hy does my PHP file upload script fail on large files

Question

Im building a file upload feature in PHP and it works fine for small files, but anything over ~2–3 MB fails silently or gives a blank page.  

Here’s a simplified version of my code:

```php
if (isset($_FILES['file'])) {
    move_uploaded_file($_FILES['file']['tmp_name'], "uploads/" . $_FILES['file']['name']);
    echo "Upload done!";
}