var bName = navigator.appName;
var bVer = parseInt(navigator.appVersion);
var NN = (bName == "Netscape" && bVer >= 4);
var IE = (bName == "Microsoft Internet Explorer" && bVer >= 4);
var ver4 = ( NN || IE );

if (ver4) 
{
   if (NN) {
      layerRef="document.layers";
      styleSwitch="";
   }
   else {
      layerRef="document.all";
      styleSwitch=".style";
   }
}

function showLayer(n) 
{
   if (ver4) {
      for(i = 0; i < 9; i++) {
         if (i == n) {
            eval(layerRef + '["menu' + n + '"]' + styleSwitch + '.visibility="visible"');
         }
         else {
            eval(layerRef + '["menu' + i + '"]' + styleSwitch + '.visibility="hidden"'); 
         }
      }
   }   
}

function hideLayer(n)
{
   if (ver4) {
      eval(layerRef+'["menu'+n+'"]'+styleSwitch+'.visibility="hidden"');
   }   
}