html/lab4/task2/cards.js - master - Coderdev/web-static-labs

html/lab4/task2/cards.js
65 строк2 KB
Coderdev
12 май 2026, 12:37
12 май 2026, 12:37d8ecd0f
'use strict';
const $ = (id) => document.getElementById(id);
const digitsOnly = (s) => s.replace(/\D+/g, '');
function detectBrand(num) {
    if (num.startsWith('220')) return 'mir';
    if (num.startsWith('35')) return 'jcb';
    const veBins = ['4026', '4175', '4508', '4844', '4913', '4917'];
    if (veBins.some(bin => num.startsWith(bin))) return 'visael';
    if (num.startsWith('50') || num.startsWith('56') || num.startsWith('57') || num.startsWith('58') || num.startsWith('59') || num.startsWith('6')) return 'maestro';
    if (num.startsWith('5')) return 'mc';
    if (num.startsWith('4')) return 'visa';
    return null;
}
function luhnCheck(num) {
    let sum = 0;
    let shouldDouble = false;
    for (let i = num.length - 1; i >= 0; i--) {
        let digit = parseInt(num.charAt(i));
        if (shouldDouble) {
            digit *= 2;
            if (digit > 9) digit -= 9;
        }
        sum += digit;
        shouldDouble = !shouldDouble;
    }
    return (sum % 10) === 0;
}
function formatCardNumber(num) {
    const matches = num.match(/.{1,4}/g);
    if (!matches) return num;
    return matches.join(' ');
}
function clearHighlight() {
    const active = document.querySelector('#cards img.hl');
    if (active) active.classList.remove('hl');
}
document.addEventListener('DOMContentLoaded', () => {
    const input = $('cardNumber');
    const button = $('cardCheck');
    const out = $('result');
    input.addEventListener('input', () => {
        clearHighlight();
        out.textContent = '';
    });
    button.addEventListener('click', () => {
        clearHighlight();
        const raw = String(input.value);
        const num = digitsOnly(raw);
        if (num.length < 13 || num.length > 19) {
            out.textContent = 'Неверно введен номер карты';
            return;
        }
        if (!luhnCheck(num)) {
            out.textContent = 'Ошибка контрольной суммы';
            return;
        }
        const brandId = detectBrand(num);
        if (brandId) {
            const img = $(brandId);
            if (img) img.classList.add('hl');
        }
        input.value = formatCardNumber(num);
        out.textContent = 'Номер карты корректен';
    });
});