var bName = navigator.appName;
var bVer = parseInt(navigator.appVersion);

var NS6 = (bName == "Netscape" && bVer >=5 && bVer < 7); // alternativa check
															// su getElementById
var NS4= document.layers;
var IE4=  document.all;

// LAYER SWITCHING CODE

if (NS4) {
	layerStyleRef="layer.";
	layerRef="document.layers[";
	styleSwitch="]"; 
	layerDoc=".document.";
}
else if (IE4) {
	 layerStyleRef="layer.style.";
	 layerRef="document.all[";
	 styleSwitch="].style"; layerDoc=".";
}
else if (NS6) { 
	layerStyleRef="style.";
	layerRef="document.getElementById(";
	styleSwitch=").style"; layerDoc=".";
}	
else {
}

menutop = new Array ();
menutop[0]="menuopenpostali";
menutop[1]="menuopenbancoposta";
 menutop[2]="menuopenaltri";
 
function showLayer(layerName){
	if (NS4 || IE4 || NS6) {
		eval(layerRef+'"'+layerName+'"'+styleSwitch+'.visibility="visible"');
	}		
}
		 
function hideLayer(layerName){
	if (NS4 || IE4 || NS6) {
		eval(layerRef+'"'+layerName+'"'+styleSwitch+'.visibility="hidden"');
	}		
}
		
function hideAll () {
	for (i_loc=0; i_loc < menutop.length; i_loc ++) {
		hideLayer (menutop[i_loc]);
	}
	return false;
}