button.addEventListener('click', (event) => {
event.preventDefault();
fetch(`https://example.com/api.php?part=${partId}`)
    .then(function (response) {
        return response.json();
    })
    .then(function (jsonRes) {
        console.log(JSON.stringify(jsonRes));
        if (jsonRes.part.partFound == true) {
            console.log('Found! Processing...');
            // REMOVE preventDefault() and process
        } else {
            console.log('Not found! Aborting...', partId);
        }
    });