[While supported in pre-release versions, this property is obsolete and error should be used instead. Applications using this property should be updated accordingly.]
If a request fails, this property contains a code indicating the reason for the failure.
This property is read-only.
errcode = object.errorCode
A value corresponding to an error code supported by the operation associated with the request.
This method can throw the following DOMException exceptions:
The request is not complete.
The value of this property is not set until after the readyState property is set to "IDBRequest.DONE". .