jquery on input add commas

// add commas to number
let numberWithCommas = (x) => {
  return x.toString().replace(/\B(?=(\d{3})+(?!\d))/g, ",");
}

// ES5
function numberWithCommas(x) {
  return x.toString().replace(/\B(?=(\d{3})+(?!\d))/g, ",");
}