document.addEventListener('DOMContentLoaded', () => {
    fetch('get.php')
        .then(r => r.json())
        .then(data => {
            const table = document.getElementById('tab');
            table.innerHTML = `<tr><th>Kurs</th><th>Czas trwania</th><th>Cena</th>` +
            data.map($row => `<tr><td>${$row.nazwa}</td><td>${$row.czas_trwania}</td><td>${$row.cena}</td></tr>`).join('');
        });
});