Crazy bug where just mobile Safari/Chrome when submitting on a page with a long URL/query string prints out some AJAX rather than posting as expected

Our problem is in the first line of that form: Our action has got a bit too much packed into it.

<form data-nid="15294" action="/classes?field_discipline_tid=All&amp;level=All&amp;class-type=All&amp;instructor=15051&amp;field_age_group_tid=All&amp;field_class_day_of_week_value=All&amp;field_class_time_of_day_value=All&amp;keyword=" method="post" id="uc-product-add-to-cart-form-15294" accept-charset="UTF-8" class="uc-out-stock-processed">

<input type="hidden" name="form_build_id" value="form-5LMsf5MdT7sDjG2lwg1VAB9ef9qbobnurTG3E6S7-8A">
<input type="hidden" name="form_id" value="uc_product_add_to_cart_form_15294">

</form>

Simply form-altering the action to /classes or url("classes") didn’t work any better than changing the HTML directly to that with inspector: We end up on that page, with nothing in the cart.

Same with changing the action to cart.

It needs to be submitted to self it seems?

https://www.drupal.org/forum/support/theme-development/2008-09-04/form-theming-how-do-i-set-formaction

Ah no you can just put a ‘#’ there.

This post, though not about that, happened to be doing that in the example and so helped me realize that simple option:

https://stackoverflow.com/questions/9940580/drupal-form-action