Z-index beállítása?

a script:

var snowmax=50;

var snowcolor=new Array("#aaaacc","#ddddff","#ccccdd","#f3f3f3","#f0ffff");

//var snowtype=new Array("Times","Arial","Times","Verdana");

var snowtype=new Array("Times","Arial","Tahoma","Verdana");

var snowletter="*";

var sinkspeed=0.6;

var snowmaxsize=30;

var snowminsize=8;

var snowingzone=1;

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.scrollHeight;

marginright = document.body.clientWidth-15;

}

else if(ns6) {

marginbottom = document.body.scrollHeight;

marginright = window.innerWidth-15;

}

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+'px';

snow[i].style.color=snowcolor[randommaker(snowcolor.length)];

snow[i].style.zIndex=1000;

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+'px';

snow[i].style.top=snow[i].posy+'px';

}

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])+'px';

snow[i].style.top=snow[i].posy+'px';

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;

}