History
Originally, (on early writers dating back to the late 19th century) the "bar" was literally a metal bar running across the full width of the keyboard (or even wider, and even surrounding it) that triggered the carriage advance without also firing any of the typebars towards the platen. Later examples gradually shrank and developed into their current more ergonomic form as a wide, centrally located but otherwise apparently normal "key", as typewriter (and computer) keyboards began to incorporate additional function keys and were more deliberately "styled". Although it varies by keyboard type, the space bar usually lies between the Alt keys (or Command keys on Macintosh keyboards) and below the letter keys: C, V, B, N and M on a standard QWERTY keyboard. In some keyboards, both physical and specially virtual ones, the symbol is used to label the space bar. Some early typewriter and particularly computer keyboards used a different method of inserting spaces, typically a smaller, less distinct "space" key which was also often set in a less central position, e.g. the Hansen Writing Ball, Hammond typewriters or the Sinclair ZX Spectrum and Jupiter Ace ranges. The earliest known example,Other uses
Depending on the operating system, the space bar used with a modifier key such as the control key may have functions such as resizing or closing the current window, half-spacing, or even backspacing. On web browsers, the space bar usually allows the user to page down or to page up when the space bar is used with the Shift key. In many programs for playback of linear media (such as videos or music), the space bar is used for pausing and resuming playback, or for manually advancing through text. In video games where the playable character can move and jump, the default key to jump is usually the space bar. This is usually used along with theReferences
{{keyboard keys Computer keys Whitespace