Opencart 1.5.4 addToCart（）第一次页面显示功能不起作用

I am currently working on a project in Open Cart 1.5.4. I slighty moved the cart into another div without any problems. The thing is on new computers and first time they enter the site it´s not possible for the customer to add a product to cart. If they go into another page and then back it works just fine. The javascript file is loaded properly without any problems.

Hope this explanation explains the problem or bug pretty good.

Thanks in advance.

JAVASCRIPT

function addToCart(product_id, quantity) {
    quantity = typeof(quantity) != 'undefined' ? quantity : 1;

    $.ajax({
        url: 'index.php?route=checkout/cart/add',
        type: 'post',
        data: 'product_id=' + product_id + '&quantity=' + quantity,
        dataType: 'json',
        success: function(json) {
            $('.success, .warning, .attention, .information, .error').remove();

            if (json['redirect']) {
                location = json['redirect'];
            }

            if (json['success']) {
                //$('#notification').html('<div class="success" style="display: none;">' + json['success'] + '<img src="catalog/view/theme/default/image/close.png" alt="" class="close" /></div>');

                $('.success').fadeIn('slow');
                try {
                    $('#cart-total').html(json['total']);
                }
                catch(err) {
                    console.log(err.message());
                }

                $('html, body').animate({ scrollTop: 0 }, 'slow');

                $(".heading").animate({backgroundColor: "#FFFFFF"}, 'slow');

                $(".cart_arrow").attr("style", "display: block;");

                $(".heading").animate({backgroundColor: "#585858"}, 'slow');

            }   
        }
    });
}

Found the cause of the problem. When Open Cart is installed and domain is about to be choosen, you can choose www or non-www. Depends on the one you choose the other wont work. So the solution to the problem htaccess redirect for this one from non-www to www adress

RewriteCond %{HTTP_HOST} ^domain.com$ [NC]
RewriteRule ^(.*) http://www.domain.com/$1 [R=301,L]

RewriteBase /
RewriteRule ^sitemap.xml$ index.php?route=feed/google_sitemap [L]
RewriteRule ^googlebase.xml$ index.php?route=feed/google_base [L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{REQUEST_URI} !.*\.(ico|gif|jpg|jpeg|png|js|css)
RewriteRule ^([^?]*) index.php?_route_=$1 [L,QSA]

The redirect has to be over RewriteBase /

Thanks and I hope this helps in the future for anyone nedded this kind of support

change

url: 'index.php?route=checkout/cart/add',

to

url: $('base').attr('href') + 'index.php?route=checkout/cart/add',