Intercept and modify DOM before page is displayed to user

Question

I\'m trying to create a Firefox addon (using addon SDK) that will modify how the page is displayed, mostly as a training/learning exercise.

For some tasks (like augm

Answer 1

If you want to get into it before any script has executed there are document observers here: https://developer.mozilla.org/en-US/docs/Observer_Notifications#Documents such as content-document-global-created