具体代码如下：
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN""/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html xmlns="/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 ? "★" : "☆";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 ? 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>
