Efecto estrellas de colores en el cursor

Hoy les traigo un tutorial con un efecto muy bonito que pueden implementar en su blog o web. Se trata de uns estrellitas de colores que caen cuando se mueve el cursos. Pueden ver los resultados en mi blog de pruebas.


Bien, para implementar este efecto, seguimos los siguientes pasos :

1.§ Vamos a Plantilla - Edición de HTML; si usamos a antigua interfaz de Blogger, vamos a Diseño - Edición de HTML.

2.§ Con ayuda de CTRL+F buscamos </head> y justo antes de éste, pegaremos el siguiente script:

✵ Ver SCRIPT [+/-]

<script type='text/javascript'>
//Cursor estrellas
// <![CDATA[
function initCursor() {
if (document.getElementById) {
var i, rats, rlef, rdow;
for (var i=0; i<sparkles; i++) {
var rats=createDiv(3, 3);
rats.style.visibility="hidden";
document.body.appendChild(tiny[i]=rats);
starv[i]=0;
tinyv[i]=0;
var rats=createDiv(5, 5);
rats.style.backgroundColor="transparent";
rats.style.visibility="hidden";
var rlef=createDiv(1, 5);
var rdow=createDiv(5, 1);
rats.appendChild(rlef);
rats.appendChild(rdow);
rlef.style.top="2px";
rlef.style.left="0px";
rdow.style.top="0px";
rdow.style.left="2px";
document.body.appendChild(star[i]=rats);
}
set_width();
sparkle();
}}

var hex=new Array("00","14","28","3C","50","64","78","8C","A0","B4","C8","DC","F0")
var r=1
var g=1
var b=1
var seq=1
var sparkles = 35;

var x=ox=400;
var y=oy=300;
var swide=800;
var shigh=600;
var sleft=sdown=0;
var tiny=new Array();
var star=new Array();
var starv=new Array();
var starx=new Array();
var stary=new Array();
var tinyx=new Array();
var tinyy=new Array();
var tinyv=new Array();

function sparkle() {
var c;
if (x!=ox || y!=oy) {
ox=x;
oy=y;
for (c=0; c<sparkles; c++) if (!starv[c]) {
star[c].style.left=(starx[c]=x)+"px";
star[c].style.top=(stary[c]=y)+"px";
star[c].style.clip="rect(0px, 5px, 5px, 0px)";
star[c].style.visibility="visible";
starv[c]=50;
break;
}
}
for (c=0; c<sparkles; c++) {
if (starv[c]) update_star(c);
if (tinyv[c]) update_tiny(c);
}
setTimeout("sparkle()", 40);
}

function update_star(i) {
if (--starv[i]==25) star[i].style.clip="rect(1px, 4px, 4px, 1px)";
if (starv[i]) {
stary[i]+=1+Math.random()*3;
if (stary[i]<shigh+sdown) {
star[i].style.top=stary[i]+"px";
starx[i]+=(i%5-2)/5;
star[i].style.left=starx[i]+"px";
}
else {
star[i].style.visibility="hidden";
starv[i]=0;
return;
}
}
else {
tinyv[i]=50;
tiny[i].style.top=(tinyy[i]=stary[i])+"px";
tiny[i].style.left=(tinyx[i]=starx[i])+"px";
tiny[i].style.width="2px";
tiny[i].style.height="2px";
star[i].style.visibility="hidden";
tiny[i].style.visibility="visible"
}
}

function update_tiny(i) {
if (--tinyv[i]==25) {
tiny[i].style.width="1px";
tiny[i].style.height="1px";
}
if (tinyv[i]) {
tinyy[i]+=1+Math.random()*3;
if (tinyy[i]<shigh+sdown) {
tiny[i].style.top=tinyy[i]+"px";
tinyx[i]+=(i%5-2)/5;
tiny[i].style.left=tinyx[i]+"px";
}
else {
tiny[i].style.visibility="hidden";
tinyv[i]=0;
return;
}
}
else tiny[i].style.visibility="hidden";
}

document.onmousemove=mouse;
function mouse(e) {
set_scroll();
y=(e)?e.pageY:event.y+sdown;
x=(e)?e.pageX:event.x+sleft;
}

function set_scroll() {
if (typeof(self.pageYOffset)=="number") {
sdown=self.pageYOffset;
sleft=self.pageXOffset;
}
else if (document.body.scrollTop || document.body.scrollLeft) {
sdown=document.body.scrollTop;
sleft=document.body.scrollLeft;
}
else if (document.documentElement && (document.documentElement.scrollTop || document.documentElement.scrollLeft)) {
sleft=document.documentElement.scrollLeft;
sdown=document.documentElement.scrollTop;
}
else {
sdown=0;
sleft=0;
}
}

window.onresize=set_width;
function set_width() {
if (typeof(self.innerWidth)=="number") {
swide=self.innerWidth;
shigh=self.innerHeight;
}
else if (document.documentElement && document.documentElement.clientWidth) {
swide=document.documentElement.clientWidth;
shigh=document.documentElement.clientHeight;
}
else if (document.body.clientWidth) {
swide=document.body.clientWidth;
shigh=document.body.clientHeight;
}
}

function createDiv(height, width) {
var div=document.createElement("div");
rainbow="#"+hex[r]+hex[g]+hex[b]
if (seq==6){
b--
if (b==0)
seq=1
}
if (seq==5){
r++
if (r==12)
seq=6
}
if (seq==4){
g--
if (g==0)
seq=5
}
if (seq==3){
b++
if (b==12)
seq=4
}
if (seq==2){
r--
if (r==0)
seq=3
}
if (seq==1){
g++
if (g==12)
seq=2
}
div.style.position="absolute";
div.style.height=height+"px";
div.style.width=width+"px";
div.style.overflow="hidden";
div.style.zIndex="10";
div.style.backgroundColor=rainbow;
return (div);
}
window.onload=function()
{
initCursor()
initImage()
startTime()
}

function initImage() {
imageId = 'menu'
image = document.getElementById(imageId);
setOpacity(image, 0);
image.style.visibility = "visible";
fadeIn(imageId,0);
}
function fadeIn(objId,opacity) {
if (document.getElementById) {
obj = document.getElementById(objId);
if (opacity <= 100) {
setOpacity(obj, opacity);
opacity += 10;
window.setTimeout("fadeIn('"+objId+"',"+opacity+")", 120);
}
}
}
function setOpacity(obj, opacity) {
opacity = (opacity == 100)?99.999:opacity;
// IE/Win
obj.style.filter = "alpha(opacity:"+opacity+")";
// Safari<1.2, Konqueror
obj.style.KHTMLOpacity = opacity/100;
// Older Mozilla and Firefox
obj.style.MozOpacity = opacity/100;
// Safari 1.2, newer Firefox and Mozilla, CSS3
obj.style.opacity = opacity/100;
}

function changeNav(id) {
document.getElementById('content').innerHTML=document.getElementById(id).innerHTML;
document.getElementById('main').innerHTML=document.getElementById('home').innerHTML;
document.getElementById('rabbit').style.top="275px"
document.getElementById('penguin').style.top="532px"
}

function hidestatus(){
window.status=""
return true
}
// ]]>
</script>

3.§ Damos click a guardar y listo!

Ver demo