document.addEventListener('DOMContentLoaded', async() => {
    const res = await fetch('get.php');
    const data = await res.json();

    const t = document.getElementById('tab');
     t.innerHTML = t.rows[0]?.outerHTML + data.map(r =>
        `<tr><td>${r.nazwa}</td><td>${r.czas_trwania}</td><td>${r.cena}</td></tr>`
    ).join("");
})