Prevents Drupal from throwing alert()s when AJAX is interrupted.

drupal-ajax.js

preventAlerts: function () {
  //Copy drupal's original error function for later use if you want
  Drupal.ajax.prototype.original_error = Drupal.ajax.prototype.error;
  Drupal.ajax.prototype.error = function (response, uri) {
    // This should catch the "terminated abnormally" error
    if (response.readyState == 0 || response.readyState == 4) {
      console.log(response);
    }
    else {
      this.original_error(response, uri);
    }
  }
}