[Resolvido] Dúvida - neve cair sobre o fórum

/******************************************
* Snow Effect Script- By Altan d.o.o. (http://www.altan.hr/snow/index.html)
******************************************/

//Localização da imagem do floco de neve
var snowsrc="http://astuforum.free.fr/images/neige-mini.gif"
// Quantidade de flocos de neve na tela
var no = 10;
// Configure whether snow should disappear after x seconds (0=never):
var hidesnowtime = 0;
// Configure how much snow should drop down before fading ("windowheight" or "pageheight")
var snowdistance = "pageheight";

///////////Stop Config//////////////////////////////////

var ie4up = (document.all) ? 1 : 0;
var ns6up = (document.getElementById&&!document.all) ? 1 : 0;

function iecompattest(){
return (document.compatMode && document.compatMode!="BackCompat")? document.documentElement : document.body
}

var dx, xp, yp; // coordinate and position variables
var am, stx, sty; // amplitude and step variables
var i, doc_width = 800, doc_height = 600;

if (ns6up) {
doc_width = self.innerWidth;
doc_height = self.innerHeight;
} else if (ie4up) {
doc_width = iecompattest().clientWidth;
doc_height = iecompattest().clientHeight;
}

dx = new Array();
xp = new Array();
yp = new Array();
am = new Array();
stx = new Array();
sty = new Array();
snowsrc=(snowsrc.indexOf("dynamicdrive.com")!=-1)? "snow.gif" : snowsrc
for (i = 0; i < no; ++ i) {
dx[i] = 0; // set coordinate variables
xp[i] = Math.random()*(doc_width-50); // set position variables
yp[i] = Math.random()*doc_height;
am[i] = Math.random()*20; // set amplitude variables
stx[i] = 0.02 + Math.random()/10; // set step variables
sty[i] = 0.7 + Math.random(); // set step variables
if (ie4up||ns6up) {
if (i == 0) {
document.write("<div id="dot"+ i +"" style="POSITION: absolute; Z-INDEX: "+ i +"; VISIBILITY: visible; TOP: 15px; LEFT: 15px;"><a href="http://dynamicdrive.com"><img src='"+snowsrc+"' border="0"><\/a><\/div>");
} else {
document.write("<div id="dot"+ i +"" style="POSITION: absolute; Z-INDEX: "+ i +"; VISIBILITY: visible; TOP: 15px; LEFT: 15px;"><img src='"+snowsrc+"' border="0"><\/div>");
}
}
}

function snowIE_NS6() { // IE and NS6 main animation function
doc_width = ns6up?window.innerWidth-10 : iecompattest().clientWidth-10;
doc_height=(window.innerHeight && snowdistance=="windowheight")? window.innerHeight : (ie4up && snowdistance=="windowheight")? iecompattest().clientHeight : (ie4up && !window.opera && snowdistance=="pageheight")? iecompattest().scrollHeight : iecompattest().offsetHeight;
for (i = 0; i < no; ++ i) { // iterate for every dot
yp[i] += sty[i];
if (yp[i] > doc_height-50) {
xp[i] = Math.random()*(doc_width-am[i]-30);
yp[i] = 0;
stx[i] = 0.02 + Math.random()/10;
sty[i] = 0.7 + Math.random();
}
dx[i] += stx[i];
document.getElementById("dot"+i).style.top=yp[i]+"px";
document.getElementById("dot"+i).style.left=xp[i] + am[i]*Math.sin(dx[i])+"px";
}
snowtimer=setTimeout("snowIE_NS6()", 10);
}

function hidesnow(){
if (window.snowtimer) clearTimeout(snowtimer)
for (i=0; i<no; i++) document.getElementById("dot"+i).style.visibility="hidden"
}


if (ie4up||ns6up){
snowIE_NS6();
if (hidesnowtime>0)
setTimeout("hidesnow()", hidesnowtime*1000)
}