heh, i know great prog found in Internet and improved by be
background coloring:

<script>
var speed=100 //SET SPEED HERE (not 0)
var r=128
var g=128
var b=128
var nr=128
var ng=128
var nb=128
var hex=new Array('0','1','2','3','4','5','6','7','8','9','A','B','C','D','E','F')
function hexa(a)
{
return hex[Math.floor(a/16)]+hex[a%16]
}
function trace()
{
if(r==nr) nr=Math.floor(Math.random*256)
if(r<nr) r++
if(r>nr) r--
if(g==nr) ng=Math.floor(Math.random*256)
if(g<nr) g++
if(g>nr) g--
if(b==nb) nb=Math.floor(Math.random*256)
if(b<nb) b++
if(b>nb) b--
document.bgColor='#'+hex(r)+hex(g)+hex(b)
setTimeout("trace()",speed)
}
trace()
</script>