firework.js

// <![CDATA[
var bits=80; // how many bits
var speed=33; // how fast - smaller is faster
var bangs=5; // how many can be launched simultaneously (note that using too many can slow the script down)
var colours=new Array("#03f", "#f03", "#0e0", "#93f", "#0cf", "#f93", "#f0c");
//                     blue    red     green   purple  cyan    orange  pink

/****************************
*      Fireworks Effect     *
*(c)2004-14 mf2fm web-design*
*  http://www.mf2fm.com/rv  *
* DON'T EDIT BELOW THIS BOX *
****************************/
var bangheight=new Array();
var intensity=new Array();
var colour=new Array();
var Xpos=new Array();
var Ypos=new Array();
var dX=new Array();
var dY=new Array();
var stars=new Array();
var decay=new Array();
var swide=1000;
var shigh=600;
var boddie;

if (typeof('addRVLoadEvent')!='function') function addRVLoadEvent(funky) {
  var oldonload=window.onload;
  if (typeof(oldonload)!='function') window.onload=funky;
  else window.onload=function() {
    if (oldonload) oldonload();
    funky();
  }
}

addRVLoadEvent(light_blue_touchpaper);

function light_blue_touchpaper() { if (document.getElementById) {
  var i;
  boddie=document.createElement("div");
  boddie.style.position="fixed";
  boddie.style.top="0px";
  boddie.style.left="0px";
  boddie.style.overflow="visible";
  boddie.style.zIndex = '9999';
  boddie.style.width="1px";
  boddie.style.height="1px";
  boddie.style.backgroundColor="transparent";
  document.body.appendChild(boddie);
  set_width();
  for (i=0; i<bangs; i++) {
    write_fire(i);
    launch(i);
    setInterval('stepthrough('+i+')', speed);
  }
}}

function write_fire(N) {
  var i, rlef, rdow;
  stars[N+'r']=createDiv('|', 12);
  boddie.appendChild(stars[N+'r']);
  for (i=bits*N; i<bits+bits*N; i++) {
    stars[i]=createDiv('*', 13);
    boddie.appendChild(stars[i]);
  }
}

function createDiv(char, size) {
  var div=document.createElement("div");
  div.style.font=size+"px monospace";
  div.style.position="absolute";
  div.style.zIndex = '9999';
  div.style.backgroundColor="transparent";
  div.appendChild(document.createTextNode(char));
  return (div);
}

function launch(N) {
  colour[N]=Math.floor(Math.random()*colours.length);
  Xpos[N+"r"]=swide*0.5;
  Ypos[N+"r"]=shigh-5;
  bangheight[N]=Math.round((0.5+Math.random())*shigh*0.4);
  dX[N+"r"]=(Math.random()-0.5)*swide/bangheight[N];
  if (dX[N+"r"]>1.25) stars[N+"r"].firstChild.nodeValue="/";
  else if (dX[N+"r"]<-1.25) stars[N+"r"].firstChild.nodeValue="\\";
  else stars[N+"r"].firstChild.nodeValue="|";
  stars[N+"r"].style.color=colours[colour[N]];
}

function bang(N) {
  var i, Z, A=0;
  for (i=bits*N; i<bits+bits*N; i++) {
    Z=stars[i].style;
    Z.left=Xpos[i]+"px";
    Z.top=Ypos[i]+"px";
    if (decay[i]) decay[i]--;
    else A++;
    if (decay[i]==15) Z.fontSize="7px";
    else if (decay[i]==7) Z.fontSize="2px";
    else if (decay[i]==1) Z.visibility="hidden";
    if (decay[i]>1 && Math.random()<.1) {
       Z.visibility="hidden";
       setTimeout('stars['+i+'].style.visibility="visible"', speed-1);
    }
    Xpos[i]+=dX[i];
    Ypos[i]+=(dY[i]+=1.25/intensity[N]);

  }
  if (A!=bits) setTimeout("bang("+N+")", speed);
}

function stepthrough(N) {
  var i, M, Z;
  var oldx=Xpos[N+"r"];
  var oldy=Ypos[N+"r"];
  Xpos[N+"r"]+=dX[N+"r"];
  Ypos[N+"r"]-=4;
  if (Ypos[N+"r"]<bangheight[N]) {
    M=Math.floor(Math.random()*3*colours.length);
    intensity[N]=5+Math.random()*4;
    for (i=N*bits; i<bits+bits*N; i++) {
      Xpos[i]=Xpos[N+"r"];
      Ypos[i]=Ypos[N+"r"];
      dY[i]=(Math.random()-0.5)*intensity[N];
      dX[i]=(Math.random()-0.5)*(intensity[N]-Math.abs(dY[i]))*1.25;
      decay[i]=16+Math.floor(Math.random()*16);
      Z=stars[i];
      if (M<colours.length) Z.style.color=colours[i%2?colour[N]:M];
      else if (M<2*colours.length) Z.style.color=colours[colour[N]];
      else Z.style.color=colours[i%colours.length];
      Z.style.fontSize="13px";
      Z.style.visibility="visible";
    }
    bang(N);
    launch(N);
  }
  stars[N+"r"].style.left=oldx+"px";
  stars[N+"r"].style.top=oldy+"px";
}

window.onresize=set_width;
function set_width() {
  var sw_min=999999;
  var sh_min=999999;
  if (document.documentElement && document.documentElement.clientWidth) {
    if (document.documentElement.clientWidth>0) sw_min=document.documentElement.clientWidth;
    if (document.documentElement.clientHeight>0) sh_min=document.documentElement.clientHeight;
  }
  if (typeof(self.innerWidth)!="undefined" && self.innerWidth) {
    if (self.innerWidth>0 && self.innerWidth<sw_min) sw_min=self.innerWidth;
    if (self.innerHeight>0 && self.innerHeight<sh_min) sh_min=self.innerHeight;
  }
  if (document.body.clientWidth) {
    if (document.body.clientWidth>0 && document.body.clientWidth<sw_min) sw_min=document.body.clientWidth;
    if (document.body.clientHeight>0 && document.body.clientHeight<sh_min) sh_min=document.body.clientHeight;
  }
  if (sw_min==999999 || sh_min==999999) {
    sw_min=800;
    sh_min=600;
  }
  swide=sw_min;
  shigh=sh_min;
}
// ]]>