function showLayer(whichLayer) {
	var elem;
	if( document.getElementById )
	{
		elem = document.getElementById( whichLayer );
		if(elem.style.display != 'block')
			elem.style.display = 'block';
	}
}

function hideLayer(whichLayer) {
	var elem;
	if( document.getElementById )
	{
		elem = document.getElementById( whichLayer );
		elem.style.display = 'none';
	}
}