Here is the fade in code:

<SCRIPT LANGUAGE="JavaScript">
function makearray(n) {
    this.length = n;
    for(var i = 1; i <= n; i++)
        this[i] = 0;
    return this;
}

hexa = new makearray(16);
for(var i = 0; i < 10; i++)
    hexa[i] = i;
hexa[10]="a"; hexa[11]="b"; hexa[12]="c";
hexa[13]="d"; hexa[14]="e"; hexa[15]="f";

function hex(i) {
    if (i < 0)
        return "00";
    else if (i > 255)
        return "ff";
    else
        return "" + hexa[Math.floor(i/16)] + hexa[i%16];
}

function setbgColor(r, g, b) {
    var hr = hex(r); var hg = hex(g); var hb = hex(b);
    document.bgColor = "#"+hr+hg+hb;
}

function fade(sr, sg, sb, er, eg, eb, step) {
    for(var i = 0; i <= step; i++) {
        setbgColor(
        Math.floor(sr * ((step-i)/step) + er * (i/step)),
        Math.floor(sg * ((step-i)/step) + eg * (i/step)),
        Math.floor(sb * ((step-i)/step) + eb * (i/step)));
    }
}

/* Usage:
 *   fade(inr,ing,inb, outr,outg,outb, step);
 * example.
 *   fade(0,0,0, 255,255,255, 255);
 * fade from black to white with very slow speed.
 *   fade(255,0,0, 0,0,255, 50);
 *   fade(0xff,0x00,0x00, 0x00,0x00,0xff, 50); // same as above
 * fade from red to blue with fast speed.
 * step 2 is very fast and step 255 is very slow.
 */

function fadein() {
    fade(255,255,255,0,0,0,128);
}

function fadeout() {
    fade(0,0,0,255,255,255,16);
}

fadein();

</SCRIPT>