function hidelayer(whichLayer) {	
	if (document.getElementById) {
	document.getElementById(whichLayer).style.visibility = "hidden";		// this is the way the standards work
	}
	else if (document.all) {
	document.all[whichlayer].style.visibility = "hidden";		// this is the way old msie versions work
	}
	else if (document.layers) {
	document.layers[whichLayer].visibility = "hidden";		// this is the way nn4 works
	}
}
	
function showlayer(whichLayer) {
	if (document.getElementById) {
	document.getElementById(whichLayer).style.visibility = "visible";		// this is the way the standards work
	}
	else if (document.all) {	
	document.all[whichlayer].style.visibility = "visible";		// this is the way old msie versions work
	}
	else if (document.layers) {
	document.layers[whichLayer].visibility = "visible";	// this is the way nn4 works
	}
}