Called to run a dialog asking the user if they want to leave a page. Return false to use the default dialog implementation. Return true if the application will use a custom dialog or if the callback has been executed immediately. Custom dialogs may be either modal or modeless. If a custom dialog is used the application must executecallback once the custom dialog is dismissed.

Called when the dialog is closed.

Called to run a JavaScript dialog.

Called to cancel any pending dialogs and reset any saved dialog state. Will be called due to events like page navigation irregardless of whether any dialogs are currently pending.