title: jQuery - Prevent submit inside promise with post ajax validation
body: <p>We trying to stop form submit after an validation returned from an post. The call is inside a promise and after a confirm dialog.</p>
  
  <p>After hours breaking my mind I couldn't make it work.</p>
  
  <pre><code>var $form = $('#frmBoleto');
  
  $form.submit(function(e){
      var modo = $('input[name="modo"]:checked').val();
  
      if (modo == 'naoimprime'){
          // Send post
          $.when( $.post($form.attr('action') + '?verifica', $form.serialize())).then(function( d ){
              if (d &amp;&amp; d.exists){
                  var answer = window.confirm('You sure?');
  
                  if (!answer){
                      e.preventDefault();
                      e.stopImmediatePropagation();
                      e.stopPropagation();
                  }
              }
          });
      }
  });
  </code></pre>
  
  <p>Form is always submited, why?</p>