codice:
<html>
<head>
<style type="text/css">
h1 {text-align:center}
</style>
<title></title>
<h1 align="center"><script
language="JavaScript">
<!-- Hide the script from old browsers --
function MakeArray(n){
this.length=n;
for(var i=1; i<=n; i++) this[i]=i-1;
return this
}
hex=new MakeArray(16);
hex[11]="A"; hex[12]="B"; hex[13]="C"; hex[14]="D"; hex[15]="E"; hex[16]="F";
function ToHex(x){ // Changes a int to hex (in the range 0 to 255)
var high=x/16;
var s=high+""; //1
s=s.substring(0,2); //2 the combination of these are the same as the trunc function
high=parseInt(s,10); //3
var left=hex[high+1]; // left part of the hex-value
var low=x-high*16; // calculate the rest of the values
s=low+""; //1
s=s.substring(0,2); //2 the combination of these are the same as the trunc function
low=parseInt(s,10); //3
var right=hex[low+1]; // right part of the hex-value
var string=left+""+right; // add the high and low together
return string;
}
function rainbow(text){
text=text.substring(3,text.length-4); // gets rid of the HTML-comment-tags
color_d1=255; // any value in 'begin' 0 to 255
mul=color_d1/text.length;
for(i=0;i < text.length;i++){
color_d1=255*Math.sin(i/(text.length/3)); // some other things you can try >> "=255-mul*i" to fade out, "=mul*i" to fade in, or try "255*Math.sin(i/(text.length/3))"
color_h1=ToHex(color_d1);
color_d2=mul*i;
color_h2=ToHex(color_d2);
document.write("<FONT COLOR='#FF"+color_h1+color_h2+"'>"+text.substring(i,i+1)+'</FONT>');
}
}
// --End Hiding Here -->
</script></font></h1>
</head><body bgcolor="black">
<h1 align="top"><font size="5" face="Verdana">
<script>
<!--
{rainbow("--> Vi auguriamo una buona visita al sito! <!--");}
//-->
</script> </h1>
</head>
<body bgcolor="black">
</body>
</html>
togli le parti in rosso e aggiungi le blu 
ciao