Ile wplacono poprzez X na siepomaga.pl

siepomaga.js

let amount = parseFloat(document.querySelector(".amount").innerText.replace(" ", "").replace(",", "."))
let payments = document.querySelectorAll(".sp-payment-amount");

let paymentSum = 0;
for (let payment of payments) {
  const paymentFloat = parseFloat(payment.innerText);
  if (isNaN(paymentFloat))
    continue;
  paymentSum += paymentFloat;
}

let amountMissing = amount - paymentSum;
console.log("Wpłacono poprzez X:", amountMissing);