function toggleLayer(whichLayer)

                                    {

                                    if (document.getElementById)

                                    {

                                    var style2 = document.getElementById(whichLayer).style;

                                    style2.display = style2.display? "":"block";

                                    }

                                    else if (document.all)

                                    {

                                                            var style2 = document.all[whichLayer].style;

                                    style2.display = style2.display? "":"block";

                                    }

                                    else if (document.layers)

                                    {

                                    var style2 = document.layers[whichLayer].style;

                                    style2.display = style2.display? "":"block";

                                    }

}