PgUp key

The Page Up and Page Down keys (sometimes abbreviated as PgUp and PgDn) are two keys commonly found on computer keyboards.

The two keys are primarily used to scroll up or down in documents, but the scrolling distance varies between different applications. In word processors, for instance, they may jump by an emulated physical page or by a screen view that may show only part of one page or many pages at once depending on zoom factor. In cases when the document is shorter than one screenful, Page Up and Page Down often have no visible effect at all.

Operating systems differ as to whether the keys (pressed without modifier) just move the view – e.g. in Mac OS X – or also the input caret – e.g. in Microsoft Windows. In right-to-left settings, PgUp will move either upwards or rightwards (instead of left) and PgDn will move down or leftwards (instead of right). The keys have been dubbed previous page and next page, accordingly.

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Wikipedia