What is the Pg up Key (Page up Key)
The Pg Up key is a computer key located between the keyboard and the numeric pad or on the numeric pad number 9. It can also be referred to as the Page Up key, the PGUP Key, the PU, or the PgUp key. On keyboards for PCs and Macs, the Page Up key is an industry-standard. Different programs have different interpretations of what it means, but it typically scrolls the document up one screenful. You may highlight the next Page in a text document by pressing and holding the Shift key while pressing the Page Up key.
The page view is shifted (scrolling) up one Page when this key is pushed if the Page being viewed has more than one Page. On every website page (including this one), press the Pg Dn key; for example, scroll the Page up one Page, but when you are at the top of the Page, using the Up button has no effect.
The Page Up key is typically used to scroll top in documents, but the amount of space that may be moved varies depending on the application. In word processors, for instance, they may skip over a real physical page or a screen view that, depending on the zoom factor, may only show a small portion of one Page or numerous pages at once. Page Up frequently doesn't have any effect when a document is too short to fit the entire screen.
The image below shows the Page Up key on a computer keyboard, including the numeric keypad and the primary keyboard.
Turn off the Num Lock so that pressing the number Nine on the keypad will act as a page-up key rather than the number 9.
Note: The Apple computer keyboard’s numerical keypad lacks a Page Up key. The Num Lock key and the option to make the 9 key a page-up key is absent from Apple computer keyboards.
Depending on the operating system, the keys (pushed without a modifier) may move the display only, as in Mac OS X, or they may also move the input caret as in Microsoft Windows. PgUp will change direction to the right or up in right-to-left configurations (instead of left).