I believe angular will do the right thing and prevent the default submit action if the 'action' attribute isn't visible in the <form> tag. However, I believe the html generated here results in an empty (but existing) action attribute:
    <form method="post" data-ng-submit="submit()" class="simple_form message ng-scope ng-pristine ng-valid" action="" accept-charset="UTF-8">
 Can we completely disable the 'action' attribute for simple_forms?