Alternatively known as Control 8 and C-8, Ctrl+8 is a shortcut key most often used to switch to the eigth tab in a browser or another program with tab support.
How to use the Ctrl+8 shortcut key
The "8" used with this shortcut is the "8" at the top of the keyboard and not on the numeric keypad.
Ctrl+8 in Microsoft Excel
If no outline exists, you'll be prompted if you'd like to create an outline when pressing Ctrl+8.
Using Ctrl+8 in an Internet browser
If you only have seven tabs open, pressing Ctrl+8 does nothing.
Related keyboard shortcuts
Below are links to related keyboard key and keyboard shortcut pages.