function update_price(product_category, is_renewal, amount, period_in_years, price_element) {
	// Safety, to prevent displaying the old price when the AJAX request takes unusual long.
	price_element.innerHTML = '';
	new Ajax.Updater(price_element, '/ajax/get_price.php', { method: 'get', parameters: { product_category: product_category, is_renewal: is_renewal, period_in_years: period_in_years, amount: amount } });
}

function update_transaction_overview(container_element) {
	new Ajax.Updater(container_element, '/ajax/get_transaction_overview.php', { method: 'get' });
}