function updateBlackBand()
{
    var test1 = document.documentElement.scrollHeight;
    var test2 = document.documentElement.offsetHeight
    if (test1 > test2) // all but Explorer Mac
    {
        document.getElementById("black-band").style.height = document.documentElement.scrollHeight + "px";
    }
    else // Explorer Mac;
     //would also work in Explorer 6 Strict, Mozilla and Safari
    {
        document.getElementById("black-band").style.height = document.documentElement.offsetHeight + "px";
    }
}