code: function maybeUploadOnSubmit(formEl) {
          var nativeSubmit = formEl.submit;
  
          // Intercept and squelch submit events.
          qq(formEl).attach("submit", function(event) {
              event = event || window.event;
  
              if (event.preventDefault) {
                  event.preventDefault();
              }
              else {
                  event.returnValue = false;
              }
  
              validateForm(formEl, nativeSubmit) && startUpload();
          });
  
          // The form's `submit()` function may be called instead (i.e. via jQuery.submit()).
          // Intercept that too.
          formEl.submit = function() {
              validateForm(formEl, nativeSubmit) && startUpload();
          };
      }
docs: Intercept form submit attempts, unless the integrator has told us not to do this.