var currentCard = 1;

function toggleLayer(whichLayer) {
	var style2 = $(whichLayer).style;
	style2.display = style2.display? "":"block";
}

function nextCard() {
	if (currentCard > 3) 
		return;
	
	currentCard++;
	for (var i = 1; i < 4; i++) {
		if (i == currentCard)
			$('card' + i).show();
		else
			$('card' + i).hide();
	}
}