Here is another firework effect made with simple javascript.
To add this to your page or blog, just copy and paste this code to your page's head section.
or if you wish to add to blog, then Select add javascript /html option in layout section and paste this script, then save.
<script type="text/javascript"> var stopafter = 0; var firestop = []; var fire = []; var stdDOM = document.getElementById; var nsDOM = ((navigator.appName.indexOf('Netscape') != -1) && (parseInt(navigator.appVersion) ==4)); function pageWidth() {return window.innerWidth != null? window.innerWidth: document.body != null? document.body.clientWidth:700;}function pageHeight() {return window.innerHeight != null? window.innerHeight: document.body != null? document.body.clientHeight:500;} function posLeft() {return typeof window.pageXOffset != 'undefined' ? window.pageXOffset:document.documentElement.scrollLeft? document.documentElement.scrollLeft:document.body.scrollLeft? document.body.scrollLeft:0;} function posTop() {return typeof window.pageYOffset != 'undefined' ? window.pageYOffset:document.documentElement.scrollTop? document.documentElement.scrollTop: document.body.scrollTop?document.body.scrollTop:0;} var hD="0123456789ABCDEF"; function d2h(d) {return hD.substr(d>>>4,1)+hD.substr(d&15,1);} layernum=0; piece = function(parent) {this.elem = null; if(nsDOM) {if(parent == null) this.elem=new Layer(1); else {this.elem=new Layer(1,parent.elem); this.style.visibility = "inherit";} this.parent = parent; this.style = this.elem;} else if (stdDOM) {if(parent == null) this.parent=document.body; else this.parent=parent.elem; this.elem = document.createElement('div'); var xName = "xLayer" + layernum++; this.elem.setAttribute('id', xName); elemc = document.createTextNode('.'); this.elem.appendChild(elemc); this.parent.appendChild(this.elem); this.style = this.elem.style;document.getElementById(xName).style.lineHeight = '3px'; document.getElementById(xName).style.color = '#fff'; document.getElementById(xName).style.position = 'absolute';} window[this.elem.id]=this; this.ay = .1; this.type = 0;}; piece.prototype.moveTo = function(x,y) {if(nsDOM) this.elem.moveTo(x,y); else {this.style.left = x+"px"; this.style.top = y+"px";}}; piece.prototype.setC = function(colour) {if(nsDOM) this.elem.bgColor = colour; else this.style.backgroundColor = colour==null?'transparent':colour; };  piece.prototype.fire = function(sx, sy, fw) {var a = Math.random() * Math.PI * 2; switch (fw) {case 1: var s = Math.random() * 2; break; case 2: var s = 2; break; case 3: var s = (Math.PI * 2) - a - Math.random(); break; case 4: var s =  a - Math.random(); break; default: var s = Math.random() * 2; if(Math.random() >.6) s = 1.5;} this.dx = s*Math.sin(a); this.dy = s*Math.cos(a) - 2; this.x = sx; this.y = sy; this.moveTo(sx, sy);}; piece.prototype.sCol = function(hex,hex2,cl) {switch (cl) {case 1: this.setC("#" + hex + hex2 + "00"); break; case 2: this.setC("#00" + hex + "00"); break; case 3: this.setC("#00" + hex + hex2); break; case 4: this.setC("#" + hex + "0000"); break; case 5: this.setC("#" + hex + hex + "00"); break; case 6: this.setC("#" + hex + hex + hex); break; case 7: this.setC("#" + hex2 + hex + "00"); break; default: this.setC("#" + hex + hex2 + hex);}}; piece.prototype.animate = function(step,cl) {var colour = (step > 25) ?  Math.random()*(380-(step*5)) : 255-(step*4); var hex = d2h(colour-112); if (colour < 112) hex = d2h(colour); this.sCol(d2h(colour),hex,cl); this.dy += this.ay; this.x += this.dx; this.y += this.dy; this.moveTo(this.x, this.y);}; fo = function(numst) {this.id = "fo"+fo.count++;this.sp = new Array(); for(i=0 ; i<numst; i++) {this.sp[i]=new piece(); if(nsDOM){this.sp[i].style.clip.top =0; this.sp[i].style.clip.left = 0; this.sp[i].style.clip.bottom = 3; this.sp[i].style.clip.right = 3;} else this.sp[i].style.clip="rect("+0+" "+3+" "+3+" "+0+")"; this.sp[i].style.visibility = "visible";} this.step = 0; window[this.id]=this; fire.push(this); firestop.push(setInterval("window."+this.id+".animate()", 15));}; fo.count = 0; fo.prototype.animate = function() {if(this.step > 55) this.step = 0; if(this.step == 0) {var x = posLeft() + 50 + (Math.random()*(pageWidth() - 200)); var y = posTop() + 50 + (Math.random()*(pageHeight() - 250)); var fw = Math.floor(Math.random() * 5); this.cl = Math.floor(Math.random() * 8); for(i=0 ; i<this.sp.length ; i++)this.sp[i].fire(x, y, fw);} this.step++; for(i=0 ; i<this.sp.length ; i++) this.sp[i].animate(this.step,this.cl);}; function stopfire() {for(var i = firestop.length - 1; i >= 0; i--) {clearInterval(firestop[i]); for (var j = fire[i].sp.length - 1; j >= 0; j--) {fire[i].sp[j].style.visibility = "hidden";}}} function fireworks() {new fo(50);setTimeout('new fo(50)',750);if (stopafter > 0) {setTimeout('stopfire()',stopafter * 60000);}} window.onload=fireworks; </script>