ReadonlylowerThe lower read-only property of the IDBKeyRange interface returns the lower bound of the key range.
ReadonlylowerThe lowerOpen read-only property of the IDBKeyRange interface returns a boolean indicating whether the lower-bound value is included in the key range.
ReadonlyupperThe upper read-only property of the IDBKeyRange interface returns the upper bound of the key range.
ReadonlyupperThe upperOpen read-only property of the IDBKeyRange interface returns a boolean indicating whether the upper-bound value is included in the key range.
The
IDBKeyRangeinterface of the IndexedDB API represents a continuous interval over some data type that is used for keys. Records can be retrieved from IDBObjectStore and IDBIndex objects using keys or a range of keys. You can limit the range using lower and upper bounds. For example, you can iterate over all values of a key in the value range A–Z.MDN Reference