- Go to the next page of a serialized html (The URL specified in <link rel="next"> inside page's <head>)
- Go to the previous page of a serialized html (The URL specified in <link rel="prev"> inside page's <head>)
- Go to the page above (The URL equal to current site's URL/../)
There are actually two extensions that do it, but poorly:
- Directory Up does add a icon in toolbar, but do not add an item at context menu.
- Space Advance does not add toolbar icon nor menu entry, it just adds a keybinding enabled when scrolling to the end of the page.
I think those navigation functions are so basic for browsing webpages that they should be included by default in the browser, even if need to be enabled by drag-and-droping it in the toolbar or setting it in about:config. And also, they are easy to be implemented. As for the existing add-ons, I think they add more function than the basic, they both just add keybindings and new behavior to these basic browsing functions, and they could keep existing after those functions being implemented in the browser by just setting new keybindings and features to the already existing browser functions. For example, the Space Advance add-on could just keep allowing the user to press the space bar at the end of a page to advance to the next page, since this feature is non-basic and just extends the basic feature of going to the next page.