Javascript - Một số hiệu ứng tuyết rơi cho web

<script>
 // CREDITS: // Snowmaker Copyright (c) 2003 Peter Gehrig. All rights reserved.
 // Distributed by http://www.hypergurl.com // Permission given to use the script
 on webpages provided that this notice remains as is. // 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")
 // 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 maximal-size of your snowflaxes var
 snowmaxsize=22 // Set the minimal-size of your snowflaxes 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=3  /////////////////////////////////////////////////////////////////////////// 
 // CONFIGURATION ENDS 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>

<script>
 var SNOW_Picture = "/billeder/snow.gif";
var SNOW_no = 15;

var SNOW_browser_IE_NS = (document.body.clientHeight) ? 1 : 0;
var SNOW_browser_MOZ = (self.innerWidth) ? 1 : 0;
var SNOW_browser_IE7 = (document.documentElement.clientHeight) ? 1 : 0;

var SNOW_Time;
var SNOW_dx, SNOW_xp, SNOW_yp;
var SNOW_am, SNOW_stx, SNOW_sty;
var i, SNOW_Browser_Width, SNOW_Browser_Height;

if (SNOW_browser_IE_NS)
{
 SNOW_Browser_Width = document.body.clientWidth;
 SNOW_Browser_Height = document.body.clientHeight;
}
else if (SNOW_browser_MOZ)
{
 SNOW_Browser_Width = self.innerWidth - 20;
 SNOW_Browser_Height = self.innerHeight;
}
else if (SNOW_browser_IE7)
{
 SNOW_Browser_Width = document.documentElement.clientWidth;
 SNOW_Browser_Height = document.documentElement.clientHeight;
}


SNOW_dx = new Array();
SNOW_xp = new Array();
SNOW_yp = new Array();
SNOW_am = new Array();
SNOW_stx = new Array();
SNOW_sty = new Array();

for (i = 0; i < SNOW_no; ++ i)
{
 SNOW_dx[i] = 0;
 SNOW_xp[i] = Math.random()*(SNOW_Browser_Width-50);
 SNOW_yp[i] = Math.random()*SNOW_Browser_Height;
 SNOW_am[i] = Math.random()*20;
 SNOW_stx[i] = 0.02 + Math.random()/10;
 SNOW_sty[i] = 0.7 + Math.random();
 if (i == 0) document.write("<\div id="SNOW_flake"+ i +"" style="position: absolute; z-index: "+ i +"; visibility: visible; top: 15px; left: 15px;"><a href="http://www.peters1.dk" target="_blank"><\img src=""+SNOW_Picture+"" border="0"></a><\/div>");
 else document.write("<\div id="SNOW_flake"+ i +"" style="position: absolute; z-index: "+ i +"; visibility: visible; top: 15px; left: 15px;"><\img src=""+SNOW_Picture+"" border="0"><\/div>");
}

function SNOW_Weather()
{

for (i = 0; i < SNOW_no; ++ i)
{
 SNOW_yp[i] += SNOW_sty[i];

 if (SNOW_yp[i] > SNOW_Browser_Height-50)
 {
 SNOW_xp[i] = Math.random()*(SNOW_Browser_Width-SNOW_am[i]-30);
 SNOW_yp[i] = 0;
 SNOW_stx[i] = 0.02 + Math.random()/10;
 SNOW_sty[i] = 0.7 + Math.random();
 }

 SNOW_dx[i] += SNOW_stx[i];

 document.getElementById("SNOW_flake"+i).style.top=SNOW_yp[i]+"px";
 document.getElementById("SNOW_flake"+i).style.left=SNOW_xp[i] + SNOW_am[i]*Math.sin(SNOW_dx[i])+"px";
}

SNOW_Time = setTimeout("SNOW_Weather()", 10);

}

SNOW_Weather();
 </script>

<script type="text/javascript" name="snow.js">
if  ((document.getElementById) &&
window.addEventListener || window.attachEvent){

(function(){

//Configure here.

var num = 60;  //Number of flakes
var timer = 30; //setTimeout speed. Varies on different comps

//End.

var y = [];
var x = [];
var fall = [];
var theFlakes = [];
var sfs = [];
var step = [];
var currStep = [];
var h,w,r;
var d = document;
var pix = "px";
var domWw = (typeof window.innerWidth == "number");
var domSy = (typeof window.pageYOffset == "number");
var idx = d.getElementsByTagName('div').length;

if (d.documentElement.style &&
typeof d.documentElement.style.MozOpacity == "string")
num = 12;

for (i = 0; i < num; i++){
sfs[i] = Math.round(1 + Math.random() * 1);

document.write('<div id="flake'+(idx+i)+'" style="position:absolute;top:0px;left:0px;width:'
+sfs[i]+'px;height:'+sfs[i]+'px;background-color:#ffffff;font-size:'+sfs[i]+'px"><\/div>');

currStep[i] = 0;
fall[i] = (sfs[i] == 1)?
Math.round(2 + Math.random() * 2): Math.round(3 + Math.random() * 2);
step[i] = (sfs[i] == 1)?
0.05 + Math.random() * 0.1 : 0.05 + Math.random() * 0.05 ;
}


if (domWw) r = window;
else{
 if (d.documentElement &&
 typeof d.documentElement.clientWidth == "number" &&
 d.documentElement.clientWidth != 0)
 r = d.documentElement;
 else{
 if (d.body &&
 typeof d.body.clientWidth == "number")
 r = d.body;
 }
}


function winsize(){
var oh,sy,ow,sx,rh,rw;
if (domWw){
 if (d.documentElement && d.defaultView &&
 typeof d.defaultView.scrollMaxY == "number"){
 oh = d.documentElement.offsetHeight;
 sy = d.defaultView.scrollMaxY;
 ow = d.documentElement.offsetWidth;
 sx = d.defaultView.scrollMaxX;
 rh = oh-sy;
 rw = ow-sx;
 }
 else{
 rh = r.innerHeight;
 rw = r.innerWidth;
 }
h = rh - 2; 
w = rw - 2;
}
else{
h = r.clientHeight - 2;
w = r.clientWidth - 2;
}
}


function scrl(yx){
var y,x;
if (domSy){
 y = r.pageYOffset;
 x = r.pageXOffset;
 }
else{
 y = r.scrollTop;
 x = r.scrollLeft;
 }
return (yx == 0)?y:x;
}


function snow(){
var dy,dx;

for (i = 0; i < num; i++){
 dy = fall[i];
 dx = fall[i] * Math.cos(currStep[i]);

 y[i]+=dy;
 x[i]+=dx;

 if (x[i] >= w || y[i] >= h){
 y[i] = -10;
 x[i] = Math.round(Math.random() * w);
 fall[i] = (sfs[i] == 1)?
 Math.round(2 + Math.random() * 2): Math.round(3 + Math.random() * 2);
 step[i] = (sfs[i] == 1)?
 0.05 + Math.random() * 0.1 : 0.05 + Math.random() * 0.05 ;
 }
 
 theFlakes[i].top = y[i] + scrl(0) + pix;
 theFlakes[i].left = x[i] + scrl(1) + pix;

 currStep[i]+=step[i];
}
setTimeout(snow,timer);
}


function init(){
winsize();
for (i = 0; i < num; i++){
 theFlakes[i] = document.getElementById("flake"+(idx+i)).style;
 y[i] = Math.round(Math.random()*h);
 x[i] = Math.round(Math.random()*w);
}
snow();
}


if (window.addEventListener){
 window.addEventListener("resize",winsize,false);
 window.addEventListener("load",init,false);
} 
else if (window.attachEvent){
 window.attachEvent("onresize",winsize);
 window.attachEvent("onload",init);
}

})();
}//End.
</script>