An application must move the scroll area in a scroll bar. Although the user requests scrolling in a scroll bar, the scroll bar does not automatically update the position of the scroll area. Instead, the request is passed to the parent window, which must scroll through the data and update the position of the scroll box. An application uses the SetScrollInfo function to update the position of the scroll area. Otherwise, the SetScrollPos function is used. Because the movement of the scroll area is controlled, the application can move the scroll area in the best way with the scrolling data. The advantage of using a standard scroll bar is that the system creates the scroll bar and automatically adjusts its size and position. However, the default scroll bars are sometimes too restrictive. For example, suppose you want to divide a customer space into quadrants and use a separate set of scroll bars to control the contents of each quadrant. You cannot use standard scroll bars because you can only create one set of scroll bars for a given window. Use the scroll bar controls instead, as you can add as many as you want to a window. There is often only one scroll bar in a window, which is the vertical scroll bar that allows you to scroll up and down in a window.
Many programs automatically wrap text in a window when you resize the window or zoom the document. Programs with a fixed window size or no line break enabled display a horizontal scroll bar when the window is resized. For these programs, there would be two scroll bars, a horizontal scroll bar, and a vertical scroll bar. Since the advent of scroll mice using a scroll wheel for vertical and horizontal scrolling, the scroll bar is used less and less in desktop applications. Plus, content on tablets and smartphones scrolls with your fingers, and a scroll bar has never been a natural part of the user interface. See Scroll the mouse. In 1980, Interlisp had a scroll bar that appeared on the left side of the window as the cursor moved to the left. The shaded thumb of the bar indicated the percentage of visible content and was controlled by the middle button. The left button scrolled up to move the selected location to the top of the window, and the right button scrolled down to move the top edge of the window to the selected location.  The specific capability and methods required to customize the appearance and function of scroll bars may vary greatly depending on the operating system or software application you want to customize. A common way to change the appearance of the scroll bar on web pages is to use CSS directives to change the colors of the scroll bar.
These are non-standard and are only supported by Microsoft Internet Explorer versions 5.x or later and Opera.   And in WebKit-based browsers, there are pseudo-elements called the user who scrolls through the contents of a window by clicking one of the arrow buttons, clicking the area in the shaded scroll bar bay, or dragging the scroll area. When the user clicks an arrow button, the app scrolls through the content around a unit (usually a single row or column). When the user clicks the shaded areas, the app scrolls through the content around a window. The amount of scrolling that occurs when the user drags the scroll area depends on how far the user drags the scroll area and the scroll area of the scroll bar. For more information about the scroll area, see Scroll Area Position and Scroll Area. Horizontal scrolling, mouse terms, scrolling, software terms, vertical scrolling, scroll wheel mouse Although scroll bar designs differ throughout their history, they typically appear on one or both sides of the display area as long rectangular areas containing a bar (or thumb) that can be dragged along a hollow (or track) to move the body of the document. This can be placed vertically, horizontally, or both in the window, depending on the direction in which the content extends beyond its boundaries. Two arrows are often included at each end of the thumb or trough for more precise adjustments. The «thumb» has different names in different environments: on Mac OS X 10.4, it is called a «scroller»;  on the Java platform, it is called a «thumb» or «button»; The.
Microsoft`s NET documentation calls it a «scroll box» or «thumb scroll»; In other environments, it is called «elevator», «quint», «washer», «windshield wiper» or «handle»; In some environments where browsers use agnostic language for scroll bar terminology, the thumb is called «PEA» for vertical bar movement and always uses «puck» for horizontal movement. You can click the arrow keys on the keyboard to scroll up, down, left, or right on a page. This scrolling technique usually scrolls the screen very slowly compared to other scrolling techniques. When you click the arrow buttons, the page continues scrolling until one of the scrolling limits is reached. WebKit also provides many pseudo-classes to change the style of scroll bars.  Scroll bars are used with mouse, touchpad, or keyboard. You can use a mouse to move the scroll bar by clicking the scroll arrow at each end of the scroll bars. You can also click an empty part of the scroll bar or click and drag the scroll area. With a keyboard, you can use the up or down arrow keys to scroll a few lines at a time. Use the Page Up and Page Down keys or the spacebar to scroll down. Computer savvy users are often familiar with scroll bars, but those with limited knowledge may not understand them intuitively, especially when faced with new variations, without help.  Apart from literacy, several problems can be found in different types of scroll bars and their interactions.
In terms of design, if the size of the window is already small, the visible content area is further reduced by the presence of a scroll bar.  While some newer scroll bars help mitigate this problem, more traditional bars do not, especially when horizontal and vertical bars are present. To enable horizontal scrolling in a long text document, you can disable word wrapping. When working with images or other documents, zooming in also allows you to scroll horizontally. The horizontal scroll bar is often missing or disabled because displayed text or other content is wrapped or resized to prevent horizontal scrolling. For example, this web page does not scroll horizontally because it is set on the screen. If you are viewing a page that scrolls horizontally, you can scroll to the right by clicking the right scroll arrow in the horizontal scroll bar. You can set a page size for a scroll bar. The page size represents the number of data units that fit in the client area of the owner window at the current size.
For example, if the client pane can contain 16 lines of text, an application sets the page size to 16. The system uses the page size as well as the scroll area and length of the scroll bar tree to determine the size of the scroll area. When resizing a window with a scroll bar, an application must call the SetScrollInfo function to set the page size. An application can get the current page size by calling the Send GetScrollInfo function. In 1985, GEM used a proportionally large scrollbox, but worked identically to the Macintosh. The end result was a modern scroll bar that didn`t feel any different from the scroll bar in Windows today. GEM made it possible to move the mouse away from the scroll bar after clicking and holding to reduce coordination issues between the hand and the eye. AmigaOS followed later in the year, also with proportionally large scroll boxes. Some scroll bars include a visual location indicator that you can use to determine where the scroll action went or is moved in the content.  For multi-page content, scrolling may include an indicator of the current page number relative to the total number of pages next to the thumb, and wider scroll bars may provide an overview of the entire page.