code: function onError (e) {
              switch (e.target.errorCode) {
              case 12:
                  console.log('Error - Attempt to open db with a lower version than the ' +
                          'current one.');
                  break;
              default:
                  console.log('errorCode: ' + e.target.errorCode);
              }
  
              console.log(e, e.code, e.message);
          }
docs: Global error handler. Errors bubble from request, to transaction, to db.