var visibleVar="null"; 
function init(){
if (navigator.appName == "Netscape") {
layerRef="document.getElementById"; 
styleSwitch=".style"; 
visibleVar="visible";
}else{
layerRef="document.all"; 
styleSwitch=".style"; 
visibleVar="visible";
}
} 
function showHideLayerSwitch(layerName){
if (eval(layerRef+'("'+layerName+'")'+styleSwitch+'.visibility == visibleVar')){ 
  hideLayer(layerName); 
}
else{ hideLayer("mnuCompany"); 
      hideLayer("mnuProducts");
      hideLayer("mnuSupport");
      hideLayer("mnuContacts");
      hideLayer("mnuGallery");
      showLayer(layerName); 
    }
} 

function showLayer(layerName){
eval(layerRef+'("'+layerName+'")'+styleSwitch+'.visibility="visible"');
} 

function hideLayer(layerName){
eval(layerRef+'("'+layerName+'")'+styleSwitch+'.visibility="hidden"');
}