Firefox keyboard shortcut to switch search engines in search bar
- Click at the icon
- Select "Manage Search Engines…"
- Select the search engine you want to set a shortcut for
- Click on "Edit keyword…"
- Give a shortcut, e.g. "g" for Google
Now you can type into the address bar the chosen search shortcut followed by what you like to search. Example: g weather berne.
To switch to the address bar with the keyboard, use the shortcut Ctrl+L. You could also open a new tab (Ctrl+T), because it sets the focus to the address bar automatically.
By the way: this works for nearly all search fields on any website. Just right-click on a search field and select "Add a keyword for this search…" (don't know the actual English translation). Instead of adding this search to the search widget, Firefox saves it as a bookmark.
There is a shortcut for exactly this task: from the search bar, press control + Down(Next)/Up(Previous).
In newer versions of Firefox, the shortcut you are looking for is Alt + Up/Down.