An event triggered by the completion of a document load action.
For example: a web page has finished loading its initial payload, or
LibreOffice has loaded a document from disk.
An event triggered by the cancelling of a document load.
For example: during the loading of a large web page, a user may press Escape to stop loading the page.
The focused page has changed. This event is usually sent only by document readers, signaling
that the _physical page equivalent is now different.
This event does not encode which page is the new one, only that a new page is now the primary
one.
An event triggered by a reloading of a document.
For example: pressing F5, or Control + r will reload a page in a web browser.