Random background color changer

<!-- this script got from my-javacodes.blogspot.com-Coded by: Morad Hasan -->

<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 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>

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