function AddToShoppingCart(product_id)
{
    var url=null;

    if(product_id==null || product_id<1)
        url="/tShowBasket.aspx";
    else{
            url="/tShowBasket.aspx?add_product="+product_id+"&reference_url="+escape(window.location.href);
    }
    var popup=window.open(url,"langlang_shoppingcart");
    popup.focus()
}