This topic describes navigating among panes as it applies to the Accessibility API.
If the window is not a frame window, the NEXT and PREVIOUS calls return S_FALSE and an empty VARIANT. This return indicates that there was no error and that there are no more siblings in that direction. FIRSTCHILD and LASTCHILD calls return the one and only child of the window. That child is the pane (BODY or FRAMESET). If the window belongs to a frame, the NEXT and PREVIOUS calls return the frame sibling in that direction. If there is no sibling in that direction, the call returns S_FALSE and an empty VARIANT.