var ie4=document.all&&!document.getElementById;
var ns4=document.layers;
var DOM2=document.getElementById;
var opera=(navigator.userAgent.indexOf("Opera")!=-1)?true:false
var oldlayer = "";
var timerID = 0;

if (document.layers) {
	visible = 'show';
	hidden = 'hide';
}
else if (document.all) {
	visible = 'visible';
	hidden = 'hidden';
}
else if (DOM2) {
	visible = "visible";
	hidden = "hidden";	
}

function startClock(){
	if (oldlayer != "") {
		hideLayer(oldlayer);
	}
	oldlayer = "";
}       	

function TimerRst() {
	clearTimeout(timerID); 
	timerID = setTimeout("startClock()", 2000);
}

function showLayer(layername)
{		
if (layername != "") {
	if(opera) 
		{ document.getElementById(layername).style.visibility = visible;}
	else if (DOM2)
		{ document.getElementById(layername).style.visibility = visible; }
	else if (isNav)
		{ document.layers[layername].visibility = visible;}
	else //Must be IE
		{ document.all[layername].style.visibility = visible;}
	
	clearTimeout(timerID);
	timerID = setTimeout("startClock()", 2000);
}		
	if ((oldlayer != layername) && (oldlayer != "")) {
		
		hideLayer(oldlayer);
	}
	oldlayer = layername;	
} 
 
function hideLayer(layername)
{	
	if(opera)
	{ document.getElementById(layername).style.visibility = hidden;}
	else if (DOM2)
	{ document.getElementById(layername).style.visibility = hidden;}
	else if (isNav)
	{ document.layers[layername].visibility = hidden;	}
	else //Must be IE	
	{ 	document.all[layername].style.visibility = hidden;}
}