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A drop-down list (also drop down menu or drop-down menu or drop menu or pull-down list or simply a drop down) is a graphical control element, similar to a list box, that allows the user to choose one value from a list. When a drop-down list is inactive, it displays a single value. When activated, it displays (drops down) a list of values, from which the user may select one. When the user selects a new value, the control reverts to its inactive state, displaying the selected value. It is often used in the design of graphical user interfaces, including web design.
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Terminology
This type of control is called a "pop-up menu" on the Macintosh platform, however the term "popup menu" is used to refer to context menus in other GUI systems. The Macintosh also has the notion of "pull-down menus". The distinction is that, when the menu is closed, a pop-up menu's title shows the last-selected item while a pull-down menu shows a static title like a menu in the menu bar. Thus, the uses are different--popup menus are used to select a single option from a list while pull-down menus are used to issue commands or in cases where multiple options can be selected.
Source of the article : Wikipedia
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