function layer(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";
     }
}