ns = (document.layers)?true:false;
ie = (document.all)?true:false;
dom = (document.getElementById)?true:false;

function hideLayer(id){	
	if (dom) {
			// getElementByID supported.
			if (document.getElementById(id) != null)
				document.getElementById(id).style.visibility = 'hidden';
	}else if (ns){
			//Netscape 
			if (document.layers[id] != null)
				document.layers[id].visibility='hidden';
	} else if (ie){
			// Older Internet Explorer
			if (document.all[id] != null)
				document.all[id].style.visibility = 'hidden';
	}
		var obj = document.getElementById(id);
		if (obj != null)
			obj.style.display = "none";
}
function showLayer(id){	

	if (dom) {
		// getElementByID supported.
		if (document.getElementById(id) != null)
			document.getElementById(id).style.visibility = 'visible';
	}else if (ns){
		//Netscape 
		if (document.layers[id] != null)
			document.layers[id].visibility='show';
	} else if (ie){
		// Older Internet Explorer
		if (document.all[id] != null)
			document.all[id].style.visibility = 'visible';
	} 
	var obj = document.getElementById(id);
	if (obj != null)
		obj.style.display = "block";
}