Нагуглил вам рабочий код с аяксом
/**
* Add quantity field on the shop page.
*/
function ace_shop_page_add_quantity_field() {
/** @var WC_Product $product */
$product = wc_get_product( get_the_ID() );
if ( ! $product->is_sold_individually() && 'variable' != $product->get_type() && $product->is_purchasable() ) {
woocommerce_quantity_input( array( 'min_value' => 1, 'max_value' => $product->backorders_allowed() ? '' : $product->get_stock_quantity() ) );
}
}
add_action( 'woocommerce_after_shop_loop_item', 'ace_shop_page_add_quantity_field', 12 );
/**
* Add required JavaScript.
*/
function ace_shop_page_quantity_add_to_cart_handler() {
wc_enqueue_js( '
$(".woocommerce .products").on("click", ".quantity input", function() {
return false;
});
$(".woocommerce .products").on("change input", ".quantity .qty", function() {
var add_to_cart_button = $(this).parents( ".product" ).find(".add_to_cart_button");
// For AJAX add-to-cart actions
add_to_cart_button.attr("data-quantity", $(this).val());
// For non-AJAX add-to-cart actions
add_to_cart_button.attr("href", "?add-to-cart=" + add_to_cart_button.attr("data-product_id") + "&quantity=" + $(this).val());
});
// Trigger on Enter press
$(".woocommerce .products").on("keypress", ".quantity .qty", function(e) {
if ((e.which||e.keyCode) === 13) {
$( this ).parents(".product").find(".add_to_cart_button").trigger("click");
}
});
' );
}
add_action( 'init', 'ace_shop_page_quantity_add_to_cart_handler' );