i get a problem to set the callback function before indexeddb add transaction

```
os = ...the object store (IDBObjectStore) object assigned here
os.onsuccess = function(){alert('dont mess with Messi')}
os.add({name:'Lionel Messi',team:'FC Barcelona',position:'striker',number:10});

```

the entry was successfully added to the object store, but the function on onsuccess event won't fired. there's another event called onerror. should i use it instead? i dont think so

don't ask me for 'can you give the error part?' because there's no error at all