// Toggles layer to display or not
function toggleLayer(whichLayer) {
	var el;
	el = getElement(whichLayer);
	for (var i=0, el; el = getElement(arguments[i]); i++) {
		el.style.display = (el.style.display != 'block' ? 'block' : 'none' );
	}
}

// Get element by ID
function getElement(whichLayer)
{
	return (document.getElementById) ? document.getElementById( whichLayer ) : // Standards compliant
										(document.all) ? document.all[whichLayer] : // old IE
											document.layers ? document.layers[whichLayer] : // NN 4
												whichLayer; // Never called
}