function updateTotals() {

	var adults = document.getElementById('formAdults').value;

	var total = 0;
	
	if(adults > 0) {
		total +=  (adults * 200);
		document.getElementById('formAdultsSubtotal').value = '$' + (adults * 200);
	}
	
	if(total > 0) {
		document.getElementById('formTotal').value = '$' + total;
	}
	
}

window.onload = updateTotals;