}
function snow(){
var dy,dx;
for (i = 0; i < num; i++){
dy = fall[i];
dx = fall[i] * Math.cos(currStep[i]);
y[i]+=dy;
x[i]+=dx;
if (x[i] >= w || y[i] >= h){
y[i] = -10;
x[i] = Math.round(Math.random() * w);
fall[i] = (sfs[i] == 1)?
Math.round(2 + Math.random() * 2): Math.round(3 + Math.random() * 2);
step[i] = (sfs[i] == 1)?
0.05 + Math.random() * 0.1 : 0.05 + Math.random() * 0.05 ;
}
theFlakes[i].top = y[i] + scrl(0) + pix;
theFlakes[i].left = x[i] + scrl(1) + pix;
currStep[i]+=step[i];
}
setTimeout(snow,timer);
}
function init(){
winsize();
for (i = 0; i < num; i++){
theFlakes[i] = document.getElementById("flake"+(idx+i)).style;
y[i] = Math.round(Math.random()*h);
x[i] = Math.round(Math.random()*w);
}
snow();
}
if (window.addEventListener){
window.addEventListener("resize",winsize,false);
window.addEventListener("load",init,false);
}
else if (window.attachEvent){
window.attachEvent("onresize",winsize);
window.attachEvent("onload",init);
}
})();
}//End.
To embed, use this code on any html page on your site, making sure to replace the "yoursite.com/path/to" with the correct path:
<script type="text/javascript" src="http://www.yoursite.com/path/to/snow.js"></script>