function updateTotals() {

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

	var total = 0;
	
	if(adults > 0) {
		total +=  (adults * 300);
		document.getElementById('formAdultsSubtotal').value = '$' + (adults * 300);
	}

	if(adults == 2 && document.getElementById('formCouple').checked) {
		total = total -150;
		document.getElementById('formCoupleSubtotal').value = '-150';
	} else {
		document.getElementById('formCouple').checked = false;
		document.getElementById('formCoupleSubtotal').value = '';
	}
	
	if(total > 0) {
		document.getElementById('formTotal').value = '$' + total;
	}
	
}

window.onload = updateTotals;