Framesets and History

This document describes the flow of control in Mozilla when the user navigates through a session history involving a frameset.

Normal session history in the navigator is maintained as a linked list of session history structures, one for each document visited. This list, in reverse order starting at most recently visited can be seen from the Go menu in Navigator. On this level, a frameset is only a single session history structure and no matter how much navigating goes on inside the frameset, only one entry for the frameset will appear in the Go menu. In the above diagram, Docs 1-6 represent the session history structures that will be displayed in the Go menu.

However, history is usually navigated by the Forward and Back buttons. Because of special hooks from the UI to layout's frameset manager using Forward and Back navigation for the above diagram will take you in order to Doc1-2, H1-4, and Doc4-6. This can happen because layout keeps a separate linked list of session history structures for inside the frameset, and manipulates which one is presented to the user as currently being what is labeled as Doc 3 in the above diagram.

Again using the above diagram, say the user is currently at Doc 5 and navigates backwards to Doc 2 using the Back button.

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