The locale read-only property of the IDBIndex interface returns the locale of the index (for example en-US, or pl) if it had a locale value specified upon its creation (see createIndex()'s optionalParameters.) Note that this property always returns the current locale being used in this index, in other words, it never returns "auto".
A key range can be a single value or a range with upper and lower bounds or endpoints. If the key range has both upper and lower bounds, then it is bounded; if it has no bounds, it is unbounded. A bounded key range can either be open (the endpoints are excluded) or closed (the endpoints are included). To retrieve all keys within a certain range, you can use the following code constructs:
To determine if the add operation has completed successfully, listen for the transaction’s complete event in addition to the IDBObjectStore.add request’s success event, because the transaction may still fail after the success event fires. In other words, the success event is only triggered when the transaction has been successfully queued.