function doRound(x, places) {
	var result = Math.round(x * Math.pow(10, places)) / Math.pow(10, places);
	return result.toFixed(places);
}

function getTaxRate() {
	return 17.5;
}

function updateRetailNet() {
	var taxRate = getTaxRate();
	var netValue = document.forms["product_form"].fixed_price.value;

	if (taxRate > 0) {
		netValue = netValue / ((taxRate / 100) + 1);
	}
	document.getElementById('fixed_price_net').innerHTML = doRound(netValue, 2);
}

function updateOfferNet() {
 	var taxRate = getTaxRate();
	var netValue = document.forms["product_form"].offer_price.value;

	if (taxRate > 0) {
		netValue = netValue / ((taxRate / 100) + 1);
	}
	document.getElementById('offer_price_net').innerHTML = doRound(netValue, 2);
}