Removes all key/value pairs from the Web Storage area.
HRESULT retVal = object.clear();
This method has no parameters.
If this method succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code.
There are no standards that apply here.
Session storage is cleared immediately. Local storage key/value pairs are removed from memory, and disk storage quota is updated.
Build date: 11/17/2013