<Li> Alt + F4 closes the current window (or shuts down the computer if the desktop is in the foreground) on most windowing systems . </Li> <Li> Alt + Tab ↹ switches between the currently opened windows on most windowing systems, see Alt - Tab . </Li> <Li> Alt + ↵ Enter allows for a new line when Enter does another command . </Li> <P> In Microsoft Windows, holding down the Alt key while typing in numbers (often referred to as Alt codes) on the numeric keypad allows the user to type special characters not normally available on the keyboard . For example, holding down Alt while typing 0225 (Alt + 0 2 2 5) on the numeric keypad will result in á, the character at 225 in the codepage . These extended keyboard characters are useful for persons using foreign languages, mathematics, currency symbols, business use, etc . Some computers work the same if the Num Lock key is on . </P>

Where is the alt key on macbook pro