var no = 20;var delai = 10;
var dx = new Array(), xp = new Array(), yp = new Array();
var am = new Array(), stx = new Array(), sty = new Array();
var i;

function neige() {
  for (i = 0; i < no; i++) {
    dx[i] += stx[i];
    yp[i] += sty[i];
    if (yp[i] > haut_fenetre-50) {
     xp[i] = Math.random()*(larg_fenetre-am[i]-40);
     yp[i] = 0;
    }

    document.getElementById("dot"+i).style.top = yp[i] + "px";
    document.getElementById("dot"+i).style.left = xp[i] + am[i]*Math.sin(dx[i]) + "px";
    if (!document.all) {
     larg_fenetre = (document.body.offsetWidth<window.innerWidth)? window.innerWidth:document.body.offsetWidth;
     haut_fenetre = (document.body.offsetHeight<window.innerHeight)? window.innerHeight:document.body.offsetHeight;
    }
  }
  setTimeout("neige()", delai);
}

function initialiseNeige(){
   if (document.all) {
     larg_fenetre = document.body.offsetWidth;
     haut_fenetre = document.body.offsetHeight;
   } else {
     larg_fenetre = (document.body.offsetWidth<window.innerWidth)? window.innerWidth:document.body.offsetWidth;
     haut_fenetre = (document.body.offsetHeight<window.innerHeight)? window.innerHeight:document.body.offsetHeight;
   }

   for (i = 0; i < no; i++){ 
     dx[i] = 0;
     xp[i] = Math.random()*(larg_fenetre-40);
     yp[i] = Math.random()*haut_fenetre;
     am[i] = Math.random()*20;
     stx[i] = 0.02 + Math.random()/10;
     sty[i] = 0.7 + Math.random();

     obj = document.getElementsByTagName('body')[0];
     para = document.createElement("img");
     var source = document.createAttribute("src");
     var ident = document.createAttribute("id");
     source.nodeValue = "http://www.europarm.fr/style/neige/neige.gif";
     ident.nodeValue = "dot" + i;
     para.setAttributeNode(source);
     para.setAttributeNode(ident);
     obj.appendChild(para);
     document.getElementById("dot" + i ).className = "flocon"
   }
   
   
   neige();
}   

window.onload = function(){
   initialiseNeige();
};