var ns4=document.layers;
var ie4=document.all;
var ns6=document.getElementById&&!document.all;

//Hide and Show Layers
var layerRef 
var styleSwitch

if (ns4){
	   layerRef = 'document.layers[';
	   styleSwitch = ']';
	} else if(ie4) {
	   layerRef = 'document.all[';
	   styleSwitch = '].style';
	} else if(ns6) {
	   layerRef = 'document.getElementById(';	
	   styleSwitch = ').style';	
	}

/* Hide Layer */
function hideLayer(layerID){
	eval(layerRef + '"' + layerID + '"' + styleSwitch + '.visibility="hidden"');
}

/* Show Layer */
function showLayer(layerID){
	eval(layerRef + '"' + layerID + '"' + styleSwitch + '.visibility="visible"');
}

	if (document.images) {
	
	//create navigation image objects
	WhatOn = new Image();      
    WhatOn.src = "../Images/gtpGesWh_on.gif";
	
	WhatOff = new Image();      
    WhatOff.src = "../Images/gtpGesWh_off.gif";
	
	HistoryOn = new Image();      
    HistoryOn.src = "../Images/gtpGesHist_on.gif";
	
	HistoryOff = new Image();      
    HistoryOff.src = "../Images/gtpGesHist_off.gif";
	
	AboutOn = new Image();      
    AboutOn.src = "../Images/gtpGTPAb_on.gif";
	
	AboutOff = new Image();      
    AboutOff.src = "../Images/gtpGTPAb_off.gif";
	
	TPSOn = new Image();      
    TPSOn.src = "../Images/gtpGTPTPS_on.gif";
	
	TPSOff = new Image();      
    TPSOff.src = "../Images/gtpGTPTPS_off.gif";
	
	CoachOff = new Image();
	CoachOff.src = "../Images/gtpCoach_off.gif";

	CoachOn = new Image();
	CoachOn.src = "../Images/gtpCoach_on.gif";
	
	DirOn = new Image();      
    DirOn.src = "../Images/gtpGTPDir_on.gif";
	
	DirOff = new Image();      
    DirOff.src = "../Images/gtpGTPDir_off.gif";
	
	ArtOn = new Image();      
    ArtOn.src = "../Images/gtpGTPArt_on.gif";
	
	ArtOff = new Image();      
    ArtOff.src = "../Images/gtpGTPArt_off.gif";
	
	EcalOn = new Image();      
    EcalOn.src = "../Images/gtpCmEcal_on.gif";
	
	EcalOff = new Image();      
    EcalOff.src = "../Images/gtpCmEcal_off.gif";
	
	AcalOn = new Image();      
    AcalOn.src = "../Images/gtpCmAcal_on.gif";
	
	AcalOff = new Image();      
    AcalOff.src = "../Images/gtpCmAcal_off.gif";
	
	CcalOn = new Image();      
    CcalOn.src = "../Images/gtpCmCcal_on.gif";
	
	CcalOff = new Image();      
    CcalOff.src = "../Images/gtpCmCcal_off.gif";
	
	NewsOn = new Image();      
    NewsOn.src = "../Images/gtpCmNews_on.gif";
	
	NewsOff = new Image();      
    NewsOff.src = "../Images/gtpCmNews_off.gif";
	
	CdirOn = new Image();      
    CdirOn.src = "../Images/gtpCmDir_on.gif";
	
	CdirOff = new Image();      
    CdirOff.src = "../Images/gtpCmDir_off.gif";
	
	HomeOn = new Image();      
    HomeOn.src = "../Images/gtpHome_on.gif";
	
	HomeOff = new Image();      
    HomeOff.src = "../Images/gtpHome_off.gif";
	
}

// navigation image activator
function imgOn(imgName) {
        if (document.images)
        {
            document[imgName].src = eval(imgName + "On.src");
			//document["preview"].src = eval(imgName + "Pre.src");
        }
}

// navigation image deactivator
function imgOff(imgName) {
        if (document.images)
        {
            document[imgName].src = eval(imgName + "Off.src");
			//document["preview"].src = "images/trans.gif";
        }
}