Custom add to cart button to add multiple product into cart with quantity :woocommerce

You need to pass quantity in query string like:

?post_type=product&add-to-cart=100&quantity=2

I have modify you code

 <script>
    jQuery('#buy').click(function(e) {
     e.preventDefault(); 
    var myStringArray = [<?php echo $p_id; ?>];
    var arrayLength = myStringArray.length;
    for (var i = 0; i < arrayLength; i++) {
     addToCart(myStringArray[i],2);
    }

    return true;

    //window.location.href = "http://seoexpertiser.ca/glassful/cart/";
    });

    function addToCart(p_id,qu) {
     $.get('/glassful/?post_type=product&add-to-cart=' + p_id +'&quantity='+qu, function() {
     // success
    $(".show_success").show();
     });

    }
    </script>

I think this will solve your problem.

Please check this link , This is works for me :)

WooCommerce: Allow adding multiple products to the cart via the add-to-cart query string

functions.php

function woocommerce_maybe_add_multiple_products_to_cart() {
    // Make sure WC is installed, and add-to-cart qauery arg exists, and contains at least one comma.
    if ( ! class_exists( 'WC_Form_Handler' ) || empty( $_REQUEST['add-to-cart'] ) || false === strpos( $_REQUEST['add-to-cart'], ',' ) ) {
        return;
    }

    // Remove WooCommerce's hook, as it's useless (doesn't handle multiple products).
    remove_action( 'wp_loaded', array( 'WC_Form_Handler', 'add_to_cart_action' ), 20 );

    $product_ids = explode( ',', $_REQUEST['add-to-cart'] );
    $count       = count( $product_ids );
    $number      = 0;

    foreach ( $product_ids as $product_id ) {
        if ( ++$number === $count ) {
            // Ok, final item, let's send it back to woocommerce's add_to_cart_action method for handling.
            $_REQUEST['add-to-cart'] = $product_id;

            return WC_Form_Handler::add_to_cart_action();
        }

        $product_id        = apply_filters( 'woocommerce_add_to_cart_product_id', absint( $product_id ) );
        $was_added_to_cart = false;
        $adding_to_cart    = wc_get_product( $product_id );

        if ( ! $adding_to_cart ) {
            continue;
        }

        $add_to_cart_handler = apply_filters( 'woocommerce_add_to_cart_handler', $adding_to_cart->product_type, $adding_to_cart );

        /*
         * Sorry.. if you want non-simple products, you're on your own.
         *
         * Related: WooCommerce has set the following methods as private:
         * WC_Form_Handler::add_to_cart_handler_variable(),
         * WC_Form_Handler::add_to_cart_handler_grouped(),
         * WC_Form_Handler::add_to_cart_handler_simple()
         *
         * Why you gotta be like that WooCommerce?
         */
        if ( 'simple' !== $add_to_cart_handler ) {
            continue;
        }

        // For now, quantity applies to all products.. This could be changed easily enough, but I didn't need this feature.
        $quantity          = empty( $_REQUEST['quantity'] ) ? 1 : wc_stock_amount( $_REQUEST['quantity'] );
        $passed_validation = apply_filters( 'woocommerce_add_to_cart_validation', true, $product_id, $quantity );

        if ( $passed_validation && false !== WC()->cart->add_to_cart( $product_id, $quantity ) ) {
            wc_add_to_cart_message( array( $product_id => $quantity ), true );
        }
    }
}

// Fire before the WC_Form_Handler::add_to_cart_action callback.
add_action( 'wp_loaded', 'woocommerce_maybe_add_multiple_products_to_cart', 15 );

and you can use for your link.

$product_ids = implode( ',', array( 1, 2, 55 ) );
$url = esc_url_raw( add_query_arg( 'add-to-cart', $product_ids, wc_get_checkout_url() ) );

Thanks !

Save products id in array and make ajax request

 jQuery("#addSelected").click(function() {  var arrayLength =
 arrayOfAddedProducts.length;   jQuery.ajax({
         type: "POST",
         url: ajaxurl,
         data: {action : 'add_item_from_cart','getIDtoAdd' : arrayOfAddedProducts},
         success: function (res) {
            wc_load_all_products();
         }
     }); });

function.php

function add_item_from_cart() {
   foreach ($_POST['getIDtoAdd'] as $productId) {
      WC()->cart->add_to_cart( intval($productId), 1, 0, array(), array() );
    // WC()->cart->add_to_cart( $product_id = 0, $quantity = 1, $variation_id = 0, $variation = array(), $cart_item_data = array() );
   }
}

add_action('wp_ajax_add_item_from_cart', 'add_item_from_cart');
add_action('wp_ajax_nopriv_add_item_from_cart', 'add_item_from_cart');