Changing background color effect

Am gasit pe net un cod care modifica culoarea backgroundului automat la un anumit interval de timp

Cod:

<script>

// Select fade-effect below:
// Set 1 if the background may fade from dark to medium
// Set 2 if the background may fade from light to medium
// Set 3 if the background may fade from very dark to very light
// Set 4 if the background may fade from light to very light
// Set 5 if the background may fade from dark to very dark
var fade_effect=3

// What type of gradient should be applied Internet Explorer 5x or higher?
// Set "none" or "horizontal" or "vertical"
var gradient_effect="horizontal"

// Speed higher=slower
var speed=60

///////////////////////////////////////////////////////////////////////////
// CONFIGURATION ENDS HERE
///////////////////////////////////////////////////////////////////////////

var browserinfos=navigator.userAgent
var ie4=document.all&&!document.getElementById
var ie5=document.all&&document.getElementById&&!browserinfos.match(/Opera/)
var ns4=document.layers
var ns6=document.getElementById&&!document.all
var opera=browserinfos.match(/Opera/) 
var browserok=ie4||ie5||ns4||ns6||opera

if (fade_effect==1) {
   var darkmax=1
   var lightmax=127
}
if (fade_effect==2) {
   var darkmax=127
   var lightmax=254
}
if (fade_effect==3) {
   var darkmax=1
   var lightmax=254
}
if (fade_effect==4) {
   var darkmax=190
   var lightmax=254
}
if (fade_effect==5) {
   var darkmax=1
   var lightmax=80
}
var hexc = new Array('0','1','2','3','4','5','6','7','8','9','A','B','C','D','E','F')

var newred
var newgreen
var newblue
var oldred
var oldgreen
var oldblue

var redcol_1
var redcol_2
var greencol_1
var greencol_2
var bluecol_1
var bluecol_2
var oldcolor
var newcolor
var firsttime=true
 
var stepred=1
var stepgreen=1
var stepblue=1

function setrandomcolor() {
   var range=(lightmax-darkmax)
   if (firsttime) {
      newred=Math.ceil(range*Math.random())+darkmax
      newgreen=Math.ceil(range*Math.random())+darkmax
      newblue=Math.ceil(range*Math.random())+darkmax
      firsttime=false
   }
   
   oldred=Math.ceil(range*Math.random())+darkmax
   oldgreen=Math.ceil(range*Math.random())+darkmax
   oldblue=Math.ceil(range*Math.random())+darkmax
   
   stepred=newred-oldred
   if (oldred>newred) {stepred=1}
   else if (oldred<newred) {stepred=-1}
   else {stepred=0}
   
   stepgreen=newgreen-oldgreen
   if (oldgreen>newgreen) {stepgreen=1}
   else if (oldgreen<newgreen) {stepgreen=-1}
   else {stepgreen=0}
   
   stepblue=newblue-oldblue
   if (oldblue>newblue) {stepblue=1}
   else if (oldblue<newblue) {stepblue=-1}
   else {stepblue=0}
   fadebg()
}

function fadebg() {
   if (newred==oldred) {stepred=0}
   if (newgreen==oldgreen) {stepgreen=0}
   if (newblue==oldblue) {stepblue=0}
   newred+=stepred
   newgreen+=stepgreen
   newblue+=stepblue
   
   if (stepred!=0 || stepgreen!=0 || stepblue!=0) {
         redcol_1 = hexc[Math.floor(newred/16)];
       redcol_2 = hexc[newred%16];
       greencol_1 = hexc[Math.floor(newgreen/16)];
         greencol_2 = hexc[newgreen%16];
        bluecol_1 = hexc[Math.floor(newblue/16)];
         bluecol_2 = hexc[newblue%16];
        newcolor="#"+redcol_1+redcol_2+greencol_1+greencol_2+bluecol_1+bluecol_2
      if (ie5 && gradient_effect!="none") {
         if (gradient_effect=="horizontal") {gradient_effect=1}
         if (gradient_effect=="vertical") {gradient_effect=0}
            greencol_1 = hexc[Math.floor(newred/16)];
          greencol_2 = hexc[newred%16];
          bluecol_1 = hexc[Math.floor(newgreen/16)];
            bluecol_2 = hexc[newgreen%16];
           redcol_1 = hexc[Math.floor(newblue/16)];
            redcol_2 = hexc[newblue%16];
         var newcolorCompl="#"+redcol_1+redcol_2+greencol_1+greencol_2+bluecol_1+bluecol_2
         document.body.style.filter=
"progid:DXImageTransform.Microsoft.Gradient(startColorstr="+newcolorCompl+", endColorstr="+newcolor+" GradientType="+gradient_effect+")"
      }
      else {
           document.bgColor=newcolor
      }
      var timer=setTimeout("fadebg()",speed);
    }
     else {
        clearTimeout(timer)
      newred=oldred
      newgreen=oldgreen
      newblue=oldblue
      oldcolor=newcolor
      setrandomcolor()
     }
}

if (browserok) {
   window.onload=setrandomcolor
}
</script>


Puteti modifica acest 3 din var fade_effect=3 cu orice numar de la 1 la 5.
- daca puneti 1 culorile se vor modifica de la inchis spre medium
- daca puneti 2 culorile se vor modifica de la deschis spre medium
- daca puneti 3 culorile se vor modifica de la foarte inchis spre foarte deschis
- daca puneti 4 culorile se vor modifica de la deschis spre foarte deschis
- daca puneti 5 culorile se vor modifica de la inchis spre foarte inchis



Mai puteti modifica si var speed=60. Cu cat numarul este mai mic cu atat culorile se vor schimba mai repede