Viewport · WebGlossary.info

In computer graphics, a polygon viewing region. ← Wikipedia
In web browsers, the region of the browser window which contains the visible portion of the document (web page). If the size of the viewport changes, for example as a result of the user resizing the browser window, the browser may reflow the document (i.e., recalculate the locations and sizes of elements of the document). If the document is larger than the viewport, the user can control the portion of the document which is visible by scrolling in the viewport. ← Wikipedia