i found this code Here

Code:
<!--Simply copy and paste into <BODY>  
     Just above the </BODY> tag. -->

<SCRIPT type="text/javascript">
/*
Snow Fall 1 - no images - Java Script
Visit http://rainbow.arch.scriptmania.com/scripts/
  for this script and many more
*/

// Set the number of snowflakes (more than 30 - 40 not recommended)
var snowmax=35

// Set the colors for the snow. Add as many colors as you like
var snowcolor=new Array("#AAAACC","#DDDDFF","#CCCCDD","#F3F3F3","#F0FFFF")

// Set the fonts, that create the snowflakes. Add as many fonts as you like
var snowtype=new Array("Arial Black","Arial Narrow","Times","Comic Sans MS")

// Set the letter that creates your snowflake (recommended: * )
var snowletter="*"

// Set the speed of sinking (recommended values range from 0.3 to 2)
var sinkspeed=0.6

// Set the maximum-size of your snowflakes
var snowmaxsize=22

// Set the minimal-size of your snowflakes
var snowminsize=8

// Set the snowing-zone
// Set 1 for all-over-snowing, set 2 for left-side-snowing 
// Set 3 for center-snowing, set 4 for right-side-snowing
var snowingzone=1

  /*
   //   * NO CONFIGURATION BELOW HERE *
*/

// Do not edit below this line
var snow=new Array()
var marginbottom
var marginright
var timer
var i_snow=0
var x_mv=new Array();
var crds=new Array();
var lftrght=new Array();
var browserinfos=navigator.userAgent 
var ie5=document.all&&document.getElementById&&!browserinfos.match(/Opera/)
var ns6=document.getElementById&&!document.all
var opera=browserinfos.match(/Opera/)  
var browserok=ie5||ns6||opera

function randommaker(range) {		
	rand=Math.floor(range*Math.random())
    return rand
}

function initsnow() {
	if (ie5 || opera) {
		marginbottom = document.body.clientHeight
		marginright = document.body.clientWidth
	}
	else if (ns6) {
		marginbottom = window.innerHeight
		marginright = window.innerWidth
	}
	var snowsizerange=snowmaxsize-snowminsize
	for (i=0;i<=snowmax;i++) {
		crds[i] = 0;                      
    	lftrght[i] = Math.random()*15;         
    	x_mv[i] = 0.03 + Math.random()/10;
		snow[i]=document.getElementById("s"+i)
		snow[i].style.fontFamily=snowtype[randommaker(snowtype.length)]
		snow[i].size=randommaker(snowsizerange)+snowminsize
		snow[i].style.fontSize=snow[i].size
		snow[i].style.color=snowcolor[randommaker(snowcolor.length)]
		snow[i].sink=sinkspeed*snow[i].size/5
		if (snowingzone==1) {snow[i].posx=randommaker(marginright-snow[i].size)}
		if (snowingzone==2) {snow[i].posx=randommaker(marginright/2-snow[i].size)}
		if (snowingzone==3) {snow[i].posx=randommaker(marginright/2-snow[i].size)+marginright/4}
		if (snowingzone==4) {snow[i].posx=randommaker(marginright/2-snow[i].size)+marginright/2}
		snow[i].posy=randommaker(2*marginbottom-marginbottom-2*snow[i].size)
		snow[i].style.left=snow[i].posx
		snow[i].style.top=snow[i].posy
	}
	movesnow()
}

function movesnow() {
	for (i=0;i<=snowmax;i++) {
		crds[i] += x_mv[i];
		snow[i].posy+=snow[i].sink
		snow[i].style.left=snow[i].posx+lftrght[i]*Math.sin(crds[i]);
		snow[i].style.top=snow[i].posy
		
		if (snow[i].posy>=marginbottom-2*snow[i].size || parseInt(snow[i].style.left)>(marginright-3*lftrght[i])){
			if (snowingzone==1) {snow[i].posx=randommaker(marginright-snow[i].size)}
			if (snowingzone==2) {snow[i].posx=randommaker(marginright/2-snow[i].size)}
			if (snowingzone==3) {snow[i].posx=randommaker(marginright/2-snow[i].size)+marginright/4}
			if (snowingzone==4) {snow[i].posx=randommaker(marginright/2-snow[i].size)+marginright/2}
			snow[i].posy=0
		}
	}
	var timer=setTimeout("movesnow()",50)
}

for (i=0;i<=snowmax;i++) {
	document.write("<span id='s"+i+"' style='position:absolute;top:-"+snowmaxsize+"'>"+snowletter+"</span>")
}
if (browserok) {
	window.onload=initsnow
}
</SCRIPT>
I am not very good at Javascript, so i was wondering if theres anyone on here who can make it so the snow can land on the top of set layers with a certain className...

Thanks in advance
Vinny

p.s. I will make an example pic in photoshop and post the link to it here...