This is based on the code from 03l54rd1n3. It is an updated version which receives an input parameter for the brutto yearly value and calculates the netto value based on brutto-netto-rechner.info.
see this repo for usage. You need to define the request properties in code, yet you can execute the script by using node from a command line, making sure you pass the brutto-yearly-income as parameter.
node .\index.js 40000