{% load i18n l10n pcart_catalog %}
<form class="__action--ajax-submit" action="{% add_to_cart_url %}" method="post" data-post-signal="update-cart">
    {% csrf_token %}
    <input type="hidden" name="item-id" value="{{product.id}}">
    <input type="hidden" name="next" value="{{product.get_absolute_url}}">
    <input type="hidden" name="item-type" value="{{product.type}}">
    <input type="hidden" name="price" value="{{product.price|unlocalize}}">
    <input type="hidden" name="weight" value="{{product.weight|unlocalize}}">
    <input type="number" name="quantity" value="{{quantity|default:1}}">
    <button class="btn btn-success" type="submit" name="add-to-cart">{% trans "Add to cart" %}</button>
</form>