scroll bar

A vertical bar on the right side of a window or a horizontal bar at the bottom of a window that is used to move the window contents up and down or left and right. The bar contains a box with square or rounded corners, which together look like an elevator in a shaft. The box is called a "thumb" or "elevator," and when dragged with the mouse, the window contents move correspondingly. When the bar is clicked above or below the thumb, the contents are moved one page at a time. The arrows are clicked to move one line at a time.

Scroll Bars
Clicking in the bar or dragging the thumb moves the contents within the window. The Mac example (right) shows an optional variation that places both scroll arrows in the same vicinity to lessen mouse movement when switching directions.

scroll bar [′skrōl ‚bär]

(computer science)

A horizontal or vertical bar that contains a box that is clicked and dragged up, down, left, or right in order to scroll the screen.

(graphics)

scroll bar - A widget found in graphical user interfaces and used to show and control ("scroll") which portion of a document is currently visible in a window. A window may have a horizontal or, most often, vertical scroll bar or both.

A vertical scroll bar is a narrow strip drawn up the side of the window containing a "bubble" whose position in the scroll bar represents the position of the visible part within the whole document. By dragging the bubble with the mouse the user can scroll the view over the entire document. Arrow buttons are usually provided at the end(s) of the scroll bar to allow the window to be scrolled by a small amount, e.g. one line of text, in either direction by clicking them with the mouse. Some programs provide a second pair of buttons for scrolling a page at a time or some other unit. Clicking on the scroll bar outside the bubble will either, depending on the particular WIMP, move the bubble to that point or move it some amount (typically a screenful) in that direction.

Different WIMP systems define different standards for whether scroll bars appear on the left or right, top or bottom of the window, and for their behaviour.

To reduce mouse movement, the up and down scroll buttons should either be next to each other at one end of the scroll bar (as in NEXTSTEP) or should reverse their effect when clicked with the right-hand mouse button (as in the X Window System and RISC OS). The fraction of the scroll bar filled by the bubble should indicate the fraction of the document visible in the window.