An estimate of what fraction of the current navigation has been loaded.
- iOS 8.0+
- macOS 10.10+
This value ranges from
1 based on the total number of bytes expected to be received, including the main document and all of its potential subresources. After navigation loading completes, the
estimated remains at
1 until a new navigation starts, at which point the
estimated is reset to
WKWeb class is key-value observing (KVO) compliant for this property.