Export Woocommerce product data to CSV on button click - php

Question

I have this code which is meant to take woocommerce product data (from single product page) and export it to a downloadable CSV on button click, but whenever I click the button it just refreshes the page?
<?php
// Define the function to export a WooCommerce product to CSV
function export_product_to_csv() {
// Get the product ID from the URL parameter
$product_id = $_GET['product_id'];
// Get the product data from the database
$product = wc_get_product($product_id);
// Create the CSV file
$csv_file = fopen('product.csv', 'w');
// Write the header row to the CSV file
fputcsv($csv_file, array('Product Name', 'SKU', 'Price', 'Stock Status'));
// Write the product data to the CSV file
fputcsv($csv_file, array($product->get_name(), $product->get_sku(), $product->get_price(), $product->get_stock_status()));
// Close the CSV file
fclose($csv_file);
// Download the CSV file
header('Content-Type: application/csv');
header('Content-Disposition: attachment; filename="product.csv";');
readfile('product.csv');
exit;
}
// Check if the export button was clicked
if (isset($_POST['export'])) {
export_product_to_csv();
}
?>
<!-- Add the export button to the WooCommerce product page -->
<form method="post">
<input type="hidden" name="product_id" value="<?php echo get_the_ID(); ?>">
<button type="submit" name="export">Export to CSV</button>
</form>