function toggleLayer(whichLayer)
{
        if (document.getElementById)
        {
                // this is the way the standards work
                var style2 = document.getElementById(whichLayer).style;
                style2.display = style2.display? "":"block";
        }
        else if (document.all)
        {
                // this is the way old msie versions work
                var style2 = document.all[whichLayer].style;
                style2.display = style2.display? "":"block";
        }
        else if (document.layers)
        {
                // this is the way nn4 works
                var style2 = document.layers[whichLayer].style;
                style2.display = style2.display? "":"block";
        }
}