Using a sweet alert with preventDefault() I have an event on a form submit.

I set preventDefault() to stop the form submitting then pop a sweetalert with a confirm callback.  If they decide to go ahead is POSTS the form to Drupal.

The issue is that it does not hit the form_submit method but redirects to the same page with a GET request.  If I simply return true from the jQuery submit event it works.

If they confirm I have tried 

form.off('submit').submit()


but it still does not work.

Can anybody help as it is driving me crazy?
I solved this, just in case anybody else comes across it.

Drupal uses a variable called $op == "Update", which is an attribute on the Submit .  When you use preventDefault() this is removed from the Form Data.

The solution is to add this to the sweetalert callback function when they confirm to delete or whatever your use case is.

          formE.off('submit');
          var input = $("&lt;input&gt;").attr("type", "hidden").attr("name", "op").val("Update");
          formE.append(input);
          formE.submit();


Drupal now gets that so hits the form_submit function.