Simple fireworks special effects code implemented in JavaScript

Simple fireworks special effects code implemented in JavaScript_javascript skills

WBOY

Release： 2016-05-16 15:35:57

Original

2538 people have browsed it

The example in this article describes the simple fireworks special effects code implemented in JavaScript. Share it with everyone for your reference, the details are as follows:

This is a JavaScript firework special effect. Put it on your webpage during the Chinese New Year to wish everyone a happy Year of the Ox. Isn’t it great?

The screenshot of the running effect is as follows:

The online demo address is as follows:

http://demo.jb51.net/js/2015/js-yh-explode-style-demo/

The specific code is as follows:

<!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=gb2312" />
<title>礼花特效</title>
<style type="text/css">
 html,body{background:#000; height:100%; margin:0px; padding:0px;color:#FFF;}
 .ball{color:#FF0000; position:absolute; font-size:16px;}
 .star{color:#FF0000; position:absolute; font-size:4px;}
</style>
<script type="text/javascript">
function Fireworks(sky, loop){
 this.sky = sky;
 this.skyWidth = document.body.clientWidth || document.documentElement.clientWidth;
 this.skyHeight= document.body.clientHeight || document.documentElement.clientHeight;
 this.x = this.y = 0;
 this.step = 20;
 this.delay = 30;
 this.stars = [];
 this.r = 10;
 this.step2 = 7;
 this.radius = 90;
 this.angle = 45;
 this.num = 16;
 this.loop = loop;
 this.degree = 2;
 this.t = 0;
 this.delt = 0;
 this.max = 30;
 this.cur = 1;
 this.points = null;
}
Fireworks.prototype = {
 init : function(){
  this.x = parseInt(this.skyWidth/1.3 * Math.random()) + this.skyWidth / 8;
  this.y = this.skyHeight;
  this._y = parseInt((this.skyHeight / 4) * Math.random()) + this.skyHeight / 5;
 },
 setOpacity : function(obj, p){
  if(p > 85){
   var opacity = 100 - (p - 85) * 4;
   if(document.all){
    obj.style.filter = "alpha(opacity=" + opacity + ")"; 
   }else{
    obj.style.MozOpacity = opacity / 100;
   }
  }
 },
 getNextPoint : function(degree, coeff, t){
  var tt = 1.0 - t;
  for(var rr = 1; rr <= degree; rr++){
   for(var i=0; i <= degree-rr; i++){
    coeff[i] = tt * coeff[i] + t * coeff[i+1];
   }
  }
  return coeff[0];
 },
 showBall : function(){
  this.ball = document.createElement("div");
  this.ball.innerHTML = "●";
  this.ball.className = "ball";
  this.ball.style.left = this.x + "px";
  this.ball.style.top = this.y + "px";
  this.sky.appendChild(this.ball);
 },
 moveBall : function(){
  var self = this;
  if(this.y > this._y){
   var p = parseInt((this.skyHeight - this.y) / (this.skyHeight - this._y)*10);
   this.y -= (this.step - p * 1.6);
   this.ball.style.fontSize = 16 - p + "px";
   this.ball.style.top = this.y + "px";
   setTimeout(function(){self.moveBall();}, this.delay);
  }else{
   this.fire();
  }
 },
 hideBall : function(){
  this.sky.removeChild(this.ball);
  this.ball = null;
 },
 showStars : function(){
  var colors = ['#FF0000','#FF00FF','#00FF00','#00FFFF','#FFFF00','#FF0000','#FF00FF','#00FF00','#00FFFF','#FFFF00'];
  var n = cs = parseInt(Math.random() * colors.length / 2);
  var cc = parseInt(Math.random() * colors.length / 2);
  var colorMode = parseInt(Math.random() * 2);
  var star = Math.round(Math.random()) == 1 &#63; "★" : "☆";
  this.r = 10;
  this.radius = Math.round(Math.random() * 30) + 60;
  this.num = Math.round(Math.random() * 5 + 5) * 2;
  this.angle = 180 / this.num * 2;
  for(var i=1; i<=this.num; i++){
   this.stars[i] = document.createElement("div");
   this.stars[i].innerHTML = star;
   this.stars[i].className = "star";
   if(colorMode == 1){
    this.stars[i].style.color = colors[n];
    if(++n > cs + cc)
     n = cs;
   }else{
    this.stars[i].style.color = colors[parseInt(Math.random() * colors.length)];
   }
   this.sky.appendChild(this.stars[i]);
  }
 },
 moveStars : function(){
  var self = this;
  if(this.r < this.radius){
   var p = this.step2 - parseInt(this.r / this.radius * 5);
   p = p < 1 &#63; 1 : p;
   this.r += p;
   p = parseInt(this.r / this.radius * 100);
   for(var i=1; i<=this.num; i++){
    this.stars[i].style.left = this.x - Math.round(this.r * Math.sin(Math.PI - (Math.PI / 180 * this.angle * i))) + "px";
    this.stars[i].style.top = this.y - Math.round(this.r * Math.cos(Math.PI - (Math.PI / 180 * this.angle * i))) + "px";
    this.stars[i].style.fontSize = 4 + p/10 + "px";
    this.setOpacity(this.stars[i], p);
   }
   setTimeout(function(){self.moveStars();}, this.delay);
  }else{
   setTimeout(function(){self.hideStars();}, 200 * Math.random());
  }
 },
 initBezier : function(){
  var coeff_x = [];
   var coeff_y = [];
  this.points = [];
  this.t = 0;
  this.delt = 1.0 / this.max;
  this.cur = 1;
  var a = parseInt(Math.random() * 5) * 90;
  coeff_x[0] = this.x;
  coeff_y[0] = this.y;
  for(var i=1; i<=this.num; i++){
   coeff_x[1] = this.x + Math.sin(Math.PI - (Math.PI / 180 * this.angle * i)) * this.radius/2;
   coeff_y[1] = this.y + Math.cos(Math.PI - (Math.PI / 180 * this.angle * i)) * this.radius/2;
   coeff_x[2] = this.x + Math.sin(Math.PI - (Math.PI / 180 * (a-this.angle * i))) * this.radius;
   coeff_y[2] = this.y + Math.cos(Math.PI - (Math.PI / 180 * (a-this.angle * i))) * this.radius;
   this.points[(i-1)*2] = coeff_x.slice(0);
   this.points[(i-1)*2+1] = coeff_y.slice(0);
  }
 },
 moveStars2 : function(){
  var self = this;
  if(this.cur < this.max){
   this.t += this.delt;
   this.cur++;
   p = parseInt(this.cur / this.max * 100);
   for(var i=1; i<=this.num; i++){
    this.stars[i].style.left = this.getNextPoint(this.degree, this.points[(i-1)*2], this.t) + "px";
    this.stars[i].style.top = this.getNextPoint(this.degree, this.points[(i-1)*2+1], this.t) + "px";
    this.stars[i].style.fontSize = 4 + p/10 + "px";
    this.setOpacity(this.stars[i], p);
   }
   setTimeout(function(){self.moveStars2();}, this.delay);
  }else{
   setTimeout(function(){self.hideStars();}, 200 * Math.random());
  }
 },
 hideStars : function(){
  for(var i=1; i<=this.num; i++){
   this.sky.removeChild(this.stars[i]);
   this.stars[i] = null;
   if(this.points != null){
    delete this.points[(i-1)*2];
    delete this.points[(i-1)*2+1];
   }
  }
  if(this.points){
   delete this.points;
  }
  this.points = null;
  if(this.loop){
   this.play();
  }
 },
 fire : function(){
  this.hideBall();
  this.showStars();
  var effect = parseInt(Math.random() * 2) + 1;
  switch(effect){
   case 1:
    this.moveStars();
    break;
   case 2:
    this.initBezier();
    this.moveStars2();
    break;
  }
 },
 play : function(){
  this.init();
  this.showBall();
  this.moveBall();
 }
};
window.onload = function(){
 for(var i=0; i<5; i++)
  new Fireworks(document.body, true).play();
};
</script>
</head>
<body>
</body>
</html>

Copy after login

I hope this article will be helpful to everyone in JavaScript programming.