// this array consists of the id attributes of the divs we wish to alternate between
var divs_to_fade = new Array('box-1', 'box-2', 'box-3', 'box-4','box-5', 'box-6', 'box-7', 'box-8','box-9', 'box-10', 'box-11', 'box-12','box-13', 'box-14', 'box-15', 'box-16','box-17', 'box-18', 'box-19', 'box-20');

// the starting index in the above array.  It should be set to the value of the div which doesn't have the CSS Display property set to "none"
var i = 0;

// the number of milliseconds between swaps.  Default is five seconds.
var wait = 3500;

// the function that performs the fade
function swapFade() {
    Effect.Fade(divs_to_fade[i], { duration:1.5, from:1.0, to:0.0 });
    i++;
    if (i == 20) i = 0;
    Effect.Appear(divs_to_fade[i], { duration:1.5, from:0.0, to:1.0 });
}

// the onload event handler that starts the fading.
function startPage() {
    setInterval('swapFade()',wait);
}