Correct way to set an empty page?

[jdx]

I have a dialog with a web-control in, when I hide the dialog videos carry on playing which is bad if there is audio. Is there a dedicated API method to clear the page, or do I need to load "about:blank" or another special URL?

[jonmmorgan]

I think loading about:blank is a fairly "official" way to do it. Certainly in the wxWebConnect source it loads about:blank when the wxWebControl is created.

[jdx]

Is there a way to avoid this page being in my page history so forward/back don't include it?

[jerry_mouse]

Is there a way to avoid this page being in my page history so forward/back don't include it?

To monitor and manage history session entries is quite simple and straight forward.
Firstly, you have to implement the interface nsISHistoryListener, then create an instant of it and add to the session history listeners of each browser window by using nsISHistory::addSHistoryListener(nsISHistoryListener aListener)
The handle to the session history object can be obtained from nsIWebNavigation (which then can be obtained from nsIWebBrowser).