[webkit-help] When webkit construct a complete dom tree

[bai]

Hi,
 I want to traverse over the dom tree to hide  advertisements before
webkit renders to the screen,so it's better to traverse more earlier
more better.
in DocumentLoader::finishedLoading function,i cannot get a partial dom
tree, but in DocumentLoader::updateLoading, after test all the loading
have stoped,it's too later, all the picture has been rendered to the
screen.
Could any one  tell me the right position to hide the advetisements?
Thanks.