ในการ attach ไฟล์ หากไม่มีการ Attach file ให้แสดงเป็น null

if(isset($_FILES["fileUpload"]) && $_FILES["fileUpload"]["error"] === UPLOAD_ERR_OK) {
    $fileInfo = pathinfo($_FILES["fileUpload"]["name"]);
    $fileType = $fileInfo['extension'];
    $newName = date('YmdHis') . '.' . $fileType;

    if(move_uploaded_file($_FILES["fileUpload"]["tmp_name"], "content/" . $newName)) {
        echo "<center>File upload completed successfully.</center><br>";
    } else {
        echo "<center>Failed to move uploaded file.</center><br>";
    }
} else {
    echo "<center>No file was uploaded or an error occurred.</center><br>";
}