// Snow Effect Javascript
// copyright 19th November 2004, 20th July 2006 by Stephen Chapman
// permission to use this Javascript on your web page is granted
// provided that all of the code in this script (including these
// comments) is used without any alteration
// you can change the number of snow flakes if you like

//var num_flakes = 10;
//var snowflakes = new Array("./image/snowflake.gif","./image/snowflake1.gif");
//var upd_speed = 50;

// DOM test
var aDOM = 0, ieDOM = 0, nsDOM = 0;
var stdDOM = document.getElementById;

if (stdDOM)
  aDOM = 1;
else {
  ieDOM = document.all;
  if (ieDOM)
    aDOM = 1;
  else {
    var nsDOM = ((navigator.appName.indexOf('Netscape') != -1)
                              && (parseInt(navigator.appVersion) ==4));
    if (nsDOM) aDOM = 1;
  }
}

function findDOM(objectId, wS) {
  if (stdDOM)
    return wS ? document.getElementById(objectId).style:
  document.getElementById(objectId);
  if (ieDOM)
    return wS ? document.all[objectId].style: document.all[objectId];
  if (nsDOM)
    return document.layers[objectId];
}

// window size tests
function findLivePageWidth() {
  return window.innerWidth != null? window.innerWidth : document.documentElement &&              document.documentElement.clientWidth ? document.documentElement.clientWidth : document.body != null ? document.body.clientWidth :700;
}

function findLivePageHeight() {
   return  window.innerHeight != null? window.innerHeight : document.documentElement && document.documentElement.clientHeight ?  document.documentElement.clientHeight : document.body != null? document.body.clientHeight :500;
}

function posX() {
  return typeof window.pageXOffset != 'undefined' ? window.pageXOffset:document.documentElement.scrollLeft? document.documentElement.scrollLeft:document.body.scrollLeft? document.body.scrollLeft:0;
}

function posY() {
  return typeof window.pageYOffset != 'undefined' ? window.pageYOffset:document.documentElement.scrollTop? document.documentElement.scrollTop: document.body.scrollTop?document.body.scrollTop:0;
}

// make it snow
var movw = new Array();
var movh = new Array();
var move = new Array();
var stepw = new Array();
var steph = new Array();
var posw = new Array();
var posh = new Array();
var dir = new Array();
var winWidth;var winHeight;

function moreSnow() {
  for (var i = 0; i < num_flakes; i++) {
    if (posh[i] > winHeight-50) {
      posw[i] = 10 + Math.random()*(winWidth-movw[i]-30);
      posh[i] = 0;
      dir[i] = (Math.random()<0.5)?1:-1;
      stepw[i] = 0.02 + Math.random()/9;
      steph[i] = 1.3 + Math.random();
    }
    move[i] += stepw[i] *dir[i];
    if (Math.abs(move[i]) > 3) {
      dir[i] = -dir[i];
      posh[i] += Math.abs(movh[i]*move[i]);
      posw[i] += movw[i]*move[i];
      move[i]=0;
    }
    objstyle = findDOM('snow'+i,1);
    objstyle.left = (posX() + posw[i] + movw[i]*move[i])+'px';
    objstyle.top = (posY() + posh[i] + movh[i]*(Math.abs(Math.cos(move[i])+move[i])))+'px';
    objstyle.visibility = 'visible';
  }
  setTimeout("moreSnow()", upd_speed);
}

function startSnow() {
  winWidth = findLivePageWidth() - 75;
  winHeight = findLivePageHeight() - 50;
  for (var i = 0; i < num_flakes; i++) {
    move[i] = 0;
    movh[i] = 12 +  Math.random() * 2;
    movw[i] = 11 +  Math.random() * 4;
    posw[i] = Math.random() * (winWidth-35) + 12;
    posh[i] = Math.random() * winHeight;
    stepw[i] = 0.02 + Math.random() / 10;
    steph[i] = 0.7 + Math.random();
    dir[i] = (Math.random()>0.5)?1:-1;
    document.write('<div id="snow'+ i +'" style="position: absolute; z-index: '+ i +'; visibility:hidden; "><img src="'+snowflakes[Math.floor(Math.random()*snowflakes.length)]+ '" border="0"></div>');
  }
  setTimeout("moreSnow()", upd_speed);
}