if (navigator.appName == "Netscape"){//1
	var isNav = true;
	styleSwitch="";
	insideLayer="document.background.document";
}//1
else{
	layer_call="document.all";
	styleSwitch=".style";
}
var current_layer = "blank";

function show_layer(layer){//1
	if(isNav){//2
		eval(insideLayer+'.'+layer+'.visibility="show"');
	}//2
	else{
		eval(layer_call+'["'+layer+'"]'+styleSwitch+'.visibility="visible"');
	}//2
}//1

function hide_layer(layer){//1
	if(isNav){//2
		eval(insideLayer+'.'+layer+'.visibility="hide"');
	}//2
	else{//2
		eval(layer_call+'["'+layer+'"]'+styleSwitch+'.visibility="hidden"');
	}//2
}//1

function clear_tag(){
	if(isNav){//2
		eval(insideLayer+'.'+current_layer+'.visibility="hide"');
	}//2
	else{//2
		eval(layer_call+'["'+current_layer+'"]'+styleSwitch+'.visibility="hidden"');
	}//2
}

function roll_over(layer_name){//1
	hide_layer(current_layer);
	show_layer(layer_name);
	current_layer=layer_name;
}//1