Keyboard mnemonic
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A keyboard mnemonic (also referred to as a keyboard indicator, and sometimes, less properly, as a keyboard shortcut) is a key that can be pressed to perform some action normally done by another input device. Most keyboard mnemonics are visible in some way at the time they can be used (which sets them apart from keyboard shortcuts, which more often need to be memorized). For example, it is common for one character of menu labels and menu items to be underlined. When in the appropriate keyboard context, the user simply strikes the underlined character to jump directly to that part of the interface. (Entering the context for mnemonics often involves typing or holding a modifier key, such as Alt).
[edit] Efficiency and Accessibility
Keyboard mnemonics can be significant time-savers, and offer a method of executing commands that can be sped up beyond what a mouse may offer. They are also extremely useful for users who have difficulty manipulating a mouse precisely enough to use small widgets.
For example, one could learn, by watching for the underlined letters, that the mnemonic path to "Page Setup" under the File menu is F, then U. If "Page Setup" is a frequently used command, the user will eventually type Alt,F,U very quickly and without even looking at the File menu's contents.
Contrasted with the mouse method of first moving the cursor (which may be anywhere) to the File menu (which may not always be in the same place on the screen), then scanning the File menu for "Page Setup" (which, thanks to new productivity features in programs such as Microsoft Office may not always be visible), the benefits are obvious. Mnemonics also have an advantage over keyboard shortcuts in that they are (with a few exceptions) documented within the interface of the program.
[edit] Some Examples and Exceptions
In Microsoft Windows, the key for switching to the mnemonic context is Alt. This key can either be pressed or held, though in some cases it must be released after the first mnemonic is activated if the activated item is a menu. Some lesser-known mnemonics not shown by the interface are:
- (spacebar): Shows the window menu for the focused window.
- - (hyphen): In a multiple document interface, this will show the menu for the currently focused child window.
- In Windows versions 2000 and later, there is an option under the Display control panel (enabled by default) that hides mnemonic indicators until the Alt key is pressed. This is presumably because a majority of users did not know what all the single underlined characters meant, and considered them aesthetically displeasing.