The inverse box in a scroll bar. The position of the scroll box in the scroll bar indicates the position of what's in the window relative to the entire document.
The box contained in the scroll bar. The scroll box shows the relative position of the information displayed on the monitor as compared to the entire document. That is, if the scroll box is in the middle of the scroll bar, the current text shown is in about the middle of the document. The scroll box can be dragged by the mouse to make an image or text document move up/down or left/right.
A small box located in the scroll bar that shows where the visible window is located in relation to the entire document, menu, or list. You can click and drag the scroll box to make other portions of the document, menu, or list visible.