function net_change() {
var vat_rate = document.getElementById('vat_rate');
var net_price = document.getElementById('net_price');
var gross_price = document.getElementById('gross_price');
var tax_amount = document.getElementById('tax_amount');
gross_price.value = net_price.value *(1+(vat_rate.value/100));
tax_amount.value = gross_price.value - net_price.value;
}
 
function gross_change() {
var vat_rate = document.getElementById('vat_rate');
var net_price = document.getElementById('net_price');
var gross_price = document.getElementById('gross_price');
var tax_amount = document.getElementById('tax_amount');
net_price.value = gross_price.value - (gross_price.value * (vat_rate.value/100));
tax_amount.value = gross_price.value - net_price.value;
}
 
function amount_change() {
var vat_rate = document.getElementById('vat_rate');
var net_price = document.getElementById('net_price');
var gross_price = document.getElementById('gross_price');
var tax_amount = document.getElementById('tax_amount');
net_price.value = ((tax_amount.value / vat_rate.value)*100);
gross_price.value = Number(net_price.value) + Number(tax_amount.value);;
}
 
 
function vat_change() {
var vat_rate = document.getElementById('vat_rate');
var net_price = document.getElementById('net_price');
var gross_price = document.getElementById('gross_price');
var tax_amount = document.getElementById('tax_amount');
net_price.value = gross_price.value - (gross_price.value * (vat_rate.value/100));
gross_price.value = net_price.value *(1+(vat_rate.value/100));
 
}
 
 
// Добавляет слушателя событий для таблицы
var vat_rate = document.getElementById('vat_rate');
var net_price = document.getElementById('net_price');
var gross_price = document.getElementById('gross_price');
var tax_amount = document.getElementById('tax_amount');
 
vat_rate.addEventListener("input", vat_change, false);
net_price.addEventListener("input", net_change, false);
gross_price.addEventListener("input", gross_change, false);
tax_amount.addEventListener("input", amount_change, false);