本文实例讲述了JS烟花背景效果实现方法。分享给大家供大家参考。具体实现方法如下：
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>又一个很酷的JS烟花背景特效</title>
<script type="text/javascript">
var fireworks = function(){
this.size = 20;
this.rise();
}
fireworks.prototype = {
color:function(){
var c = ['0','3','6','9','c','f'];
var t = [c[Math.floor(Math.random()*100)%6],'0','f'];
t.sort(function(){return Math.random()>0.5?-1:1;});
return '#'+t.join('');
},
aheight:function(){
var h = document.documentElement.clientHeight-250;
return Math.abs(Math.floor(Math.random()*h-200))+201;
},
firecracker:function(){
var b = document.createElement('div');
var w = document.documentElement.clientWidth;
b.style.position = 'absolute';
b.style.color = this.color();
b.style.bottom = 0;
b.style.left = Math.floor(Math.random()*w)+1+'px';
document.body.appendChild(b);
return b;
},
rise:function(){
var o = this.firecracker();
var n = this.aheight();
var c = this.color;
var e = this.expl;
var s = this.size;
var k = n;
var m = function(){
o.style.bottom = parseFloat(o.style.bottom)+k*0.1+'px';
k-=k*0.1;
if(k<2){
clearInterval(clear);
e(o,n,s,c);
}
}
o.innerHTML = '.';
if(parseInt(o.style.bottom)<n){
var clear = setInterval(m,20);
}
},
expl:function(o,n,s,c){
var R=n/3,Ri=n/6,Rii=n/9;
var r=0,ri=0,rii=0;
for(var i=0;i<s;i++){
var span = document.createElement('span');
var p = document.createElement('i');
var a = document.createElement('a');
span.style.position = 'absolute';
span.style.fontSize = n/10+'px';
span.style.left = 0;
span.style.top = 0;
span.innerHTML = '*';
p.style.position = 'absolute';
p.style.left = 0;
p.style.top = 0;
p.innerHTML = '*';
a.style.position = 'absolute';
a.style.left = 0;
a.style.top = 0;
a.innerHTML = '*';
o.appendChild(span);
o.appendChild(p);
o.appendChild(a);
}
function spr(){
r += R*0.1;
ri+= Ri*0.06;
rii+= Rii*0.06;
sp = o.getElementsByTagName('span');
p = o.getElementsByTagName('i');
a = o.getElementsByTagName('a');
for(var i=0; i<sp.length;i++){
sp[i].style.color = c();
p[i].style.color = c();
a[i].style.color = c();
sp[i].style.left=r*Math.cos(360/s*i)+'px';
sp[i].style.top=r*Math.sin(360/s*i)+'px';
sp[i].style.fontSize=parseFloat(sp[i].style.fontSize)*0.96+'px';
p[i].style.left=ri*Math.cos(360/s*i)+'px';
p[i].style.top=ri*Math.sin(360/s*i)+'px';
p[i].style.fontSize=parseFloat(sp[i].style.fontSize)*0.96+'px';
a[i].style.left=rii*Math.cos(360/s*i)+'px';
a[i].style.top=rii*Math.sin(360/s*i)+'px';
a[i].style.fontSize=parseFloat(sp[i].style.fontSize)*0.96+'px';
}
R-=R*0.1;
if(R<2){
o.innerHTML = '';
o.parentNode.removeChild(o);
clearInterval(clearI);
}
}
var clearI = setInterval(spr,20);
}
}
window.onload = function(){
function happyNewYear(){
new fireworks();
}
setInterval(happyNewYear,1000);
}
</script>
<style type="text/css">
</style>
</head>
<body style="background:#000;font:12px Georgia, 'Times New Roman', Times, serif">
</body>
</html>
运行效果如下所示：
希望本文所述对大家的javascript程序设计有所帮助。
