var isIE, isNN4, isNN6;

/*
** cross browser
** nn4: document.layers['layerInQuestion'].visibility = 'visible/hidden'
** nn6: document.getElementById('layerInQuestion').visibility =
'visible/hidden'
** ie: document.all['layerInQuestion'].style.visibility = 'visible/hidden'
*/

if (navigator.appName == "Netscape") {
	var baseVersion = navigator.appVersion.substring(0,1);
	if ((baseVersion == "5") || (baseVersion == "6")) {
		isNN6 = true;
	}
	else {
		isNN4 = true;
	}
}
else {
	isIE = true;
}

function showLyr(layerName) {
	if (isNN4) {
		document.layers[layerName].visibility = 'visible';		
		document.layers['welcome'].visibility = 'hidden';
	}
	else if (isIE) {
		document.all[layerName].style.visibility = 'visible';
		document.all['welcome'].style.visibility = 'hidden';
	}
	else {
		document.getElementById(layerName).style.visibility = 'visible';
		document.getElementById('welcome').style.visibility = 'hidden';
	}
}

function hideLyr(layerName) {
	if (isNN4) {
		document.layers[layerName].visibility = 'hidden';	
		document.layers['welcome'].visibility = 'visible';
	}
	else if (isIE) {
		document.all[layerName].style.visibility = 'hidden';
		document.all['welcome'].style.visibility = 'visible';
	}
	else {
		document.getElementById(layerName).style.visibility = 'hidden';
		document.getElementById('welcome').style.visibility = 'visible';
	}
}