dont add Product to cart when we click on ADD TO CART

Question

By Default , ADD TO CART will do 2 things.

1)Add Item to cart

2)Create new row in sales_flat_quote_item_option Table in Value column.

But We want to remove first feature & want to keep only 2nd one when we click on ADD TO CART.

current code :

<?php $buttonTitle = Mage::helper('core')->quoteEscape($this->__('Add to Cart')); ?>

<button onclick="productAddToCartForm.submit(this)"><span><span><?php echo $buttonTitle ?></span></span></button>

I tried replacing onclick="setLocation('<?php echo $this->getAddToCartUrl($_product) ?>')" but still Product is adding to cart when we click on ADD TO CART.

But we dont want to add Product to cart when we click on ADD TO CART

Edit : skin/frontend/base/default/js/msrp.js

var cartButton = $('map-popup-button');
            if (typeof this.cartLink != 'undefined') {
                if (typeof productAddToCartForm == 'undefined' || this.notUseForm) {
                    Catalog.Map.setGotoView(cartButton, this.cartLink);
                    productAddToCartForm = $('product_addtocart_form_from_popup');
                } else {
                    if (this.qty) {
                        productAddToCartForm.qty = this.qty;
                    }
                    cartButton.stopObserving('click');
                    cartButton.href = this.cartLink;
                    Event.observe(cartButton, 'click', function(event) {
                        productAddToCartForm.action = this.href;
                        productAddToCartForm.submit(this);
                    });
                }
                productAddToCartForm.action = this.cartLink;
                var productField = $('map-popup-product-id');
                productField.value = this.product_id;
                $(cartButton).show();
                $$('.additional-addtocart-box').invoke('show');
            } else {
                $(cartButton).hide();
                $$('.additional-addtocart-box').invoke('hide');
            }

Answer 1

You can rewrite controllers function responsible for add product to cart
magento1\app\code\core\Mage\Checkout\controllers\CartController.php :: addAction