NS4 = (document.layers) ? 1 : 0;
IE4 = (document.all) ? 1 : 0;
NS6 = (document.getElementById) ? 1 : 0;
ver4 = (NS4 || IE4) ? 1 : 0;

function showHide(layername) {
	if (NS4) {
		if (document.layers[layername].display == "none")
			document.layers[layername].display = "block";
		else {
			document.layers[layername].display = "none";
		}
	}
	else if (NS6) {
		if (document.getElementById(layername).style.display == "none")
			document.getElementById(layername).style.display = "block";
		else {
			document.getElementById(layername).style.display = "none";
		}
	}
	else {
		if (document.all[layername].style.display == "none")
			document.all[layername].style.display = "block";
		else {
			document.all[layername].style.display = "none";
		}
	}
}