雪花代码

<style type="text/css">
.large-header {background: #333;}
</style>
 
<div id="large-header" class="large-header" style="height: 711px;"> </div>    
<!-- 雪花 -->
<script type="text/javascript" language="javascript">
(function(){function k(a,b,c)
{if(a.addEventListener)a.addEventListener(b,c,false);
else a.attachEvent&&a.attachEvent("on"+b,c)
}function g(a){if(typeof window.onload!="function")window.onload=a;
else{var b=window.onload;window.onload=function(){b();a()
}
}
}function h(){
var a={};
for(type in{Top:"",Left:""})
{var b=type=="Top"?"Y":"X";
if(typeof window["page"+b+"Offset"]!="undefined")a[type.toLowerCase()]=window["page"+b+"Offset"];
else{b=document.documentElement.clientHeight?document.documentElement:document.body; 
a[type.toLowerCase()]=b["scroll"+type]}}return a}
function l(){var a=document.body,b;
if(window.innerHeight)b=window.innerHeight;
else if(a.parentElement.clientHeight)b=a.parentElement.clientHeight;
else if(a&&a.clientHeight)b=a.clientHeight;
return b
}
function i(a){
this.parent=document.body;
this.createEl(this.parent,a);
this.size=Math.random()*5+5;
this.el.style.width=Math.round(this.size)+"px";
this.el.style.height=Math.round(this.size)+"px";
this.maxLeft=document.body.offsetWidth-this.size;
this.maxTop=document.body.offsetHeight- this.size;
this.left=Math.random()*this.maxLeft;
this.top=h().top+1;
this.angle=1.4+0.2*Math.random();
this.minAngle=1.4;
this.maxAngle=1.6;
this.angleDelta=0.01*Math.random();
this.speed=2+Math.random()
}
var j=false;
g(function(){j=true});
var f=true;
window.createSnow=function(a,b){if(j){
var c=[],m=setInterval(function(){
f&&b>c.length&&Math.random()<b*0.0025&&c.push(new i(a));
!f&&!c.length&&clearInterval(m);
for(var e=h().top,n=l(),d=c.length-1;d>=0;
d--)if(c[d])if(c[d].top<e||c[d].top+c[d].size+1>e+n){c[d].remove();
 c[d]=null;
 c.splice(d,1)}else{c[d].move();c[d].draw()}},40);
 k(window,"scroll",function()
 {for(var e=c.length-1;e>=0;e--)c[e].draw()})}
 else g(function(){createSnow(a,b)})};
 window.removeSnow=function(){f=false};
 i.prototype={createEl:function(a,b){
 this.el=document.createElement("img");
 this.el.setAttribute("src",b+"http://mimg.127.net/hxm/quan/hd/111207_sdj/style/img/snow.gif");
 this.el.style.position="absolute";
 this.el.style.display="block";
 this.el.style.zIndex="99999";
 this.parent.appendChild(this.el)},move:function(){
 if(this.angle< this.minAngle||this.angle>this.maxAngle)this.angleDelta=-this.angleDelta;
 this.angle+=this.angleDelta;
 this.left+=this.speed*Math.cos(this.angle*Math.PI);
 this.top-=this.speed*Math.sin(this.angle*Math.PI);
 if(this.left<0)this.left=this.maxLeft;
 else if(this.left>this.maxLeft)this.left=0},draw:function(){
 this.el.style.top=Math.round(this.top)+"px";
 this.el.style.left=Math.round(this.left)+"px"},remove:function(){this.parent.removeChild(this.el);
 this.parent=this.el=null}}})();
createSnow("", 80); 
</script>