var oldcat = null

function alPulsarCategoria(o) { 	
	if (oldcat) switchDisplay(document.getElementById("sub"+oldcat.id));
	if (oldcat==o) {
		oldcat = null;
	} else {
		switchDisplay(document.getElementById("sub"+o.id));
		oldcat = o;
	}
}

function switchDisplay(o) {
	if (o && o.style) {
		if (o.style.display == "none") o.style.display = ""; else o.style.display = "none";
	}
}